Patent Publication Number: US-11387016-B2

Title: Transmission line substrate and electronic device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Japanese Patent Application No. 2016-098850 filed on May 17, 2016, Japanese Patent Application No. 2016-160664 filed on Aug. 18, 2016, Japanese Patent Application No. 2017-000843 filed on Jan. 6, 2017 and is a Continuation Application of PCT Application No. PCT/JP2017/018271 filed on May 16, 2017. The entire contents of each application are hereby incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a transmission line substrate, and more particularly to a transmission line substrate including a plurality of transmission lines and an electronic device including such a transmission line substrate. 
     2. Description of the Related Art 
     Conventionally, a transmission line substrate in which a stacked body obtained by stacking a plurality of insulating base materials includes a plurality of transmission lines has been known. 
     For example, International Publication No. 2013/103130 discloses a transmission line substrate provided with a first transmission line and a second transmission line that have a stripline structure and that are disposed in a stacking direction of a plurality of insulating base materials. In this transmission line substrate, a first ground conductor, a first signal line, an intermediate ground conductor, a second signal line, and a second ground conductor are respectively provided on different insulating base materials. The first transmission line is configured by the first ground conductor, the first signal line, and the intermediate ground conductor, and the second transmission line is configured by the intermediate ground conductor, the second signal line, and the second ground conductor. 
     However, in the structure of the transmission line substrate disclosed in International Publication No. 2013/103130, an insulating base material among the plurality of insulating base materials includes a large plane shaped ground conductor (in particular, the intermediate ground conductor provided between the first signal line and the second signal line in the stacking direction of the plurality of insulating base materials). In general, joining strength between an insulating base material and a conductor is weaker than joining strength between insulating base materials. Therefore, the joining strength between the insulating base material on which the ground conductor is provided and an insulating base material other than the insulating base material is reduced, so that the insulating base materials of a stacked body become easily separated from each other. As a result, the strength and durability of the transmission line substrate itself may be insufficient in some cases. 
     SUMMARY OF THE INVENTION 
     Preferred embodiments of the present invention provide transmission line substrates that achieve improved mechanical strength and durability against an external force and the like by significantly reducing or preventing separation of insulating base materials included in a stacked body from each other, in a structure in which the stacked body obtained by stacking a plurality of insulating base materials includes a plurality of transmission lines. 
     A transmission line substrate according to a preferred embodiment of the present invention includes a stacked body that includes a primary surface and includes a plurality of insulating base materials stacked on each other; a first signal line that is provided on any one of the plurality of insulating base materials; a second signal line that is provided on any one of the plurality of insulating base materials; a first ground conductor that is provided on any one of the plurality of insulating base materials; a second ground conductor that is provided on any one of the plurality of insulating base materials; a first interlayer connection conductor that is provided in any one of the plurality of insulating base materials; a plurality of first external connection electrodes that are provided on the primary surface and connected to the first signal line; a plurality of second external connection electrodes that are provided on the primary surface and connected to the second signal line; a first transmission line including the first signal line, the first ground conductor, and an insulating base material among the plurality of insulating base materials, the insulating base material being interposed between the first signal line and the first ground conductor; and a second transmission line including the second signal line, the second ground conductor, and an insulating base material among the plurality of insulating base materials, the insulating base material being interposed between the second signal line and the second ground conductor, and the stacked body has an elongated shape that extends in a transmission direction in which the first signal line and the second signal line extend; the second signal line is provided on a layer different from a layer on which the first signal line is provided and extends in parallel or substantially in parallel with the first signal line when viewed in a stacking direction in which the plurality of insulating base materials are stacked; the first ground conductor is provided on the same layer as the layer on which the second signal line is provided, and is overlapped with the first signal line when viewed in the stacking direction; the second ground conductor is provided on the same layer as the layer on which the first signal line is provided, and is overlapped with the second signal line when viewed in the stacking direction; the first interlayer connection conductor electrically connects the first ground conductor and the second ground conductor; the plurality of first external connection electrodes are respectively disposed in a vicinity of opposite ends of the stacked body in the transmission direction; and the plurality of second external connection electrodes are respectively disposed in a vicinity of opposite ends of the stacked body in the transmission direction. 
     In this configuration, the first transmission line and the second transmission line are disposed in the width direction of the stacked body, and a large ground conductor is not provided over the approximately whole area of the insulating base material. In other words, in comparison with a case in which a large ground conductor is provided over the approximately whole area of the insulating base material, the joining surface between the insulating base materials is relatively large. Therefore, according to this configuration, a decrease in the strength of partially or wholly joining of the insulating base materials is significantly reduced or prevented, and the insulating base materials of the stacked body is significantly reduced or prevented from being separated from each other, so that a transmission line substrate of which the mechanical strength and the durability against an external force and the like are improved is able to be obtained. 
     In addition, with this configuration, since the ground conductor that defines the transmission line substrate is provided on the same layer as the layer on which the signal line is provided, in comparison with a case in which the signal line and the ground conductor are provided on different layers, the number of insulating base materials required to provide a plurality of transmission lines is able to be reduced. Therefore, according to this configuration, in the configuration in which a plurality of transmission lines are provided in the stacked body obtained by stacking a plurality of insulating base materials, in comparison with a case in which the signal line and the ground conductor are provided on different layers, a thin transmission line substrate is able to be obtained. 
     In the above preferred embodiment of the present invention, the transmission line substrate may preferably include a third ground conductor that is provided on any one of the plurality of insulating base materials, a fourth ground conductor that is provided on any one of the plurality of insulating base materials, a second interlayer connection conductor that is provided in any one of the plurality of insulating base materials, and a third interlayer connection conductor that is provided in any one of the plurality of insulating base materials, and the third ground conductor may preferably be provided on a layer different from a layer on which the second ground conductor is provided, and may preferably be disposed so as to face the first ground conductor across the first signal line with respect to the stacking direction; the fourth ground conductor may preferably be provided on a layer different from a layer on which the first ground conductor is provided, and may preferably be disposed so as to face the second ground conductor across the second signal line with respect to the stacking direction; the second interlayer connection conductor may preferably electrically connect the second ground conductor and the third ground conductor; and the third interlayer connection conductor may preferably electrically connect the first ground conductor and the fourth ground conductor. 
     In this configuration, the ground conductor is disposed in the surrounding three directions of the first signal line, and the first signal line is surrounded by the ground conductor over the surrounding three directions of the first signal line. In addition, in this configuration, the ground conductor is disposed in the surrounding three directions of the second signal line, and the second signal line is surrounded by the ground conductor over the surrounding three directions of the second signal line. Therefore, according to this configuration, sufficient isolation between the first signal line and the second signal line is ensured, and the effect of reducing cross talk is enhanced. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a fifth ground conductor that is provided on any one of the plurality of insulating base materials, and a sixth ground conductor that is provided on any one of the plurality of insulating base materials, and the fifth ground conductor may preferably be provided on the same layer as a layer on which the first signal line and the second ground conductor are provided, may preferably extend in parallel or substantially in parallel with the first signal line, and may preferably be disposed opposite to the second ground conductor with respect to the first signal line; and the sixth ground conductor may preferably be provided on the same layer as a layer on which the second signal line and the first ground conductor are provided, may preferably extend in parallel or substantially in parallel with the second signal line, and may preferably be disposed opposite to the first ground conductor with respect to the second signal line. 
     In this configuration, the ground conductor is disposed in the surrounding four directions of the first signal line, and the first signal line is surrounded by the ground conductor over the surrounding four directions of the first signal line. In addition, in this configuration, the ground conductor is disposed in the surrounding four directions of the second signal line, and the second signal line is surrounded by the ground conductor over the surrounding four directions of the second signal line. Therefore, according to this configuration, sufficient isolation between the first signal line and the second signal line is ensured, and the effect of reducing cross talk is further enhanced. 
     In at least one of the above preferred embodiments of the present invention, each of the plurality of insulating base materials may preferably be made of a thermoplastic resin. 
     According to this configuration, a transmission line substrate of which the shape is able to be easily plastically processed according to a mounting state is able to be obtained. 
     In at least one of the above preferred embodiments of the present invention, the first transmission line and the second transmission line may preferably include a bent portion that is bent in the stacking direction. 
     In at least one of the above preferred embodiments of the present invention, the stacked body may preferably have flexibility. 
     With such a configuration, the features of various preferred embodiments of the present invention work more effectively. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably further include a ground conductor on the primary surface, the ground conductor being overlapped with all signal lines when viewed in the stacking direction. 
     With this configuration, unnecessary radiation from all the signal lines is significantly reduced or prevented more reliably. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a first intermediate ground conductor that is provided between the layer on which the first signal line is provided and the layer on which the second signal line is provided, with respect to the stacking direction, and the first intermediate ground conductor may preferably be disposed between the first signal line and the second signal line when viewed in the stacking direction. 
     According to this configuration, the isolation between the first signal line and the second signal line is further increased, and the effect of reducing cross talk is further enhanced. 
     In at least one of the above preferred embodiments of the present invention, the first intermediate ground conductor may preferably be spaced farther apart from the first signal line or the second signal line than at least one of other ground conductors. 
     According to this configuration, the isolation between the first signal line and the second signal line is able to be increased without greatly affecting capacitance to be generated between the first signal line and the other ground conductors. 
     In at least one of the above preferred embodiments of the present invention, the first intermediate ground conductor, when viewed in the stacking direction, may preferably include a portion that, when viewed in the stacking direction, extends farther toward the first signal line than to the second ground conductor and is not overlapped with the second ground conductor. 
     According to this configuration, since the first intermediate ground conductor is disposed closer to the first signal line, the magnetic field to be generated around the first signal line is effectively shielded, and the isolation between the first signal line and the second signal line is able to be further increased. 
     In at least one of the above preferred embodiments of the present invention, the first intermediate ground conductor, when viewed in the stacking direction, may preferably include a portion that, when viewed in the stacking direction, extends farther toward the second signal line than to the first ground conductor and is not overlapped with the first ground conductor. 
     According to this configuration, since the first intermediate ground conductor is disposed closer to the second signal line, the magnetic field to be generated around the second signal line is effectively shielded, and the isolation between the first signal line and the second signal line is able to be further increased. 
     In at least one of the above preferred embodiments of the present invention, the first intermediate ground conductor may preferably have a thickness smaller in the stacking direction than a thickness of the other ground conductors. 
     Since the first intermediate ground conductor is disposed at position that is overlapped with a large number of conductors in the stacking direction, irregularities are easily formed on the surface of the transmission line substrate after the stacked body is obtained. However, according to this configuration, irregularities are able to be significantly reduced or prevented from being formed on the surface of the transmission line substrate. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a third signal line that extends in parallel or substantially in parallel with the second signal line, and the third signal line may preferably be disposed at the same position as the second signal line in the stacking direction; the third signal line may preferably be disposed opposite to the second signal line across the first ground conductor in a width direction that is perpendicular or substantially perpendicular to the stacking direction and a parallel direction in which signal lines extend in parallel or substantially in parallel with each other; and the third signal line may preferably be disposed at a position symmetric to the second signal line with respect to a reference plane that extends through a center in a width direction of the first ground conductor and is in parallel or substantially in parallel to the parallel direction and the stacking direction. 
     With this configuration, since the second signal line and the third signal line are symmetrically disposed in the width direction of the stacked body, the physical and electromagnetic balance in the width direction in the stacked body is improved. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a third transmission line that includes the third signal line, and the third transmission line and the second transmission line may preferably be disposed at positions symmetric to each other with respect to the reference plane. 
     With this configuration, since the second transmission line and the third transmission line are symmetrically disposed in the width direction of the stacked body, the physical and electromagnetic balance in the width direction in the stacked body is improved. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a fourth signal line that extends in parallel or substantially in parallel with the first signal line, and the fourth signal line may preferably be disposed at a position symmetric to the first signal line with reference to the first ground conductor in the stacking direction. 
     With this configuration, since the first signal line and the fourth signal line are symmetrically disposed in the stacking direction of the stacked body, the structural balance in the stacking direction in the stacked body is improved and the electromagnetic balance is also improved. Therefore, the occurrence of uneven irregularities of the transmission line substrate is significantly reduced or prevented, and the mounting performance of the transmission line substrate to be mounted on a circuit board or the like is improved. In addition, a warp in the stacking direction of the transmission line substrate is significantly reduced or prevented from occurring. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include a fourth transmission line that includes the fourth signal line, and the fourth transmission line and the first transmission line may preferably be disposed at positions symmetric to each other with reference to the first ground conductor. 
     With this configuration, since the first transmission line and the fourth transmission line are symmetrically disposed in the stacking direction of the stacked body, the physical and electromagnetic balance in the stacking direction in the stacked body is improved. 
     In at least one of the above preferred embodiments of the present invention, the transmission line substrate may preferably include transmission lines of a predetermined number, and the transmission lines of a predetermined number may preferably include five or more transmission lines that include the first transmission line to the fourth transmission line, and the transmission lines of a predetermined number may preferably be symmetrically disposed in the stacking direction and a first direction perpendicular or substantially perpendicular to the stacking direction. 
     With this configuration, since all the transmission lines in the stacked body are symmetrically disposed, the physical and electromagnetic balance is further improved. 
     An electronic device includes a transmission line substrate according to any one of the above described preferred embodiments of the present invention, and a circuit board on which the transmission line substrate is surface-mounted. 
     With this configuration, an electronic device of which the reliability is improved and in which the electromagnetic coupling between the transmission line substrate and the circuit board is significantly reduced or prevented is achieved. 
     In the electronic device according to the above-described preferred embodiment, the circuit board may preferably include a mounting surface; the first signal line may preferably be disposed closer to the mounting surface than the second signal line is; the transmission line substrate may preferably include a second intermediate ground conductor that is provided between the mounting surface and the layer on which the first signal line is provided, with respect to the stacking direction; and the second intermediate ground conductor may preferably be disposed between the first signal line and the second signal line when viewed in the stacking direction. 
     According to this configuration, a magnetic field that is generated around the first signal line significantly reduces or prevents the first signal line and a conductor that is provided in contact with the circuit board from being coupled to each other. 
     In an electronic device according to at least one of the above-described preferred embodiments of the present invention, the second intermediate ground conductor may preferably be spaced farther apart from the first signal line than at least one of the other ground conductors. 
     According to this configuration, the coupling between the first signal line and the conductor that is provided in contact with the circuit board is able to be significantly reduced or prevented without greatly affecting capacitance to be generated between the first signal line and the other ground conductors. 
     In an electronic device according to at least one of the above-described preferred embodiments of the present invention, the second intermediate ground conductor may preferably include a portion that, when viewed in the stacking direction, extends farther toward the first signal line than to the second ground conductor and is not overlapped with the second ground conductor. 
     With this configuration, since the second intermediate ground conductor is disposed closer to the first signal line, the magnetic field to be generated around the first signal line is effectively shielded, and the coupling between the first signal line and the conductors provided in contact with the circuit board is able to be significantly reduced or prevented. 
     In an electronic device according to at least one of the above-described preferred embodiments of the present invention, the second intermediate ground conductor may preferably have a thickness smaller in the stacking direction than a thickness of the other ground conductors. 
     Since the second intermediate ground conductor is disposed at position that is overlapped with a large number of conductors in the stacking direction, irregularities are easily formed on the surface of the transmission line substrate after the stacked body is obtained. However, according to this configuration, irregularities are able to be significantly reduced or prevented from being formed on the surface of the multilayer substrate. 
     According to various preferred embodiments of the present invention, in a configuration in which a stacked body obtained by stacking a plurality of insulating base materials includes a plurality of transmission lines, it is possible to provide a transmission line substrate of which the mechanical strength and the durability against an external force and the like are improved by significantly reducing or preventing separation of the insulating base materials of the stacked body from each other. 
     The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of a multilayer substrate  101  according to a first preferred embodiment of the present invention, and  FIG. 1B  is an exploded perspective view of the multilayer substrate  101 . 
         FIG. 2  is an A-A cross-sectional view of the multilayer substrate  101  in  FIG. 1A . 
         FIG. 3  is a cross-sectional view of a main portion of an electronic device  201  according to the first preferred embodiment of the present invention. 
         FIG. 4  includes cross-sectional diagrams sequentially showing steps for manufacturing a multilayer substrate  101 A. 
         FIG. 5A  is a perspective view of a multilayer substrate  102  according to a second preferred embodiment of the present invention and  FIG. 5B  is an exploded perspective view of the multilayer substrate  102 . 
         FIG. 6  is a B-B cross-sectional view of the multilayer substrate  102  in  FIG. 5A . 
         FIG. 7A  is a perspective view of a multilayer substrate  103  according to a third preferred embodiment of the present invention and  FIG. 7B  is an exploded perspective view of a line portion SL of the multilayer substrate  103 . 
         FIG. 8  is a C-C cross-sectional view of the multilayer substrate  103  in  FIG. 7A . 
         FIG. 9  is a perspective view of a multilayer substrate  104  according to a fourth preferred embodiment of the present invention. 
         FIG. 10  is a cross-sectional view of a line portion of a multilayer substrate  105  according to a fifth preferred embodiment of the present invention. 
         FIGS. 11A to 11D  are exploded plan views of a multilayer substrate  106  according to a sixth preferred embodiment of the present invention. 
         FIG. 12  is a cross-sectional view of the multilayer substrate  106  according to the sixth preferred embodiment of the present invention. 
         FIGS. 13A to 13D  are exploded plan views of a multilayer substrate  107  according to a seventh preferred embodiment of the present invention. 
         FIGS. 14A to 14D  are exploded plan views of a multilayer substrate  108  according to an eighth preferred embodiment of the present invention. 
         FIG. 15  is a cross-sectional view of a multilayer substrate  109  according to a ninth preferred embodiment of the present invention. 
         FIG. 16  is a cross-sectional view of a multilayer substrate  110  according to a tenth preferred embodiment of the present invention. 
         FIG. 17  is an external perspective view of an electronic device  202  according to the tenth preferred embodiment of the present invention. 
         FIG. 18A  is a cross-sectional view of a multilayer substrate  111  according to an eleventh preferred embodiment of the present invention, and  FIG. 18B  is an enlarged cross-sectional view of a ZP portion in  FIG. 18A . 
         FIG. 19  is an external perspective view of an electronic device  203  according to the eleventh preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, a plurality of preferred embodiments of the present invention will be described with reference to the attached drawings and several specific examples. In the drawings, the same components and elements are denoted by the same reference signs. While preferred embodiments are divided and described for the sake of convenience in consideration of ease of description or understanding of main points, elements described in different preferred embodiments are able to be partially replaced and combined with each other. In preferred embodiments after the second preferred embodiment, a description of features common to the first preferred embodiment will be omitted, and different features are primarily described. In particular, a description of similar operational effects achieved by similar structures will not be repeated in each preferred embodiment. 
     First Preferred Embodiment 
       FIG. 1A  is a perspective view of a multilayer substrate  101  according to a first preferred embodiment of the present invention, and  FIG. 1B  is an exploded perspective view of the multilayer substrate  101 .  FIG. 2  is an A-A cross-sectional view of the multilayer substrate  101  in  FIG. 1A . The multilayer substrate is a non-limiting example of a “transmission line substrate” according to various preferred embodiments of the present invention. 
     The multilayer substrate  101  includes a stacked body  10  obtained by stacking a plurality of insulating base materials  11 ,  12 ,  13 , and  14 , a conductor (such as a first signal line  41 , a second signal line  42 , a first ground conductor  31 , a second ground conductor  32 , a third ground conductor  33 , a fourth ground conductor  34 , a first interlayer connection conductor V 1 , a second interlayer connection conductor V 2 , and a third interlayer connection conductor V 3 ) provided in any one of the plurality of insulating base materials  11 ,  12 ,  13 , and  14 , and a protective layer  1 . As illustrated in  FIG. 1A , the multilayer substrate  101  includes a line portion SL, a first connection portion CP 1 , and a second connection portion CP 2 . 
     The stacked body  10  has a rectangular or substantially rectangular parallelepiped shape having a longitudinal direction that coincides with the X-axis direction, and includes a first principal surface VS 1  and a second primary surface VS 2  that face each other. As illustrated in  FIG. 1B , the stacked body  10  is obtained by stacking the insulating base materials  11 ,  12 ,  13 , and  14  in this order. The protective layer  1  is provided on the first primary surface VS 1  of the stacked body  10 . 
     The plurality of insulating base materials  11 ,  12 ,  13 , and  14  are each provided as a plate that includes a rectangular or substantially rectangular shape and a longitudinal direction that coincides with the X-axis direction. The plurality of insulating base materials  11 ,  12 ,  13 , and  14  are plates made of a thermoplastic resin, for example, and are sheets made of a liquid crystal polymer as a primary material and having flexibility. 
     A third ground conductor  33  is provided on the surface of the insulating base material  11 . The third ground conductor  33  is a rectangular or substantially rectangular conductor that is disposed closer to a first side (the lower side of the insulating base material  11  in  FIG. 1B ) than to the center of the insulating base material  11  and includes a longitudinal direction that coincides with the X-axis direction. The third ground conductor  33  is a conductor pattern made of a material such as a Cu foil, for example. 
     A first signal line  41  and a second ground conductor  32  are provided on the surface of the insulating base material  12 . The first signal line  41  is a conductor that is disposed between a first side (the lower side of the insulating base material  12  in  FIG. 1B ) and the center of the insulating base material  12  and extends in the X-axis direction. The second ground conductor  32  is a rectangular or substantially rectangular conductor that is disposed closer to a second side (the upper side of the insulating base material  12 ) than to the center of the insulating base material  12  and includes a longitudinal direction that coincides with the X-axis direction. The first signal line  41  and the second ground conductor  32  are each a conductor pattern made of a material such as a Cu foil, for example. 
     In addition, the insulating base material  12  includes six second interlayer connection conductors V 2 , for example. The six second interlayer connection conductors V 2  are conductors that are disposed in the center in the Y-axis direction of the insulating base material  12  and are arranged in the X-axis direction. As illustrated in  FIG. 1B , the second interlayer connection conductors V 2  electrically connect the second ground conductor  32  and the third ground conductor  33  to each other. The second interlayer connection conductors V 2  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     A second signal line  42 , a first ground conductor  31 , and first signal conductors  51  and  52  are provided on the surface of the insulating base material  13 . The second signal line  42  is a conductor that is disposed closer to a second side (the upper side of the insulating base material  13  in  FIG. 1B ) than to the center of the insulating base material  13  and extends in the X-axis direction. The first ground conductor  31  is a conductor that is disposed between a first side (the lower side of the insulating base material  13 ) and the center of the insulating base material  13 . The first signal conductor  51  is a rectangular or substantially rectangular shaped conductor disposed in the vicinity of a first end (the left end of the insulating base material  13  in  FIG. 1B ) of the insulating base material  13 , and the first signal conductor  52  is a rectangular or substantially rectangular shaped conductor disposed in the vicinity of a second end (the right end of the insulating base material  13 ) of the insulating base material  13 . The second signal line  42 , the first ground conductor  31 , and the first signal conductors  51  and  52  are each a conductor pattern made of a material such as a Cu foil, for example. 
     In addition, the insulating base material  13  includes eight first interlayer connection conductors V 1  and interlayer connection conductors V 11  and V 12 , for example. The eight first interlayer connection conductors V 1  are conductors that are disposed in the center in the Y-axis direction of the insulating base material  13  and are arranged in the X-axis direction. The first interlayer connection conductors V 1  electrically connect the first ground conductor  31  and the second ground conductor  32  to each other. The interlayer connection conductor V 11  electrically connects the first signal conductor  51  and a first end (the left end of the first signal line  41  in  FIG. 1B ) of the first signal line  41  to each other. The interlayer connection conductor V 12  electrically connects the first signal conductor  52  and a second end (the right end of the first signal line  41 ) of the first signal line  41  to each other. The first interlayer connection conductors V 1  and the interlayer connection conductors V 11  and V 12  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     A fourth ground conductor  34 , first signal conductors  61  and  62 , and second signal conductors  71  and  72  are provided on the surface of the insulating base material  14 . The fourth ground conductor  34  is a conductor that is disposed between a second side (the upper side of the insulating base material  14  in  FIG. 1B ) and the center of the insulating base material  14 . The first signal conductor  61  and the second signal conductor  71  are rectangular or substantially rectangular shaped conductors disposed in the vicinity of a first end (the left end of the insulating base material  14 ) of the insulating base material  14 . The first signal conductor  62  and the second signal conductor  72  are rectangular or substantially rectangular shaped conductors disposed in the vicinity of a second end (the right end of the insulating base material  14 ) of the insulating base material  14 . The fourth ground conductor  34 , the first signal conductors  61  and  62 , and the second signal conductors  71  and  72  are each a conductor pattern made of a material such as a Cu foil, for example. 
     In addition, the insulating base material  14  includes 10 third interlayer connection conductors V 3  and interlayer connection conductors V 13 , V 14 , V 21 , and V 22 . The 10 third interlayer connection conductors V 3  are conductors that are disposed in the center in the Y-axis direction of the insulating base material  14  and are arranged in the X-axis direction. The third interlayer connection conductors V 3  electrically connect the first ground conductor  31  and the fourth ground conductor  34  to each other. The interlayer connection conductor V 13  electrically connects the first signal conductor  61  and the first signal conductor  51  to each other, and the interlayer connection conductor V 14  electrically connects the first signal conductor  62  and the first signal conductor  52  to each other. The interlayer connection conductor V 21  electrically connects the second signal conductor  71  and a first end (the left end of the second signal line  42  in  FIG. 1B ) of the second signal line  42  to each other. The interlayer connection conductor V 22  electrically connects the second signal conductor  72  and a second end (the right end of the second signal line  42 ) of the second signal line  42  to each other. The third interlayer connection conductors V 3  and the interlayer connection conductors V 13 , V 14 , V 21 , and V 22  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     The protective layer  1  includes the same or substantially the same shape in a plan view as the insulating base material  14 , and is provided on the upper surface of the insulating base material  14 . The protective layer  1  includes opening portions AP 2  and AP 6  at positions corresponding to the positions of the first signal conductors  61  and  62 , and includes opening portions AP 1  and AP 5  at positions corresponding to the positions of the second signal conductors  71  and  72 . In addition, the protective layer  1  includes opening portions AP 3  and AP 4  at positions in the vicinity of the opening portions AP 1  and AP 2  and corresponding to the position of the fourth ground conductor  34 . Further, the protective layer  1  includes opening portions AP 7  and AP 8  at positions in the vicinity of the opening portions AP 5  and AP 6  and corresponding to the position of the fourth ground conductor  34 . The protective layer  1  is a solder resist film, for example. 
     Therefore, even when the protective layer  1  is provided on the first primary surface VS 1  of the stacked body  10  (that is, the protective layer  1  is stacked on the upper surface of the insulating base material  14 ), the first signal conductors  61  and  62 , the second signal conductors  71  and  72 , and a portion of the fourth ground conductor  34  (ground conductors  81 ,  82 ,  83 , and  84  in  FIG. 1A ) are exposed on the first primary surface VS 1  of the stacked body  10 . In the first preferred embodiment, each of the first signal conductors  61  and  62  corresponds to a “first external connection electrode”, and each of the second signal conductors  71  and  72  corresponds to a “second external connection electrode”. 
     In the first preferred embodiment, the first connection portion CP 1  is provided in the vicinity of the first end (the left end of the stacked body  10  in  FIG. 1A ) of the rectangular or substantially rectangular parallelepiped-shaped stacked body  10  in which the first signal conductor  61 , the second signal conductor  71 , and the ground conductors  81  and  82  are provided. In addition, in the first preferred embodiment, the second connection portion CP 2  is provided in the vicinity of the second end (the right end of the stacked body  10 ) of the stacked body  10  in which the first signal conductor  62 , the second signal conductor  72 , and the ground conductors  83  and  84  are provided. In other words, the multilayer substrate  101  includes the first connection portion CP 1 , the line portion SL, and the second connection portion CP 2  that are disposed in this order in the X-axis direction. 
     As illustrated in  FIG. 1B ,  FIG. 2 , and other drawings, the second signal line  42  is provided on a layer different from the layer on which the first signal line  41  is provided, and extends in parallel or substantially in parallel with the first signal line  41  when viewed in the stacking direction (the Z-axis direction) of the plurality of insulating base materials  11 ,  12 ,  13 , and  14 . 
     In addition, as illustrated in  FIG. 2  and other drawings, the first ground conductor  31  is provided on the same layer as the layer on which the second signal line  42  is provided, and is overlapped with the first signal line  41  when viewed in the Z-axis direction. The second ground conductor  32  is provided on the same layer as the layer on which the first signal line  41  is provided, and is overlapped with the second signal line  42  when viewed in the Z-axis direction. 
     Further, as illustrated in  FIG. 2  and other drawings, the third ground conductor  33  is provided on a layer different from the layer on which the second ground conductor  32  is provided, and is disposed to face the first ground conductor  31  across the first signal line  41  with respect to the Z-axis direction. The fourth ground conductor  34  is provided on a layer different from the layer on which the first ground conductor  31  is provided, and is disposed to face the second ground conductor  32  across the second signal line  42  with respect to the Z-axis direction. 
     In the first preferred embodiment, as illustrated in  FIG. 2 , the first signal line  41 , the first ground conductor  31 , the third ground conductor  33 , the insulating base material  13  interposed between the first signal line  41  and the first ground conductor  31 , and the insulating base material  12  interposed between the first signal line  41  and the third ground conductor  33  define a first transmission line CL 1 . In addition, in the first preferred embodiment, the second signal line  42 , the second ground conductor  32 , the fourth ground conductor  34 , the insulating base material  13  interposed between the second signal line  42  and the second ground conductor  32 , and the insulating base material  14  interposed between the second signal line  42  and the fourth ground conductor  34  define a second transmission line CL 2 . 
     According to the multilayer substrate  101  according to the first preferred embodiment of the present invention, the following advantageous effects may be obtained. 
     In the multilayer substrate  101 , the first transmission line CL 1  and the second transmission line CL 2  are disposed in the width direction (the Y-axis direction) of the stacked body  10 , and a large ground conductor is not provided over the approximately whole area of the insulating base material. In other words, in comparison with a case in which a large ground conductor is provided over the approximately whole area of the insulating base material, the joining surface between the insulating base materials is relatively large. Therefore, with this configuration, a decrease in the strength of partially or wholly joining of the insulating base materials is significantly reduced or prevented, and, since the insulating base materials of the stacked body  10  are significantly reduced or prevented from being separated from each other, a multilayer substrate of which the mechanical strength and the durability against an external force and the like are improved is able to be obtained. In particular, in a case in which a stacked body having flexibility is used, interlayer separation during deformation is significantly reduced or prevented, and the configuration of the first preferred embodiment of the present invention provides greater advantageous effects. 
     In addition, in the first preferred embodiment, the first transmission line CL 1  and the second transmission line CL 2  are disposed in the Y-axis direction, and the ground conductor (the first ground conductor  31  or the second ground conductor  32 ) defining a transmission line is provided on the same layer as the layer on which the signal line (the first signal line  41  or the second signal line  42 ) is provided. Therefore, in comparison with a configuration (in a case in which the signal line and the ground conductor are provided on different layers) in which a plurality of transmission lines are disposed in the Z-axis direction, the number of insulating base materials required to provide a plurality of transmission lines is able to be reduced. Therefore, with this configuration, in the configuration in which a plurality of transmission lines are provided in the stacked body obtained by stacking a plurality of insulating base materials, in comparison with a case in which the signal line and the ground conductor are provided on different layers, a thin multilayer substrate is able to be obtained. 
     In addition, since the ground conductor (the first ground conductor  31  or the second ground conductor  32 ) is provided on the same layer as the layer on which the signal line (the first signal line  41  or the second signal line  42 ) is provided, in comparison with a case in which the ground conductor is provided on a layer different from the layer on which the signal line is provided, isolation between first signal line  41  and second signal line  42  is able to be increased. 
     In the first preferred embodiment, as illustrated in  FIG. 2  and other drawings, since the first interlayer connection conductor V 1  is disposed between the signal lines (between the first signal line  41  and the second signal lines  42 ), the isolation between the signal lines is able to be increased. It is to be noted that, similarly to the multilayer substrate  101  according to the first preferred embodiment, a plurality of first interlayer connection conductors V 1  provided between the signal lines are able to further increase the isolation. Further, in the first preferred embodiment, since the distance between the first ground conductor  31  and the second ground conductor  32  is small in the stacking direction, the occurrence of conductive failure of the first interlayer connection conductor V 1  is significantly reduced or prevented. 
     In the first preferred embodiment, the ground conductors (the first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 , the first interlayer connection conductor V 1 , and the second interlayer connection conductor V 2 ) are disposed in the surrounding three directions (the positive Y direction, the positive Z direction, and the negative Z direction with respect to the first signal line  41  in  FIG. 2 ) of the first signal line  41 , and the first signal line  41  is surrounded by the ground conductors in the surrounding three directions. In addition, in the first preferred embodiment, the ground conductors (the first ground conductor  31 , the second ground conductor  32 , the fourth ground conductor  34 , the first interlayer connection conductor V 1 , and the third interlayer connection conductor V 3 ) are disposed in the surrounding three directions (the negative Y direction, the positive Z direction, and the negative Z direction with respect to the second signal line  42  in  FIG. 2 ) of the second signal line  42 , and the second signal line  42  is surrounded by the ground conductors in the surrounding three directions. Therefore, with this configuration, sufficient isolation between the first signal line  41  and the second signal line  42  is ensured, and the effect of reducing cross talk is enhanced. 
     In the first preferred embodiment, the plurality of insulating base materials  11 ,  12 ,  13 , and  14  that define the stacked body  10  are each made of thermoplastic resin in the present preferred embodiment, respectively. With this configuration, as described in detail below, a multilayer substrate of which the shape is able to be plastically processed easily according to a mounted state (such as irregularities of a mounting destination) is able to be obtained. 
     Subsequently, an example of mounting a multilayer substrate according to a preferred embodiment of the present invention will be described with reference to the drawings.  FIG. 3  is a cross-sectional view of a main portion of an electronic device  201  according to the first preferred embodiment of the present invention. 
     The electronic device  201  according to the first preferred embodiment includes a multilayer substrate  101 A and a circuit board  301 . The multilayer substrate  101 A is different from the multilayer substrate  101  in that the first transmission line and the second transmission line of the multilayer substrate  101 A include a bent portion (to be described in detail later) bent in the Z-axis direction. Other configurations are substantially the same as the configurations of the multilayer substrate  101 . The circuit board  301  includes a first surface PS 1  and a second surface PS 2 . Both the first surface PS 1  and the second surface PS 2  are surfaces in parallel or substantially parallel to the XY plane, and are surfaces located at different heights in the Z-axis direction. 
     As illustrated in  FIG. 3 , the multilayer substrate  101 A is mounted on the circuit board  301 . The first surface PS 1  of the circuit board  301  includes conductors  91  and  92  and the like and the second surface PS 2  of the circuit board  301  includes conductors  93  and  94  and the like. The ground conductor  81 , the second signal conductor  71 , and the like of the multilayer substrate  101 A are respectively connected to the conductors  91  and  92  and the like provided on the first surface PS 1  through a conductive joining material  4  such as solder. The second signal conductor  72  and the ground conductor  84  and the like of the multilayer substrate  101 A are respectively connected to the conductors  93  and  94  and the like provided on the second surface PS 2  through a conductive joining material  4  such as solder. Although not shown, the first signal conductor is also connected to the conductor provided on the surface of the circuit board  301 . 
     As described above, the multilayer substrate  101 A (the first transmission line and the second transmission line), since including the bent portion bent in the Z-axis direction, is easily mounted on the circuit board  301  including surfaces located at different heights in the Z-axis direction. 
     The multilayer substrate  101 A according to the first preferred embodiment is manufactured by, for example, the following steps.  FIG. 4  includes cross-sectional diagrams sequentially showing steps for manufacturing the multilayer substrate  101 A. 
     (1) First, an insulating base material layer (thermoplastic resin) in a collective substrate state and a protective layer, the insulating base material layer being obtained by patterning a signal line, a ground conductor, and the like, are stacked to define a stacked body in a collective substrate state, then the stacked body in the collective substrate state is divided to an individual element, and a multilayer substrate  101  illustrated in step (1) in  FIG. 4  is obtained. 
     (2) Subsequently, as illustrated in step (2) in  FIG. 4 , the first primary surface VS 1  and the second primary surface VS 2  of the stacked body  10  are heated and pressurized in the Z-axis direction (see the arrows in  FIG. 4 ), by using an upper mold  5  and a lower mold  6 . It is to be noted that the positions to be heated and pressurized are in the vicinity of the center in the longitudinal direction (the X-axis direction) of the stacked body  10 , as illustrated in  FIG. 4 . The upper mold  5  and the lower mold  6  includes a structure with an L-shaped or substantially L-shaped cross section. 
     After the thermoplastic resin of the stacked body  10  is cooled and solidified, the stacked body  10  is removed from the upper mold  5  and the lower mold  6 , and a multilayer substrate  101 A is obtained. With such a manufacturing method, it is possible to obtain a multilayer substrate  101 A of which the bent shape is maintained (retained). 
     As described above, the shape of the multilayer substrate  101  according to the first preferred embodiment of the present invention is able to be plastically processed easily according to a mounted state (such as irregularities of a mounting destination) since the insulating base materials of the stacked body  10  are made of thermoplastic resin. 
     It is to be noted that, while the first preferred embodiment of the present invention provides an example of a multilayer substrate including a bent portion bent in the Z-axis direction in the vicinity of the center in the longitudinal direction (the X-axis direction) of the stacked body  10 , the present invention is not limited to such a configuration. The multilayer substrate may include a structure with a bent portion bent in the X-axis direction or the Y-axis direction. In addition, the multilayer substrate may include a structure with a bent portion at a position (a position between the first connection portion CP 1  and the center in the longitudinal direction of the stacked body  10 , for example) other than the center in the longitudinal direction (the X-axis direction) of the stacked body  10 . 
     In addition, while the first preferred embodiment of the present provides an example in which a conductor (the first signal conductors  61  and  62 , the second signal conductors  71  and  72 , and the ground conductors  81 ,  82 ,  83 , and  84 ) is provided on the first connection portion CP 1  and the second connection portion CP 2  of the multilayer substrate  101 , the present invention is not limited to this example. A connector may be mounted on the first connection portion CP 1  and the second connection portion CP 2  of the multilayer substrate. 
     Second Preferred Embodiment 
     A second preferred embodiment of the present invention describes a multilayer substrate including a stacked body  10 A obtained by stacking two insulating base materials and a protective layer. 
       FIG. 5A  is a perspective view of a multilayer substrate  102  according to the second preferred embodiment of the present invention and  FIG. 5B  is an exploded perspective view of the multilayer substrate  102 .  FIG. 6  is a B-B cross-sectional view of the multilayer substrate  102  in  FIG. 5A . 
     The multilayer substrate  102  includes a stacked body  10 A obtained by stacking a plurality of insulating base materials  12  and  13 , a conductor provided on any one of the plurality of insulating base materials  12  and  13 , and a protective layer  1 . The stacked body  10 A, as illustrated in  FIG. 5B , is obtained by stacking the two insulating base materials  12  and  13  in this order. The stacked body  10 A further includes the protective layer  1  provided on the first primary surface VS 1  of the stacked body  10 A. 
     A first signal line  41  and a second ground conductor  32  are provided on the surface of the insulating base material  12 . The configurations of the first signal line  41  and the second ground conductor  32  are the same or substantially the same as the configurations according to the first preferred embodiment. It is to be noted that a second interlayer connection conductor (the second interlayer connection conductor V 2  in  FIG. 1B ) is not provided in the insulating base material  12  according to the second preferred embodiment. 
     A second signal line  42 , a first ground conductor  31 , and first signal conductors  51  and  52  are provided on the surface of the insulating base material  13 . In addition, the insulating base material  13  includes eight first interlayer connection conductors V 1  and interlayer connection conductors V 11  and V 12 , for example. The configurations of the second signal line  42 , the first ground conductor  31 , the first signal conductors  51  and  52 , the first interlayer connection conductor V 1 , and the interlayer connection conductors V 11  and V 12  are the same or substantially the same as the configurations according to the first preferred embodiment. 
     The protective layer  1  includes the same or substantially the same shape in a plan view as the insulating base material  13 , and is provided on the upper surface of the insulating base material  13 . The protective layer  1  includes opening portions AP 2  and AP 6  at positions corresponding to the positions of the first signal conductors  51  and  52 , and includes opening portions AP 1  and AP 5  at positions corresponding to the positions of the first end and second end of the second signal line  42 . In addition, the protective layer  1  includes opening portions AP 3  and AP 4  at positions in the vicinity of the opening portions AP 1  and AP 2  and corresponding to the position of the first ground conductor  31 . Further, the protective layer  1  includes opening portions AP 7  and AP 8  at positions in the vicinity of the opening portions AP 5  and AP 6  and corresponding to the position of the first ground conductor  31 . 
     Therefore, even when the protective layer  1  is provided on the upper surface of the insulating base material  13 , the first signal conductors  51  and  52 , a portion of the second signal line (the second signal conductors  73  and  74  in  FIG. 5A ), and a portion of the first ground conductor  31  (ground conductors  85 ,  86 ,  87 , and  88 ) are exposed on the first primary surface VS 1  of the stacked body  10 A. In the second preferred embodiment, each of the first signal conductors  51  and  52  corresponds to a “first external connection electrode”, and each of the second signal conductors  73  and  74  in  FIG. 5A  corresponds to a “second external connection electrode”. 
     In the second preferred embodiment, as illustrated in  FIG. 6 , the first signal line  41 , the first ground conductor  31 , and the insulating base material  13  interposed between the first signal line  41  and the first ground conductor  31  defines a first transmission line CL 1 . In addition, in the second preferred embodiment, the second signal line  42 , the second ground conductor  32 , and the insulating base material  13  interposed between the second signal line  42  and the second ground conductor  32  defines a second transmission line CL 2 . 
     Since the number of insulating base materials defining a stacked body according to the second preferred embodiment is smaller than the number of insulating base materials of the stacked body  10  according to the first preferred embodiment, a multilayer substrate that is thinner than the multilayer substrate  101  according to the first preferred embodiment is able to be obtained. However, in terms of ensuring the isolation between the first transmission line CL 1  and the second transmission line CL 2 , the configuration according to the first preferred embodiment is preferable. 
     It is to be noted that, while the first preferred embodiment of the present provides an example in which the first signal line  41  and the second ground conductor  32  are provided on the front surface of the insulating base material  12  and the second signal line  42  and the first ground conductor  31  provided on the front surface of the insulating base material  13 , the present invention is not limited to such a configuration. For example, the second signal line  42  and the first ground conductor  31  may be provided on the front surface of the insulating base material  13 , and the first signal line  41  and the second ground conductor  32  may be provided on the rear surface of the insulating base material  13 . 
     Third Preferred Embodiment 
     A third preferred embodiment of the present invention describes a multilayer substrate further including a fifth ground conductor and a sixth ground conductor. 
       FIG. 7A  is a perspective view of a multilayer substrate  103  according to the third preferred embodiment of the present invention and  FIG. 7B  is an exploded perspective view of a line portion SL of the multilayer substrate  103 .  FIG. 8  is a C-C cross-sectional view of the multilayer substrate  103  in  FIG. 7A . 
     The multilayer substrate  103  is different from the multilayer substrate  101  according to the first preferred embodiment in that the multilayer substrate  103  further includes a conductor (a fifth ground conductor  35 , a sixth ground conductor  36 , a fourth interlayer connection conductor V 4 , a fifth interlayer connection conductor V 5 , a sixth interlayer connection conductor V 6 , and a seventh interlayer connection conductor V 7 ) provided in any one of the plurality of insulating base materials  11 ,  12 ,  13 , and  14 . Other configurations are substantially the same as the configurations of the multilayer substrate  101 . 
     As illustrated in  FIG. 7B , a first signal line  41 , a second ground conductor  32 , and a fifth ground conductor  35  are provided on the surface of the insulating base material  12 . The fifth ground conductor  35  is a conductor that is disposed in the vicinity of the first side (the lower side of the insulating base material  12  in  FIG. 7B ) of the insulating base material  12  and extends in the X-axis direction. The fifth ground conductor  35  is a conductor pattern made of a material such as a Cu foil, for example. 
     In addition, the insulating base material  12  includes a plurality of second interlayer connection conductors V 2 , and a plurality of sixth interlayer connection conductors V 6 . The plurality of sixth interlayer connection conductors V 6  are conductors that are disposed in the vicinity of the first side of the insulating base material  12  and are arranged in the X-axis direction. As illustrated in  FIG. 7B , the sixth interlayer connection conductors V 6  electrically connect the fifth ground conductor  35  and the third ground conductor  33  to each other. The sixth interlayer connection conductors V 6  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     A second signal line  42 , a first ground conductor  31 , a sixth ground conductor  36 , and the like are provided on the surface of the insulating base material  13 . The sixth ground conductor  36  is a conductor that is disposed in the vicinity of the second side (the upper side of the insulating base material  13  in  FIG. 7B ) of the insulating base material  13  and extends in the X-axis direction. The sixth ground conductor  36  is a conductor pattern made of a material such as a Cu foil, for example. 
     In addition, the insulating base material  13  includes a plurality of first interlayer connection conductors V 1 , a plurality of fourth interlayer connection conductors V 4 , and a plurality of fifth interlayer connection conductors V 5 . The fourth interlayer connection conductors V 4  are conductors that are disposed in the vicinity of the first side (the lower side of the insulating base material  13  in  FIG. 7B ) of the insulating base material  13  and are arranged in the X-axis direction. The plurality of fifth interlayer connection conductors V 5  are conductors that are disposed in the vicinity of the second side of the insulating base material  13  and are arranged in the X-axis direction. As illustrated in  FIG. 7B , the fourth interlayer connection conductors V 4  electrically connect the first ground conductor  31  and the fifth ground conductor  35  to each other. In addition, the fifth interlayer connection conductors V 5  electrically connect the sixth ground conductor  36  and the second ground conductor  32  to each other. The fourth interlayer connection conductors V 4  and the fifth interlayer connection conductors V 5  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     In addition, the insulating base material  14  includes a plurality of third interlayer connection conductors V 3 , and a plurality of seventh interlayer connection conductors V 7 . The seventh interlayer connection conductors V 7  are conductors that are disposed in the vicinity of the second side (the upper side of the insulating base material  14  in  FIG. 7B ) of the insulating base material  14  and are arranged in the X-axis direction. The seventh interlayer connection conductors V 7  electrically connect the fourth ground conductor  34  and the sixth ground conductor  36  to each other. The seventh interlayer connection conductors V 7  are, for example, via conductors or through holes of which an inner wall is plated, or the like. 
     As illustrated in  FIG. 7B  and  FIG. 8 , the fifth ground conductor  35  is provided on the same layer as the layer on which the first signal line  41  and the second ground conductor  32  are provided. In addition, the fifth ground conductor  35  extends in parallel or substantially in parallel with the first signal line  41 , and is disposed on an opposite side (the left side of the first signal line  41  in  FIG. 8 ) away from the second ground conductor  32  with respect to the first signal line  41 . 
     Further, as illustrated in  FIG. 7B  and  FIG. 8 , the sixth ground conductor  36  is provided on the same layer as the layer on which the second signal line  42  and the first ground conductor  31  are provided. In addition, the sixth ground conductor  36  extends in parallel or substantially in parallel with the second signal line  42 , and is disposed on an opposite side (the right side of the second signal line  42  in  FIG. 8 ) away from the first ground conductor  31  with respect to the second signal line  42 . 
     According to the multilayer substrate  103  of the third preferred embodiment of the present invention, the following advantageous effects in addition to the advantageous effects that have been described in the first preferred embodiment may be obtained. 
     In the third preferred embodiment, the ground conductors (the first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 , the fifth ground conductor  35 , the first interlayer connection conductor V 1 , the second interlayer connection conductor V 2 , the fourth interlayer connection conductor V 4 , and the sixth interlayer connection conductor V 6 ) are disposed in the surrounding four directions (the positive Y direction, the negative Y direction, the positive Z direction, and the negative Z direction with respect to the first signal line  41  in  FIG. 8 ) of the first signal line  41 , and the first signal line  41  is surrounded by the ground conductors in the surrounding four directions. In addition, in the third preferred embodiment, the ground conductors (the first ground conductor  31 , the second ground conductor  32 , the fourth ground conductor  34 , the sixth ground conductor  36 , the first interlayer connection conductor V 1 , the third interlayer connection conductor V 3 , the fifth interlayer connection conductor V 5 , and the seventh interlayer connection conductor V 7 ) are disposed in the surrounding four directions (the positive Y direction, the negative Y direction, the positive Z direction, and the negative Z direction with respect to the second signal line  42  in  FIG. 8 ) of the second signal line  42 , and the second signal line  42  is surrounded by the ground conductors in the surrounding four directions. Therefore, with this configuration, the isolation between the first signal line  41  and the second signal line  42  is further increased, and the effect of reducing cross talk is enhanced. 
     Fourth Preferred Embodiment 
     A fourth preferred embodiment of the present invention describes a multilayer substrate with a structure in which a plurality of transmission lines are branched at the first connection portion and the second connection portion. 
       FIG. 9  is a perspective view of a multilayer substrate  104  according to the fourth preferred embodiment of the present invention. 
     The multilayer substrate  104  includes a stacked body  10 B obtained by stacking a plurality of insulating base materials, and a conductor provided on any one of the plurality of insulating base materials. The multilayer substrate  104  is different from the multilayer substrate  101  according to the first preferred embodiment in that the multilayer substrate  104  includes a first connection portion CP 1  in which the first transmission line and the second transmission line are branched in a Y shape from the line portion SL, and a second connection portion CP 1  in which the first transmission line and the second transmission line are branched in a T shape from the line portion SL. Other configurations are substantially the same as the configurations of the multilayer substrate  101 . 
     As illustrated in  FIG. 9 , the first signal conductors  61  and  62 , the second signal conductors  71  and  72 , and the ground conductors  81 ,  82 ,  83 ,  84 ,  85 ,  86 ,  87 , and  88  are exposed on the first primary surface VS 1  of the stacked body  10 B. The first signal conductor  61  and the ground conductors  81  and  82  are connection portions of the first transmission line in the first connection portion CP 1 , and the second signal conductor  71  and the ground conductors  83  and  84  are connection portions of the second transmission line in the first connection portion CP 1 . In addition, the first signal conductor  62  and the ground conductors  85  and  86  are connection portions of the first transmission line in the second connection portion CP 2 , and the second signal conductor  72  and the ground conductors  87  and  88  are connection portions of the second transmission line in the second connection portion CP 2 . In the fourth preferred embodiment, each of the first signal conductors  61  and  62  corresponds to a “first external connection electrode”, and each of the second signal conductors  71  and  72  corresponds to a “second external connection electrode”. 
     As described above, a multilayer substrate according to a preferred embodiment of the present invention may include a structure in which a plurality of transmission lines are branched. It is to be noted that, while the fourth preferred embodiment of the present invention describes an example of a multilayer substrate in which the transmission line is branched into the first transmission line and the second transmission line, the present invention is not limited to such a configuration. As described in full detail later, in a case of a multilayer substrate including three or more transmission lines, the transmission lines may be branched into one transmission line and the other transmission lines. For example, in a case of a multilayer substrate including a first transmission line, a second transmission line, and a third transmission line, the transmission lines may be branched into the first transmission line and the second transmission line, and the third transmission line. 
     Fifth Preferred Embodiment 
     A fifth preferred embodiment of the present invention describes a multilayer substrate including two or more transmission lines. 
       FIG. 10  is a cross-sectional view of a line portion of a multilayer substrate  105  according to the fifth preferred embodiment of the present invention. 
     The multilayer substrate  105  includes a stacked body  10 C obtained by stacking a plurality of insulating base materials  11 ,  12 ,  13 ,  14 ,  15 , and  16 , a conductor (such as a first signal line  41 , a second signal line  42 , a third signal line  43 , a fourth signal line  44 , a fifth signal line  45 , a first ground conductor  31 , a second ground conductor  32 , a third ground conductor  33 , a fourth ground conductor  34 , a fifth ground conductor  35 , a sixth ground conductor  36 , a seventh ground conductor  37 , a first interlayer connection conductor V 1 , a second interlayer connection conductor V 2 , a third interlayer connection conductor V 3 , an eighth interlayer connection conductor V 8 , a ninth interlayer connection conductor V 9 , and a tenth interlayer connection conductor V 10 ) provided in any one of the plurality of insulating base materials  11 ,  12 ,  13 ,  14 ,  15 , and  16 , and protective layers  1  and  2 . 
     As illustrated in  FIG. 10 , the stacked body  10 C is obtained by stacking the insulating base materials  11 ,  12 ,  13 ,  14 ,  15 , and  16  in this order. The protective layer  1  is provided on the first primary surface VS 1  of the stacked body  10 C, and the protective layer  2  is provided on the second primary surface VS 2  of the stacked body  10 C. 
     As illustrated in  FIG. 10 , the first signal line  41 , the second signal line  42 , the third signal line  43 , the fourth signal line  44 , and the fifth signal line  45  are disposed at different layers, respectively, and extend in parallel or substantially in parallel with each other when viewed in the Z-axis direction. 
     In addition, as illustrated in  FIG. 10 , the first ground conductor  31  is provided on the same layer as the layer on which the second signal line  42  is provided, and is overlapped with the first signal line  41  and the third signal line  43  when viewed in the Z-axis direction. The second ground conductor  32  is provided on the same layer as the layer on which the first signal line  41  is provided, and is overlapped with the second signal line  42  and the fourth signal line  44  when viewed in the Z-axis direction. 
     The third ground conductor  33 , as illustrated in  FIG. 10 , is a conductor provided over substantially the entire surface of the second primary surface VS 2  of the stacked body  10 C. Therefore, the third ground conductor  33  is disposed to face the first ground conductor  31  across the first signal line  41  with respect to the Z-axis direction, and is disposed to face the second ground conductor  32  across the fourth signal line  44  with respect to the Z-axis direction. 
     The fourth ground conductor  34  is provided on a layer different from the layer on which the first ground conductor  31  is provided, and is disposed to face the second ground conductor  32  across the second signal line  42  with respect to the Z-axis direction. 
     The fifth ground conductor  35 , as illustrated in  FIG. 10 , is a conductor provided over substantially the entire surface of the first primary surface VS 1  of the stacked body  10 C. Therefore, the fifth ground conductor  35  is disposed to face the first ground conductor  31  across the third signal line  43  with respect to the Z-axis direction, and is disposed to face the fourth ground conductor  34  across the fifth signal line  45  with respect to the Z-axis direction. 
     The first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 , the fourth ground conductor  34 , the fifth ground conductor  35 , the sixth ground conductor  36 , and the seventh ground conductor  37  are electrically connected with each other through the interlayer connection conductors (the first interlayer connection conductor V 1 , the second interlayer connection conductor V 2 , the third interlayer connection conductor V 3 , the eighth interlayer connection conductor V 8 , the ninth interlayer connection conductor V 9 , and the tenth interlayer connection conductor V 10 ). 
     In the fifth preferred embodiment, the first signal line  41 , the first ground conductor  31 , the third ground conductor  33 , the insulating base material  13  interposed between the first signal line  41  and the first ground conductor  31 , and the insulating base materials  11  and  12  interposed between the first signal line  41  and the third ground conductor  33  define a first transmission line. In the fifth preferred embodiment, the second signal line  42 , the second ground conductor  32 , the fourth ground conductor  34 , the insulating base material  13  interposed between the second signal line  42  and the second ground conductor  32 , and the insulating base material  14  interposed between the second signal line  42  and the fourth ground conductor  34  define a second transmission line. 
     Further, in the fifth preferred embodiment, the third signal line  43 , the first ground conductor  31 , the fifth ground conductor  35 , the insulating base material  14  interposed between the third signal line  43  and the first ground conductor  31 , and the insulating base materials  15  and  16  interposed between the third signal line  43  and the fifth ground conductor  35  define a third transmission line. In the fifth preferred embodiment, the fourth signal line  44 , the second ground conductor  32 , the third ground conductor  33 , the insulating base material  12  interposed between the fourth signal line  44  and the second ground conductor  32 , and the insulating base material  11  interposed between the fourth signal line  44  and the third ground conductor  33  define a fourth transmission line. In the fifth preferred embodiment, the fifth signal line  45 , the fourth ground conductor  34 , the fifth ground conductor  35 , the insulating base material  15  interposed between the fifth signal line  45  and the fourth ground conductor  34 , and the insulating base material  16  interposed between the fifth signal line  45  and the fifth ground conductor  35  define a fifth transmission line. 
     In the fifth preferred embodiment, as illustrated in  FIG. 10 , the two insulating base materials  11  and  12  are interposed between the first signal line  41  and the third ground conductor  33 . Accordingly, in comparison with a configuration in which one insulating base material is interposed between a signal line and a ground conductor, a gap between the first signal line  41  and the third ground conductor  33  becomes large, so that capacitance to be generated between the first signal line  41  and the third ground conductor  33  is able to be reduced. Therefore, with this configuration, since a line width (the width in the Y-axis direction) of the first signal line  41  is able to be made larger than a line width of other signal transmission lines (the second signal line  42 , the fourth signal line  44 , and the fifth signal line  45 , for example), direct-current resistance of the first signal line  41  is able to be reduced. 
     Similarly, in the fifth preferred embodiment, as illustrated in  FIG. 10 , the two insulating base materials  15  and  16  are interposed between the third signal line  43  and the fifth ground conductor  35 . Therefore, with this configuration, since a line width (the width in the Y-axis direction) of the third signal line  43  is able to be made larger than a line width of other signal transmission lines (the second signal line  42 , the fourth signal line  44 , and the fifth signal line  45 , for example), direct-current resistance of the third signal line  43  is able to be reduced. 
     As illustrated in  FIG. 10 , in the fifth preferred embodiment, the protective layer  1  covers the entirety of the fifth ground conductor  35  provided over substantially the entire surface of the first primary surface VS 1  (the insulating base material  16 ) of the stacked body  10 C. Therefore, although the joining strength between the protective layer  1  and the stacked body  10 C is reduced and causes the protective layer  1  to become easily separated from the stacked body  10 C, even when the protective layer  1  is separated, a change in electrical characteristics of the multilayer substrate is small. 
     Similarly, in the fifth preferred embodiment, the protective layer  2  covers the entirety of the third ground conductor  33  provided over substantially the entire surface of the second primary surface VS 2  (the insulating base material  11 ) of the stacked body  10 C. Therefore, although the protective layer  2  becomes easily separated from the stacked body  10 C, even when the protective layer  2  is separated, the change in electrical characteristics of the multilayer substrate is small. 
     In addition, while the fifth preferred embodiment of the present provides an example of a multilayer substrate including five transmission lines, the present invention is not limited to such a configuration. The number of transmission lines that are provided on the multilayer substrate is able to be appropriately changed as long as the number is two or more. 
     Sixth Preferred Embodiment 
     A sixth preferred embodiment of the present invention describes a multilayer substrate including three transmission lines.  FIGS. 11A to 11D  are exploded plan views of a multilayer substrate  106  according to the sixth preferred embodiment of the present invention.  FIG. 12  is a cross-sectional view of the multilayer substrate  106  according to the sixth preferred embodiment of the present invention.  FIG. 12  illustrates a D-D cross-section illustrated in  FIGS. 11A to 11D . 
     The multilayer substrate  106  according to the sixth preferred embodiment is different from the multilayer substrate  101  according to the first preferred embodiment in that the multilayer substrate  106  further includes a third transmission line CL 3  in addition to the first transmission line CL 1  and the second transmission line CL 2 . The basic configuration such as a material of each component of the multilayer substrate  106  is the same as or similar to the configuration of the multilayer substrate  101  according to the first preferred embodiment, and a description of the same or similar configuration will be omitted. 
     The multilayer substrate  106  includes a stacked body  10 , a first ground conductor  31 , a second ground conductor  32 , a third ground conductor  33 , a fourth ground conductor  34 , an eighth ground conductor  38 , a first signal line  41 , a second signal line  42 , and a third signal line  43 . The multilayer substrate  106  includes first signal conductors  51  and  52  and external connection conductors  711 ,  712 ,  721 ,  722 ,  731 , and  732 . The stacked body  10  is obtained by stacking the insulating base materials  11 ,  12 ,  13 , and  14  in this order. 
     The third ground conductor  33  is provided on a surface of the insulating base material  11  on a side opposite to the insulating base material  12 . The third ground conductor  33  is provided on the entirety of the surface. 
     The first signal line  41 , the second ground conductor  32 , and the eighth ground conductor  38  are provided on the surface of the insulating base material  12  on the side of the insulating base material  13 . Each of the first signal line  41 , the second ground conductor  32 , and the eighth ground conductor  38  has a rectangular or substantially rectangular shape of which the X-axis direction is a longitudinal direction. The width (the length in the Y-axis direction) of the second ground conductor  32  is the same or substantially the same as the width (the length in the Y-axis direction) of the eighth ground conductor  38 . The width (the length in the Y-axis direction) of the first signal line  41  is smaller than the width of the second ground conductor  32  and the width of the eighth ground conductor  38 . 
     The first signal line  41 , the second ground conductor  32 , and the eighth ground conductor  38  are disposed at intervals in the Y-axis direction and extend in parallel or substantially in parallel with each other in the X-axis direction. In the Y-axis direction, the first signal line  41  is disposed between the second ground conductor  32  and the eighth ground conductor  38 . The second ground conductor  32  and the eighth ground conductor  38  are disposed at positions symmetric to each other with respect to a reference plane that extends through the center in the width direction of the first signal line  41  and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. It is to be noted that, in the cross-sectional view illustrated in  FIG. 12 , the second ground conductor  32  and the eighth ground conductor  38  are disposed at positions that are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the width direction of the first signal line  41 . This reference plane also means a reference plane that extends in the X-axis direction through the center in the width direction of the insulating base material  12 . 
     The second signal line  42 , the third signal line  43 , the first ground conductor  31 , and the first signal conductors  51  and  52  are provided on the surface of the insulating base material  13  on the side of the insulating base material  14 . 
     The second signal line  42 , the third signal line  43 , the first ground conductor  31  each have a rectangular or substantially rectangular shape of which the X-axis direction is a longitudinal direction. The width (the length in the Y-axis direction) of the second signal line  42  is the same or substantially the same as the width (length in the Y-axis direction) of the third signal line  43 . The width (the length in the Y-axis direction) of the first ground conductor  31  is larger than the width of the second signal line  42  and the width of the third signal line  43 . 
     The second signal line  42 , the third signal line  43 , and the first ground conductor  31  are disposed at intervals in the Y-axis direction and extend in parallel or substantially in parallel with each other in the X-axis direction. In the Y-axis direction, the first ground conductor  31  is disposed between the second signal line  42  and the third signal line  43 . The second signal line  42  and the third signal line  43  are disposed at positions symmetric to each other with respect to a reference plane that extends through the center in the width direction of the first ground conductor  31  and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. It is to be noted that, in the cross-sectional view illustrated in  FIG. 12 , the second signal line  42  and the third signal line  43  are disposed at positions that are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the width direction of the first ground conductor  31 . 
     As viewed in the stacking direction, the second signal line  42  is overlapped with the second ground conductor  32  over the entire length in the longitudinal direction (the X-axis direction). As viewed in the stacking direction, the third signal line  43  is overlapped with the eighth ground conductor  38  over the entire length in the longitudinal direction (the X-axis direction). 
     As viewed in the stacking direction, the first ground conductor  31  is overlapped with the first signal line  41  over the entire length in the longitudinal direction (the X-axis direction). Further, when viewed in the stacking direction, the first ground conductor  31  is overlapped with an end portion of the second ground conductor  32  on the side of the first signal line  41  and an end portion of the eighth ground conductor  38  on the side of the first signal line  41 . 
     Each of the first signal conductors  51  and  52  has a rectangular or substantially rectangular shape. As viewed in the stacking direction, the first signal conductor  51  is overlapped with one end portion of the first signal line  41  in the longitudinal direction (the X-axis direction), and the first signal conductor  52  is overlapped with the other end portion of the first signal line  41  in the longitudinal direction (the X-axis direction). 
     The fourth ground conductor  34  and the external connection conductors  711 ,  712 ,  721 ,  722 ,  731 , and  732  are provided on a surface of the insulating base material  14  on a side opposite to the insulating base material  13 . The fourth ground conductor is provided over substantially the entire surface of the insulating base material  14  on the side opposite to the insulating base material  13 . 
     The external connection conductors  711 ,  712 ,  721 ,  722 ,  731 , and  732  each have a rectangular or substantially rectangular shape, and are spaced from the fourth ground conductor  34  through opening portions (conductor-free portions) AP 11 , AP 12 , AP 21 , AP 22 , AP 31 , and AP 32 . 
     The external connection conductors  711 ,  721 , and  731  are provided in the vicinity of one end of the insulating base material  14  in the longitudinal direction (the X-axis direction). As viewed in the stacking direction, the external connection conductor  711  is overlapped with the first signal conductor  51 , the external connection conductor  721  is overlapped with the second signal line  42 , and the external connection conductor  731  is overlapped with the third signal line  43 . 
     The external connection conductors  712 ,  722 , and  732  are provided in the vicinity of the other end of the insulating base material  14  in the longitudinal direction (the X-axis direction). When viewed in the stacking direction, the external connection conductor  712  is overlapped with the first signal conductor  52 , the external connection conductor  722  is overlapped with the second signal line  42 , and the external connection conductor  732  is overlapped with the third signal line  43 . 
     The insulating base material  11  includes a plurality of interlayer connection conductors V 31 . A portion of the insulating base material  12  that is overlapped with the second ground conductor  32  and the eighth ground conductor  38  includes a plurality of second interlayer connection conductors V 2 . As viewed in the stacking direction, the arrangement pattern of the plurality of interlayer connection conductors V 31  is the same as the arrangement pattern of the plurality of second interlayer connection conductors V 2 , and an interlayer connection conductor V 31  and a second interlayer connection conductor V 2  at the same position are connected to each other. As a result, the second ground conductor  32  and the third ground conductor  33  are connected at a plurality of points, and the eighth ground conductor  38  and the third ground conductor  33  are connected at a plurality of points. 
     A portion of the insulating base material  13  that is overlapped with the first ground conductor  31  includes a plurality of first interlayer connection conductors V 1 . More specifically, when viewed in the stacking direction, the plurality of first interlayer connection conductors V 1  are provided in the portion with which the first ground conductor  31 , the second ground conductor  32 , and the eighth ground conductor  38  are overlapped. As a result, the first ground conductor  31  and the second ground conductor  32  are connected at a plurality of points, and the first ground conductor  31  and the eighth ground conductor  38  are connected at a plurality of points. 
     Further, when viewed in the stacking direction, the arrangement pattern of the plurality of first interlayer connection conductors V 1  is the same as the arrangement pattern of the plurality of interlayer connection conductors V 31  and the plurality of second interlayer connection conductors V 2 . 
     A portion of the insulating base material  13  that is overlapped with the first signal conductor  51  includes an interlayer connection conductor V 32 . As a result, the first signal conductor  51  and the first signal line  41  are connected. A portion of the insulating base material  13  that is overlapped with the first signal conductor  52  includes an interlayer connection conductor V 33 . As a result, the first signal conductor  52  and the first signal line  41  are connected. 
     A portion of the insulating base material  14  that is overlapped with the fourth ground conductor  34  includes a plurality of third interlayer connection conductors V 3 . More specifically, when viewed in the stacking direction, the plurality of third interlayer connection conductors V 3  are provided in the portion with which the fourth ground conductor  34  and the first ground conductor  31  are overlapped. As a result, the fourth ground conductor  34  and the first ground conductor  31  are connected at a plurality of points. 
     It is to be noted that, when viewed in the stacking direction, the plurality of third interlayer connection conductors V 3  are disposed at positions that are overlapped with at least positions on which the plurality of first interlayer connection conductors V 1  are disposed. Further, the plurality of third interlayer connection conductors V 3 , when viewed in the stacking direction, are disposed between the external connection conductors  721  and  731  and between the external connection conductors  722  and  732 , respectively. 
     Portions of the insulating base material  14  that are overlapped with the external connection conductors  711 ,  712 ,  721 ,  722 ,  731 , and  732  include interlayer connection conductors V 34 , V 35 , V 41 , V 42 , V 43 , and V 44 , respectively. As a result, the external connection conductor  711  is connected to the first signal conductor  51 , and the external connection conductor  712  is connected to the first signal conductor  52 . The external connection conductors  721  and  722  are connected to the second signal line  42 , and the external connection conductors  731  and  732  are connected to the third signal line  43 . 
     With use of such a configuration, the multilayer substrate  106  includes a first transmission line CL 1 , a second transmission line CL 2 , and a third transmission line CL 3 . The first transmission line CL 1  is provided by disposing the first signal line  41  between the first ground conductor  31  and the third ground conductor  33 . The second transmission line CL 2  is provided by disposing the second signal line  42  between the second ground conductor  32  and the fourth ground conductor  34 . The third transmission line CL 3  is provided by disposing the third signal line  43  between the fourth ground conductor  34  and the eighth ground conductor  38 . 
     As described above, since all of the first transmission line CL 1 , the second transmission line CL 2 , and the third transmission line CL 3  that are provided in the multilayer substrate  106  are structured such that a ground conductor is disposed on the both sides of a signal conductor in the stacking direction, the unnecessary radiation to the outside by all the transmission lines is significantly reduced or prevented reliably. 
     In addition, the multilayer substrate  106 , when viewed in the stacking direction, includes a third ground conductor  33  that is overlapped with all of the first signal line  41 , the second signal line  42 , and the third signal lines  43  on the second primary surface VS 2  of the stacked body  10 , and includes the fourth ground conductor  34  of the first primary surface VS 1  of the stacked body  10 . As a result, the unnecessary radiation to the outside is significantly reduced or prevented further reliably to all of the first transmission line CL 1 , the second transmission line CL 2 , and the third transmission line CL 3 . 
     In addition, in the multilayer substrate  106 , the first signal line  41  is disposed between the second ground conductor  32  and the eighth ground conductor  38  in the Y-axis direction, so that unnecessary radiation in the Y-axis direction is also significantly reduced or prevented. Further, in the Y-axis direction of the first signal line  41 , a plurality of interlayer connection conductors (the first interlayer connection conductor V 1 , the second interlayer connection conductor V 2 , the interlayer connection conductor V 31 ) arranged in the X-axis direction are disposed and are connected to the first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 , and the eighth ground conductor  38 , so that the unnecessary radiation in the Y-axis direction is further significantly reduced or prevented. 
     In addition, the first ground conductor  31  having a greater length in the Y-axis direction than the length of the second signal line  42  and the third signal line  43  is disposed between the second signal line  42  and the third signal line  43  in the Y-axis direction, so that higher isolation between the second signal line  42  and the third signal line  43  is able to be ensured. 
     In addition, in the multilayer substrate  106 , the second signal line  42  and the third signal line  43  are symmetric to each other with respect to a reference plane that extends through the center in the Y-axis direction (the width direction) of the multilayer substrate  106  and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. Further, the ground conductors configuring each transmission line are also arranged symmetric to each other with respect to the reference plane. Therefore, the second transmission line CL 2  and the third transmission line CL 3  are also symmetric with respect to the reference plane. As a result, structural and electromagnetic balance in the width direction (the Y-axis direction) in the multilayer substrate  106  is improved. In addition, with such a configuration, the occurrence of uneven irregularities on the surface (the first primary surface VS 1  or the second primary surface VS 2 ) of the multilayer substrate  106  is able to be significantly reduced or prevented, so that the bending workability of the multilayer substrate and the mounting performance of the multilayer substrate to be mounted on a circuit board or the like are improved. 
     Seventh Preferred Embodiment 
       FIGS. 13A to 13D  are exploded plan views of a multilayer substrate  107  according to a seventh preferred embodiment of the present invention. The multilayer substrate  107  according to the seventh preferred embodiment is different from the multilayer substrate  106  according to the sixth preferred embodiment in the configuration of a first ground conductor  31 F, a second signal line  42 F, and a third signal line  43 F. Other configurations of the multilayer substrate  107  are the same as or similar to the configurations of the multilayer substrate  106 , and a description of the same or similar configuration will be omitted. 
     The first ground conductor  31 F includes protruding portions  312 F and  313 F. The protruding portions  312 F and  313 F partially protrude in the Y-axis direction at predetermined positions in the X-axis direction of the first ground conductor  31 F. 
     The width (the length in the Y-axis direction) of the first ground conductor  31 F is smaller than the width of the first ground conductor  31  of the multilayer substrate  106  described in the sixth preferred embodiment (see  FIGS. 11A to 11D ). 
     The protruding portion  312 F protrudes to the side of the second signal line  42 F in the first ground conductor  31 F. The protruding portion  313 F protrudes to the side of the third signal line  43 F in the first ground conductor  31 F. 
     The second signal line  42 F includes a bent portion  420 F. The second signal line  42 F, as compared with the second signal line  42  of the multilayer substrate  106  illustrated in  FIGS. 11A to 11D , is disposed closer to the first ground conductor  31 F in the Y-axis direction, that is, to the center position in the insulating base material  13  in the Y-axis direction. Most of the second signal line  42 F in the longitudinal direction except the bent portion  420 F is overlapped with the protruding portion  312 F of the first ground conductor  31 F in the Y-axis direction. The bent portion  420 F is disposed along the outer periphery of the protruding portion  312 F. In other words, the bent portion  420 F, when viewed in the Z-axis direction, is provided in a shape that bypasses the protruding portion  312 F. 
     The third signal line  43 F includes a plurality of bent portions  430 F. The third signal line  43 F, as compared with the third signal line  43  of the multilayer substrate  106  illustrated in  FIGS. 11A to 11D , is disposed closer to the first ground conductor  31 F in the Y-axis direction, that is, to the center position in the insulating base material  13  in the Y-axis direction. Most of the third signal line  43 F in the longitudinal direction except the bent portion  430 F is overlapped with the protruding portion  313 F of the first ground conductor  31 F in the Y-axis direction. The bent portion  430 F is disposed along the outer periphery of the protruding portion  313 F. In other words, the bent portion  430 F, when viewed in the Z-axis direction, is provided in a shape that bypasses the protruding portion  313 F. 
     With such a configuration, the width (the length in the Y-axis direction) of the stacked body  10 , that is, the multilayer substrate  107 , is able to be reduced. 
     Eighth Preferred Embodiment 
       FIGS. 14A to 14D  are exploded plan views of a multilayer substrate  108  according to an eighth preferred embodiment of the present invention. The multilayer substrate  108  according to the eighth preferred embodiment is different from the multilayer substrate  106  according to the sixth preferred embodiment in the configuration of a first signal line  41 F, a second ground conductor  32 F, and an eighth ground conductor  38 F. Other configurations of the multilayer substrate  108  are the same as or similar to the configurations of the multilayer substrate  106 , and a description of the same or similar configuration will be omitted. 
     The second ground conductor  32 F includes a protruding portion  321 F. The protruding portion  321 F partially protrudes in the Y-axis direction at a predetermined position in the X-axis direction of the second ground conductor  32 F. The protruding portion  321 F protrudes to the side of the first signal line  41 F. 
     The eighth ground conductor  38 F includes a plurality of protruding portions  381 F. The plurality of protruding portions  381 F partially protrude in the Y-axis direction at predetermined positions in the X-axis direction of the eighth ground conductor  38 F. The plurality of protruding portions  381 F protrude to the side of the first signal line  41 F. 
     The first signal line  41 F includes bent portions  412 F and  413 F. The bent portion  412 F is disposed along the outer periphery of the protruding portions  381 F of the eighth ground conductor  38 F. In other words, the bent portion  412 F, when viewed in the Z-axis direction, is provided in a shape that bypasses the protruding portion  381 F. The bent portion  413 F is disposed along the outer periphery of the protruding portions  321 F of the second ground conductor  32 F. In other words, the bent portion  413 F, when viewed in the Z-axis direction, is provided in a shape that bypasses the protruding portion  321 F. 
     With such a configuration, in a similar manner to the multilayer substrate  107  according to the seventh preferred embodiment, the width (the length in the Y-axis direction) of the multilayer substrate  108 , that is, the stacked body  10 , is able to be reduced. 
     Ninth Preferred Embodiment 
       FIG. 15  is a cross-sectional view of a multilayer substrate  109  according to a ninth preferred embodiment of the present invention. The multilayer substrate  109  according to the ninth preferred embodiment is different from the multilayer substrate  106  according to the sixth preferred embodiment in that the multilayer substrate  109  further includes a fourth transmission line CL 4 . Other configurations of the multilayer substrate  109  are the same as or similar to the configurations of the multilayer substrate  106 , and a description of the same or similar configuration will be omitted. 
     The multilayer substrate  109 , in addition to the configuration of the multilayer substrate  106 , includes a fourth signal line  44 , ninth ground conductors  392  and  393 , and a plurality of interlayer connection conductors V 40 . The fourth signal line  44 , the ninth ground conductors  392  and  393 , and the plurality of interlayer connection conductors V 40  are provided in the stacked body  10 . 
     The fourth signal line  44  is provided between the first ground conductor  31  and the fourth ground conductor  34  in the Z-axis direction. The position of the fourth signal line  44  in the Y-axis direction is the same as the position of the first signal line  41 . The shape of the fourth signal line  44  is the same or substantially the same as the shape of the first signal line  41  except the end portions in the longitudinal direction. 
     The ninth ground conductor  392  is provided between the second signal line  42  and the fourth ground conductor  34  in the Z-axis direction. The position of the ninth ground conductor  392  in the Z-axis direction is the same or substantially the same as the position of the fourth signal line  44 . The position of the ninth ground conductor  392  in the Y-axis direction is the same or substantially the same as the position of the second ground conductor  32 . The shape of the ninth ground conductor  392  is the same or substantially the same as the shape of the second ground conductor  32 . 
     The ninth ground conductor  393  is provided between the third signal line  43  and the fourth ground conductor  34  in the Z-axis direction. The position of the ninth ground conductor  393  in the Z-axis direction is the same or substantially the same as the position of the fourth signal line  44 . The position of the ninth ground conductor  393  in the Y-axis direction is the same or substantially the same as the position of the eighth ground conductor  38 . The shape of the ninth ground conductor  393  is the same or substantially the same as the shape of the eighth ground conductor  38 . 
     The plurality of interlayer connection conductors V 40  are overlapped with the plurality of third interlayer connection conductors V 3  when the stacked body  10  is viewed in the Y-axis direction. The plurality of interlayer connection conductors V 40  electrically connect the ninth ground conductors  392  and  393  and the fourth ground conductor  34  to each other. In addition, the plurality of third interlayer connection conductors V 3  electrically connect the ninth ground conductors  392  and  393  and the first ground conductor  31  to each other. 
     With the configuration of the multilayer substrate  109  according to the ninth preferred embodiment, the multilayer substrate  109  includes a first transmission line CL 1 , a second transmission line CL 2 , a third transmission line CL 3 , and a fourth transmission line CL 4 . The first transmission line CL 1  is provided by disposing the first signal line  41  between the first ground conductor  31  and the third ground conductor  33 . The second transmission line CL 2  is provided by disposing the second signal line  42  between the second ground conductor  32  and the ninth ground conductor  392 . The third transmission line CL 3  is provided by disposing the third signal line  43  between the eighth ground conductor  38  and the ninth ground conductor  393 . The fourth transmission line CL 4  is provided by disposing the fourth signal line  44  between the first ground conductor  31  and the fourth ground conductor  34 . 
     With the configuration of the multilayer substrate  109  according to the ninth preferred embodiment, the following operational effect is able to be further obtained in addition to the operational effect obtained by the multilayer substrate  106 . 
     In the multilayer substrate  109 , the first signal line  41  and the fourth signal line  44  are symmetric to each other with respect to a reference plane that extends through the center in the Z-axis direction (the stacking direction) of the multilayer substrate  109  and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. It is to be noted that, in the cross-sectional view illustrated in  FIG. 15 , the first signal line  41  and the fourth signal line  44  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction (the stacking direction) of the multilayer substrate  109 . Further, the ground conductors of each transmission line are also disposed symmetric to each other with respect to the reference plane. Therefore, the first transmission line CL 1  and the fourth transmission line CL 4  are also symmetric with respect to the reference plane. As a result, structural (physical) balance in the stacking direction in the multilayer substrate  109  is improved and electromagnetic balance is also improved. 
     It is to be noted that the structural (physical) balance in the stacking direction is able to be improved, so that the occurrence of the uneven irregularities of the multilayer substrate is significantly reduced or prevented and the mounting performance of the multilayer substrate to be mounted on a circuit board or the like is improved. In addition, a warp in the stacking direction of the multilayer substrate  109  is significantly reduced or prevented from occurring. 
     Tenth Preferred Embodiment 
       FIG. 16  is a cross-sectional view of a multilayer substrate  110  according to a tenth preferred embodiment of the present invention. The multilayer substrate  110  according to the tenth preferred embodiment is different from the multilayer substrate  109  according to the ninth preferred embodiment in that the multilayer substrate  110  further includes a plurality of transmission lines CL 5  to CL 12 . Other basic configurations of the multilayer substrate  110  are the same as or similar to the basic configurations of the multilayer substrate  109 , and a description of the same or similar configuration will be omitted. 
     As illustrated in  FIG. 16 , the multilayer substrate  110  includes 12 signal lines  40 A,  40 B,  40 C,  40 D,  40 E,  40 F,  40 G,  40 H,  40 J,  40 K,  40 L, and  40 M, a first ground conductor  31 , a second ground conductor  32 , a third ground conductor  33 , a fourth ground conductor  34 , an eighth ground conductor  38 , and ninth ground conductors  392 ,  393 ,  394 ,  395 ,  3961 ,  3962 ,  397 ,  398 ,  3991 , and  3992 . 
     The signal lines  40 A and  40 E, the second ground conductor  32 , the eighth ground conductor  38 , and the ninth ground conductor  3961  are arranged side by side in the Y-axis direction. This layer is referred to as a first lateral conductor line layer. In such a case, the eighth ground conductor  38 , the signal line  40 A, the second ground conductor  32 , the signal line  40 E, and the ninth ground conductor  3961  are disposed in this order from a first end toward a second end of the Y-axis direction. 
     The signal lines  40 C,  40 B, and  40 E, the first ground conductor  31 , and the ninth ground conductor  395  are arranged side by side in the Y-axis direction. This layer is referred to as a second lateral conductor line layer. In such a case, the signal line  40 C, the first ground conductor  31 , the signal line  40 B, the ninth ground conductor  395 , and the signal line  40 F are disposed in this order from the first end toward the second end of the Y-axis direction. 
     The signal lines  40 D and  40 G, and the ninth ground conductors  392 ,  393 , and  3962  are arranged side by side in the Y-axis direction. This layer is referred to as a third lateral conductor line layer. In such a case, the ninth ground conductor  393 , the signal line  40 D, the ninth ground conductor  392 , the signal line  40 G, and the ninth ground conductor  3962  are disposed in this order from the first end toward the second end in the Y-axis direction. 
     The signal lines  40 H,  40 J, and  40 K, and the ninth ground conductors  394  and  397  are arranged side by side in the Y-axis direction. This layer is referred to as a fourth lateral conductor line layer. In such a case, the signal line  40 H, the ninth ground conductor  394 , the signal line  40 J, the ninth ground conductor  397 , and the signal line  40 K are disposed in this order from the first end toward the second end of the Y-axis direction. 
     The signal lines  40 L and  40 M, and the ninth ground conductors  398 ,  3991 , and  3992  are arranged side by side in the Y-axis direction. This layer is referred to as a fifth lateral conductor line layer. In such a case, the ninth ground conductor  398 , the signal line  40 L, the ninth ground conductor  3991 , the signal line  40 M, and the ninth ground conductor  3992  are disposed in this order from the first end toward the second end in the Y-axis direction. 
     The first lateral conductor line layer, the second lateral conductor line layer, the third lateral conductor line layer, the fourth lateral conductor line layer, and the fifth lateral conductor line layer are arranged in this order from the second primary surface VS 2  to the first primary surface VS 1  of the stacked body  10 . 
     The signal line  40 C and the signal line  40 H are disposed at positions that are overlapped with each other when viewed in the Z-axis direction. The signal line  40 A, the signal line  40 D, and the signal line  40 L are disposed at positions that are overlapped with each other when viewed in the Z-axis direction. The signal line  40 B and the signal line  40 J are disposed at positions that are overlapped with each other when viewed in the Z-axis direction. The signal line  40 E, the signal line  40 G, and the signal line  40 M are disposed at positions that are overlapped with each other, when viewed in the Z-axis direction. The signal line  40 F and the signal line  40 K are disposed at positions that are overlapped with each other when viewed in the Z-axis direction. 
     The first ground conductor  31  is disposed between the signal line  40 A and the signal line  40 D in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 A and the signal line  40 D when viewed in the Z-axis direction. 
     The second ground conductor  32  is disposed between the signal line  40 B and the third ground conductor  33  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 B and the third ground conductor  33  when viewed in the Z-axis direction. 
     The eighth ground conductor  38  is disposed between the signal line  40 C and the third ground conductor  33  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 C and the third ground conductor  33  when viewed in the Z axis direction. 
     The ninth ground conductor  392  is disposed between the signal line  40 B and the signal line  40 J in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 B and the signal line  40 J when viewed in the Z-axis direction. 
     The ninth ground conductor  393  is disposed between the signal line  40 C and the signal line  40 H in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 C and the signal line  40 H when viewed in the Z-axis direction. 
     The ninth ground conductor  394  is disposed between the signal line  40 D and the signal line  40 L in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 D and the signal line  40 L when viewed in the Z-axis direction. 
     The ninth ground conductor  395  is disposed between the signal line  40 E and the signal line  40 G in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 E and the signal line  40 G when viewed in the Z-axis direction. 
     The ninth ground conductor  3961  is disposed between the signal line  40 F and the third ground conductor  33  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 F and the third ground conductor  33  when viewed in the Z-axis direction. 
     The ninth ground conductor  3962  is disposed between the signal line  40 F and the signal line  40 K in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 F and the signal line  40 K when viewed in the Z-axis direction. 
     The ninth ground conductor  397  is disposed between the signal line  40 G and the signal line  40 M in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 G and the signal line  40 M when viewed in the Z-axis direction. 
     The ninth ground conductor  398  is disposed between the signal line  40 H and the fourth ground conductor  34  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 H and the fourth ground conductor  34  when viewed in the Z-axis direction. 
     The ninth ground conductor  3991  is disposed between the signal line  40 J and the fourth ground conductor  34  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 J and the fourth ground conductor  34  when viewed in the Z-axis direction. 
     The ninth ground conductor  3992  is disposed between the signal line  40 K and the fourth ground conductor  34  in the Z-axis direction of the stacked body  10 , and is overlapped with the signal line  40 K and the fourth ground conductor  34  when viewed in the Z-axis direction. 
     In other words, the 12 signal lines  40 A,  40 B,  40 C,  40 D,  40 E,  40 F,  40 G,  40 H,  40 J,  40 K,  40 L, and  40 M, the first ground conductor  31 , the second ground conductor  32 , the eighth ground conductor  38 , the ninth ground conductors  392 ,  393 ,  394 ,  395 ,  3961 ,  3962 ,  397 ,  398 ,  3991 , and  3992  are disposed alternately with each other in two dimensions of the Y-axis direction and the Z-axis direction in the stacked body  10 . Then, all of the 12 signal lines  40 A to  40 M, the first ground conductor  31 , the second ground conductor  32 , the eighth ground conductor  38 , the ninth ground conductors  392 ,  393 ,  394 ,  395 ,  3961 ,  3962 ,  397 ,  398 ,  3991 , and  3992  are overlapped with the third ground conductor  33  and the fourth ground conductor  34  when the stacked body  10  is viewed in the Z-axis direction. 
     The interlayer connection conductor V 11  is disposed between the positions of the signal lines  40 C and  40 H and the positions of the signal lines  40 A,  40 D, and  40 L in the Y-axis direction. One end in the direction in which the interlayer connection conductor V 11  extends is connected to the third ground conductor  33 , and the other end is connected to the fourth ground conductor  34 . The interlayer connection conductor V 11  is connected to the eighth ground conductor  38 , the first ground conductor  31 , the ninth ground conductor  393 , the ninth ground conductor  394 , and the ninth ground conductor  398 . 
     The interlayer connection conductor V 12  is disposed between the positions of the signal lines  40 A,  40 D, and  40 L and the positions of the signal lines  40 B and  40 J in the Y-axis direction. One end in the direction in which the interlayer connection conductor V 12  extends is connected to the third ground conductor  33 , and the other end is connected to the fourth ground conductor  34 . The interlayer connection conductor V 12  is connected to the second ground conductor  32 , the first ground conductor  31 , the ninth ground conductor  392 , the ninth ground conductor  394 , and the ninth ground conductor  3991 . 
     The interlayer connection conductor V 13  is disposed between the positions of the signal lines  40 B and  40 J and the positions of the signal lines  40 E,  40 G, and  40 M in the Y-axis direction. One end in the direction in which the interlayer connection conductor V 13  extends is connected to the third ground conductor  33 , and the other end is connected to the fourth ground conductor  34 . The interlayer connection conductor V 13  is connected to the second ground conductor  32 , the ninth ground conductor  395 , the ninth ground conductor  392 , the ninth ground conductor  397 , and the ninth ground conductor  3991 . 
     The interlayer connection conductor V 14  is disposed between the positions of the signal lines  40 E,  40 G, and  40 M and the positions of the signal lines  40 F and  40 K in the Y-axis direction. One end in the direction in which the interlayer connection conductor V 14  extends is connected to the third ground conductor  33 , and the other end is connected to the fourth ground conductor  34 . The interlayer connection conductor V 14  is connected to the ninth ground conductor  3961 , the ninth ground conductor  395 , the ninth ground conductor  3962 , the ninth ground conductor  397 , and the ninth ground conductor  3992 . 
     With such a configuration, the multilayer substrate  110  includes a first transmission line CL 1 , a second transmission line CL 2 , a third transmission line CL 3 , a fourth transmission line CL 4 , a fifth transmission line CL 5 , a sixth transmission line CL 6 , a seventh transmission line CL 7 , an eighth transmission line CL 8 , a ninth transmission line CL 9 , a tenth transmission line CL 10 , an eleventh transmission line CL 11 , and a twelfth transmission line CL 12 . 
     The first transmission line CL 1  is provided by disposing the signal line  40 A between the first ground conductor  31  and the third ground conductor  33 . The second transmission line CL 2  is provided by disposing the signal line  40 B between the second ground conductor  32  and the ninth ground conductor  392 . The third transmission line CL 3  is provided by disposing the signal line  40 C between the eighth ground conductor  38  and the ninth ground conductor  393 . The fourth transmission line CL 4  is provided by disposing the signal line  40 D between the first ground conductor  31  and the ninth ground conductor  394 . The fifth transmission line CL 5  is provided by disposing the signal line  40 E between the ninth ground conductor  395  and the third ground conductor  33 . The sixth transmission line CL 6  is provided by disposing the signal line  40 F between the ninth ground conductor  3961  and the ninth ground conductor  3962 . The seventh transmission line CL 7  is provided by disposing the signal line  40 G between the ninth ground conductor  395  and the ninth ground conductor  397 . The eighth transmission line CL 8  is provided by disposing the signal line  40 H between the ninth ground conductor  393  and the ninth ground conductor  398 . The ninth transmission line CL 9  is provided by disposing the signal line  40 J between the ninth ground conductor  392  and the ninth ground conductor  3991 . The tenth transmission line CL 10  is provided by disposing the signal line  40 K between the ninth ground conductor  3962  and the ninth ground conductor  3992 . The eleventh transmission line CL 11  is provided by disposing the signal line  40 L between the ninth ground conductor  394  and the fourth ground conductor  34 . The twelfth transmission line CL 12  is provided by disposing the signal line  40 M between the ninth ground conductor  397  and the fourth ground conductor  34 . 
     With the configuration of the multilayer substrate  110  according to the tenth preferred embodiment, all of the 12 transmission lines are disposed symmetrically (in line symmetry with respect to any one of dashed-dotted lines illustrated in  FIG. 16 ) with respect to any of the reference planes illustrated in  FIG. 16 . Further, the 12 transmission lines, in other words, the arrangement patterns of the entire transmission lines provided in the multilayer substrate  110  are symmetric with respect to a reference plane (a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J in  FIG. 16 ) that extends through the center of the Y-axis direction of the signal lines  40 B and  40 J and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction, and also with respect to a reference plane (a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 D and  40 G in  FIG. 16 ) that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. 
     Specifically, the following symmetric patterns are obtained in the Y-axis direction. The first transmission line CL 1  and the fifth transmission line CL 5  extend through the center of the Y-axis direction of the signal lines  40 B and  40 J, and are symmetric with respect to a reference plane in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the first transmission line CL 1  and the fifth transmission line CL 5  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J. The fourth transmission line CL 4  and the seventh transmission line CL 7  extend through the center of the Y-axis direction of the signal lines  40 B and  40 J, and are symmetric with respect to a reference plane that extends in the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the fourth transmission line CL 4  and the seventh transmission line CL 7  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J. The eleventh transmission line CL 11  and the twelfth transmission line CL 12  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 B and  40 J and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the eleventh transmission line CL 11  and the twelfth transmission line CL 12  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J. 
     The third transmission line CL 3  and the second transmission line CL 2  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 A,  40 D, and  40 L and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the third transmission line CL 3  and the second transmission line CL 2  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 A,  40 D, and  40 L. The second transmission line CL 2  and the sixth transmission line CL 6  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 E,  40 G, and  40 M and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the second transmission line CL 2  and the sixth transmission line CL 6  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 E,  40 G, and  40 L. The third transmission line CL 3  and the sixth transmission line CL 6  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 B and  40 J and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the third transmission line CL 3  and the sixth transmission line CL 6  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J. 
     The eighth transmission line CL 8  and the ninth transmission line CL 9  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 A,  40 D, and  40 L and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the eighth transmission line CL 8  and the ninth transmission line CL 9  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 A,  40 D, and  40 L. The ninth transmission line CL 9  and the tenth transmission line CL 10  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 E,  40 G, and  40 M and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the ninth transmission line CL 9  and the tenth transmission line CL 10  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 E,  40 G, and  40 M. The eighth transmission line CL 8  and the tenth transmission line CL 10  are symmetric with respect to a reference plane that extends through the center of the Y-axis direction of the signal lines  40 B and  40 J and is in parallel or substantially in parallel to the X-axis direction and the Z-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the eighth transmission line CL 8  and the tenth transmission line CL 10  are in line symmetry with respect to a dashed-dotted line that extends in the Z-axis direction through the center in the Y-axis direction of the signal lines  40 B and  40 J. 
     In addition, the following symmetric patterns are obtained in the Z-axis direction. The third transmission line CL 3  and the eighth transmission line CL 8  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the third transmission line CL 3  and the eighth transmission line CL 8  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 D and  40 G. The second transmission line CL 2  and the ninth transmission line CL 9  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the second transmission line CL 2  and the ninth transmission line CL 9  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 D and  40 G. The sixth transmission line CL 6  and the tenth transmission line CL 10  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the sixth transmission line CL 6  and the tenth transmission line CL 10  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 D and  40 G. 
     The first transmission line CL 1  and the fourth transmission line CL 4  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 C,  40 B, and  40 F and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the first transmission line CL 1  and the fourth transmission line CL 4  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 C,  40 B, and  40 F. The fourth transmission line CL 4  and the eleventh transmission line CL 11  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 H,  40 J, and  40 K and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the fourth transmission line CL 4  and the eleventh transmission line CL 11  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 C,  40 B, and  40 F. The first transmission line CL 1  and the eleventh transmission line CL 11  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the first transmission line CL 1  and the eleventh transmission line CL 11  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 C,  40 B, and  40 F. 
     The fifth transmission line CL 5  and the seventh transmission line CL 7  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 C,  40 B, and  40 F and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the fifth transmission line CL 5  and the seventh transmission line CL 7  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 C,  40 B, and  40 F. The seventh transmission line CL 7  and the twelfth transmission line CL 12  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 H,  40 J, and  40 K, and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the seventh transmission line CL 7  and the twelfth transmission line CL 12  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 H,  40 J, and  40 K. The fifth transmission line CL 5  and the twelfth transmission line CL 12  are symmetric with respect to a reference plane that extends through the center of the Z-axis direction of the signal lines  40 D and  40 G and is in parallel or substantially in parallel to the X-axis direction and the Y-axis direction. In the cross-sectional view illustrated in  FIG. 16 , the fifth transmission line CL 5  and the twelfth transmission line CL 12  are in line symmetry with respect to a dashed-dotted line that extends in the Y-axis direction through the center in the Z-axis direction of the signal lines  40 D and  40 G. 
     As a result, in a similar manner to the multilayer substrate  109 , structural and electromagnetic balance in the multilayer substrate  110  is improved. 
     It is to be noted that, while the tenth preferred embodiment of the present invention describes the example in which the 12 transmission lines are provided in the stacked body  10 , more than 12 transmission lines may be able to be provided in the stacked body  10  by a similar configuration. 
     In addition, although described above, by using the multilayer substrate described in each preferred embodiment, an electronic device as illustrated in  FIG. 17  is able to be obtained.  FIG. 17  is an external perspective view of an electronic device  202  according to the tenth preferred embodiment of the present invention. It is to be noted that, while  FIG. 17  illustrates the example in which the multilayer substrate  106  is used, the multilayer substrates according to other preferred embodiments are also able to provide a similar structure. 
     The electronic device  202  includes a multilayer substrate  106 , a circuit board  302 , and a plurality of mounted components  320 . The multilayer substrate  106  and the plurality of mounted components  320  are mounted on the surface of the circuit board  302 . The multilayer substrate  106  is disposed such that the first primary surface VS 1  faces the surface of the circuit board  302 . Each of the external connection conductors of the multilayer substrate  106  is joined to a land conductor provided on the surface of the circuit board  302 . In such a case, each of the external connection conductors is joined to a land conductor only through a conductive joining material such as solder. In other words, the multilayer substrate  106  is surface-mounted on the circuit board  302 . 
     As described above, when the multilayer substrate  106  is surface-mounted on the circuit board  302 , the distance between the multilayer substrate  106  and the surface of the circuit board  302  becomes smaller as compared with an example in which a connector or the like is used. However, as described above, the multilayer substrate  106  includes a fourth ground conductor  34  on the first primary surface VS 1 , the fourth ground conductor  34  being overlapped with all the signal lines in the stacked body  10  (see  FIG. 12 ). Therefore, unnecessary radiation from the multilayer substrate  106  to the circuit board  302  is significantly reduced or prevented. As a result, electromagnetic coupling between the multilayer substrate  106  and the circuit board  302  is significantly reduced or prevented. In addition, the fourth ground conductor  34  that is overlapped with all the signal lines in the stacked body  10  is provided, so that the occurrence of the uneven irregularities of the surface (the first primary surface VS 1  or the second primary surface VS 2 ) of the multilayer substrate  106  is significantly reduced or prevented, and the mounting performance during surface-mounting to the circuit board  302  or the like is improved. 
     Eleventh Preferred Embodiment 
       FIG. 18A  is a cross-sectional view of a multilayer substrate  111  according to an eleventh preferred embodiment of the present invention, and  FIG. 18B  is an enlarged cross-sectional view of a ZP portion in  FIG. 18A . The multilayer substrate  111  according to the eleventh preferred embodiment is different from the multilayer substrate  106  according to the sixth preferred embodiment in that the multilayer substrate  111  includes first intermediate ground conductors M 31 A and M 31 B, and second intermediate ground conductors M 32 A and M 32 B. In addition, the stacked body  10  of the multilayer substrate  111  is different from the multilayer substrate  106  in that five insulating base materials are stacked. Other configurations of the multilayer substrate  111  are substantially the same as the configurations of the multilayer substrate  106 , and a description of the same or similar configuration will be omitted. 
     As illustrated in  FIG. 18A , the first intermediate ground conductor M 31 A is provided between a layer on which a first signal line  41  is provided and a layer on which a second signal line  42  is provided, in the stacking direction (the Z-axis direction). The first intermediate ground conductor M 31 A is disposed between the first signal line  41  and the second signal line  42  when viewed in the stacking direction. The first intermediate ground conductor M 31 A continuously extends in parallel or substantially in parallel with the first signal line  41  and the second signal line  42  (not illustrated). At least a portion of the first intermediate ground conductor  31 A is overlapped with a first ground conductor  31 , a second ground conductor  32 , a third ground conductor  33 , and a fourth ground conductor  34  when viewed in the stacking direction. The first intermediate ground conductor M 31 A is connected to the first ground conductor  31  through an interlayer connection conductor V 1 A, and is connected to the second ground conductor  32  through an interlayer connection conductor V 1 B. 
     The first intermediate ground conductor M 31 B is provided between the layer on which the first signal line  41  is provided and a layer on which a third signal line  43  is provided, with respect to the stacking direction. The first intermediate ground conductor M 31 B is disposed between the first signal line  41  and the third signal line  43  when viewed in the stacking direction. The first intermediate ground conductor M 31 B continuously extends in parallel or substantially in parallel with the first signal line  41  and the third signal line  43  (not illustrated). At least a portion of the first intermediate ground conductor  31 B is overlapped with the first ground conductor  31 , the third ground conductor  33 , the fourth ground conductor  34 , and an eighth ground conductor  38  when viewed in the stacking direction. The first intermediate ground conductor M 31 B is connected to the first ground conductor  31  through the interlayer connection conductor V 1 A, and is connected to the eighth ground conductor  38  through the interlayer connection conductor V 1 B. 
     Hereinafter, although only the first intermediate ground conductor M 31 A is mainly described, the first intermediate ground conductor M 31 B also has the same or substantially the same configuration. 
     As illustrated in  FIG. 18B , the first intermediate ground conductor M 31 A extends farther toward the first signal line than to the second ground conductor  32  when viewed in the stacking direction, and includes a portion that is not overlapped with the second ground conductor  32 . It is to be noted that the first intermediate ground conductor M 31 A is spaced farther apart from the first signal line  41  than at least one of the other ground conductors (such as the first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 ). Specifically, as illustrated in  FIG. 18B , when a distance between the first signal line  41  and the first ground conductor  31  is indicated by L 11 , a distance between the first signal line  41  and the second ground conductor  32  is indicated by L 12 , a distance between the first signal line  41  and the third ground conductor  33  is indicated by L 13 , and a distance between the first signal line  41  and the first intermediate ground conductor M 31 A is indicated by LM 1 , the distance LM 1  is larger than any one of the distances L 11 , L 12 , and L 13 . 
     In addition, as illustrated in  FIG. 18B , the first intermediate ground conductor M 31 A extends farther toward the second signal line  42  than to the first ground conductor  31  when viewed in the stacking direction, and includes a portion that is not overlapped with the first ground conductor  31 . It is to be noted that the first intermediate ground conductor M 31 A is spaced farther apart from the second signal line  42  than at least one of the other ground conductors (such as the first ground conductor  31 , the second ground conductor  32 , the fourth ground conductor  34 ). Specifically, as illustrated in  FIG. 18B , when a distance between the second signal line  42  and the first ground conductor  31  is indicated by L 21 , a distance between the second signal line and the second ground conductor  32  is indicated by L 22 , a distance between the second signal line  42  and the fourth ground conductor  34  is indicated by L 24 , and a distance between the second signal line  42  and the first intermediate ground conductor M 31 A is indicated by LM 2 , the distance LM 2  is larger than any one of the distances L 21 , L 22 , and L 24 . 
     Further, the thickness of the first intermediate ground conductor M 31 A in the stacking direction is thinner than the thickness of the other ground conductors (the first ground conductor  31 , the second ground conductor  32 , the third ground conductor  33 , and the fourth ground conductor  34 ) in the stacking direction. 
     As illustrated in  FIGS. 18A and 18B , the second intermediate ground conductor M 32 A is provided between the layer on which the first signal line  41  is provided and the second primary surface VS 2 , with respect to the stacking direction. The second intermediate ground conductor M 32 A continuously extends in parallel or substantially in parallel with the first signal line (not illustrated). The second intermediate ground conductor M 32 A is connected to the second ground conductor  32  through an interlayer connection conductor V 2 A, and is connected to the third ground conductor  33  through an interlayer connection conductor V 2 B. 
     The second intermediate ground conductor M 32 B is provided between the layer on which the first signal line  41  is provided and the second primary surface VS 2 , with respect to the stacking direction. The second intermediate ground conductor M 32 B continuously extends in parallel or substantially in parallel with the first signal line  41  (not illustrated). The second intermediate ground conductor M 32 B is connected to the eighth ground conductor  38  through the interlayer connection conductor V 2 A, and is connected to the third ground conductor  33  through an interlayer connection conductor V 2 B. 
     According to the multilayer substrate  111  according to the eleventh preferred embodiment, the following operational effect is able to be further obtained. 
     In the multilayer substrate  111 , the first intermediate ground conductor M 31 A is provided between the layer on which the first signal line  41  is provided and the layer on which the second signal line  42  is provided, with respect to the stacking direction. In addition, the first intermediate ground conductor M 31 A is disposed between the first signal line  41  and the second signal line  42  when viewed in the stacking direction. With this configuration, the isolation between the first signal line  41  and the second signal line  42  is further increased, and the effect of reducing cross talk is further enhanced. It is to be noted that, in the eleventh preferred embodiment, the first intermediate ground conductor M 31 B is provided, so that the isolation between the first signal line  41  and the third signal line  43  is further increased, and the effect of reducing cross talk is further enhanced. 
     In addition, in the eleventh preferred embodiment, the first intermediate ground conductor M 31 A extends farther toward the first signal line  41  than to the second ground conductor  32  when viewed in the stacking direction, and includes a portion that is not overlapped with the second ground conductor  32 . With this configuration, since the first intermediate ground conductor M 31 A is disposed closer to the first signal line  41 , the magnetic field to be generated around the first signal line  41  is effectively shielded, and the isolation between the first signal line  41  and the second signal line  42  is able to be further increased. 
     It is to be noted that, in the eleventh preferred embodiment, the first intermediate ground conductor M 31 A is spaced farther apart from the first signal line  41  than at least one of the other ground conductors. Therefore, the isolation between the first signal line  41  and the second signal line  42  is able to be increased without greatly affecting capacitance to be generated between the first signal line  41  and the other ground conductors. 
     In addition, in the eleventh preferred embodiment, the first intermediate ground conductor M 31 A extends farther toward the second signal line  42  than to the first ground conductor  31  when viewed in the stacking direction, and includes a portion that is not overlapped with the first ground conductor  31 . With this configuration, since the first intermediate ground conductor M 31 A is disposed closer to the second signal line  42 , the magnetic field to be generated around the second signal line  42  is effectively shielded, and the isolation between the first signal line  41  and the second signal line  42  is able to be further increased. 
     It is to be noted that, in the eleventh preferred embodiment, the first intermediate ground conductor M 31 A is spaced farther apart from the second signal line  42  than at least one of the other ground conductors. Therefore, the isolation between the first signal line  41  and the second signal line  42  is able to be increased without greatly affecting capacitance to be generated between the second signal line  42  and the other ground conductors. 
     Further, the thickness of the first intermediate ground conductors M 31 A and M 31 B in the stacking direction is thinner than the thickness of the other ground conductors in the stacking direction. Since the first intermediate ground conductors M 31 A and M 31 B are disposed at positions that are overlapped with a large number of conductors in the stacking direction, in the eleventh preferred embodiment, irregularities are easily formed on the surface of the multilayer substrate after the stacked body  10  is obtained. However, with this configuration, irregularities are able to be significantly reduced or prevented from being formed on the surface of the multilayer substrate. 
     By using the multilayer substrate  111  according to the eleventh preferred embodiment, the following electronic device is able to be obtained.  FIG. 19  is an external perspective view of an electronic device  203  according to the eleventh preferred embodiment of the present invention. 
     The electronic device  203  includes a multilayer substrate  111 A and a circuit board  303 . 
     The multilayer substrate  111 A is different from the multilayer substrate  111  in that the multilayer substrate  111 A includes a protective layer  2  on the second primary surface VS 2 . Other configurations of the multilayer substrate  111 A are the same or substantially the same as the configurations of the multilayer substrate  111 . The protective layer  2  includes an opening, and the protective layer  2  is provided on the second primary surface VS 2 , so that a portion of the third ground conductor  33  is exposed. The surface of the circuit board  303  includes a conductor  95 , and the inside of the circuit board  303  includes conductors  96  and  97  and the like. 
     The multilayer substrate  111 A is disposed such that the second primary surface VS 2  faces the surface of the circuit board  303 . As illustrated in  FIG. 19 , the third ground conductor  33  of the multilayer substrate  111 A is joined to the circuit board  303  through a conductive joining material  4  such as solder. In other words, the multilayer substrate  111 A is surface-mounted on the circuit board  303 . 
     Therefore, among the first signal line  41 , the second signal line  42 , and the third signal line  43 , the first signal line  41  is disposed closest to the mounting surface (the front surface) of the circuit board  303 . In addition, the second intermediate ground conductors M 32 A and M 32 B are provided, in the stacking direction (the Z-axis direction), between the mounting surface and the layer on which the first signal line  41  is provided. 
     With the configuration of the electronic device  203  according to the eleventh preferred embodiment, the following operational effect is able to be further obtained in addition to the operational effect obtained by the electronic device  202  described in the tenth preferred embodiment. Hereinafter, although only the second intermediate ground conductor M 32 A is mainly described, the second intermediate ground conductor M 32 B also has the same or substantially the same configuration. 
     In the electronic device  203 , among the first signal line  41 , the second signal line  42 , and the third signal line  43 , the first signal line  41  is disposed closest to the mounting surface of the circuit board  303 . In addition, the second intermediate ground conductors M 32 A is provided, with respect to the stacking direction, between the mounting surface of the circuit board  303  and the layer on which the first signal line  41  is provided. In addition, the second intermediate ground conductor M 32 A is disposed between the first signal line  41  and the second signal line  42  (side of the positive Y direction of the first signal line  41 ), when viewed in the stacking direction. With this configuration, by the magnetic field to be generated around the first signal line  41 , coupling between the first signal line  41  and the conductors provided in contact with the circuit board  303  is significantly reduced or prevented (see the magnetic flux φ 1  to be generated around the first signal line  41  illustrated in  FIG. 19 ). 
     In addition, in the eleventh preferred embodiment, the second intermediate ground conductor M 32 A extends farther toward the first signal line  41  than to the second ground conductor  32  when viewed in the stacking direction, and includes a portion that is not overlapped with the second ground conductor  32 . With this configuration, since the second intermediate ground conductor M 32 A is disposed closer to the first signal line  41 , the magnetic field to be generated around the first signal line  41  is effectively shielded, and the coupling between the first signal line  41  and the conductors provided in contact with the circuit board  303  is able to be significantly reduced or prevented. 
     Further, in the eleventh preferred embodiment, the second intermediate ground conductor M 32 A is spaced farther apart from the first signal line  41  than at least one of the other ground conductors. Therefore, the coupling between the first signal line  41  and the conductors provided in contact with the circuit board  303  is able to be significantly reduced or prevented without greatly affecting capacitance to be generated between the first signal line  41  and the other ground conductors. 
     In addition, the thickness of the second intermediate ground conductors M 32 A and M 32 B in the stacking direction is thinner than the thickness of the other ground conductors in the stacking direction. Since the second intermediate ground conductors M 32 A and M 32 B are disposed at positions that are overlapped with a large number of conductors in the stacking direction, in the eleventh preferred embodiment, irregularities are easily formed on the surface of the multilayer substrate after the stacked body  10  is obtained. However, according to this configuration, irregularities are able to be significantly reduced or prevented from being formed on the surface of the multilayer substrate. 
     It is to be noted that, while the eleventh preferred embodiment has described the example in which the first intermediate ground conductors M 31 A and M 31 B and the second intermediate ground conductors M 32 A and M 32 B continuously extend in parallel or substantially in parallel with each other along the first signal line  41  and the second signal line  42 , the present invention is not limited to such a configuration. The first intermediate ground conductors and the second intermediate ground conductors may intermittently extend in parallel or substantially in parallel with the first signal line  41  and the second signal line  42 . In such a case, the first intermediate ground conductors and the second intermediate ground conductors may preferably be connected to another ground conductor by the interlayer connection conductor or the like. 
     Other Preferred Embodiments 
     While each of the above described preferred embodiments is an example in which a stacked body has a rectangular or substantially rectangular parallelepiped shape, the present invention is not limited to such a configuration. The plane shape of the stacked body is not limited to a rectangle or substantially a rectangle and is able to be appropriately changed in the range in which the functions and effects of preferred embodiments of the present invention are obtained. The plane shape of the stacked body may be a circle, an ellipse, a polygon, an L shape, a crank shape, a T shape, or a Y shape, for example. 
     While each of the above described preferred embodiments has described the multilayer substrate provided with the stacked body obtained by stacking two, four, or six insulating base materials, the present invention is not limited to such a configuration. The number of layers of insulating base materials to obtain the stacked body is able to be appropriately changed in the range in which the functions and effects of preferred embodiments of the present invention are obtained. 
     In addition, while each of the above described preferred embodiments has described the multilayer substrate in which the protective layer  1  is provided only on the first primary surface VS 1  of the stacked body or the multilayer substrate in which the protective layers  1  and  2  are provided on both the first primary surface VS 1  and second primary surface VS 2  of the stacked body, the present invention is not limited to such a configuration. The multilayer substrate may be a multilayer substrate in which the protective layer is provided only on the second primary surface VS 2  of the stacked body. It is to be noted that, in the multilayer substrate according to preferred embodiments of the present invention, a protective layer is not essential. 
     While each of the above described preferred embodiments has described the example in which the connection portions (the first connection portion CP 1  and the second connection portion CP 2 ) are provided in the vicinity of the end portions (the first end portion and the second end portion) in the longitudinal direction of the stacked body, the present invention is not limited to such a configuration. The positions of the connection portions are able to be appropriately changed within the scope of operations and features of the preferred embodiments of the present invention, the connection portions may be provided in the vicinity of the center in the longitudinal direction of the stacked body, for example. 
     While each of the above described preferred embodiments has described the multilayer substrate in which the connection portions (the first connection portion CP 1  and the second connection portion CP 2 ) are provided only on the first primary surface VS 1  of the stacked body  10 , the present invention is not limited to such a configuration. The multilayer substrate may be a multilayer substrate in which the connection portion is provided only on the second primary surface VS 2  of the stacked body. In addition, the multilayer substrate may be a multilayer substrate in which the connection portion is provided on both the first primary surface VS 1  and second primary surface VS 2  of the stacked body. 
     While each of the above described preferred embodiments has described the multilayer substrate in which the first connection portion CP 1 , the line portion SL, and the second connection portion CP 2  are disposed in this order in the X-axis direction, the present invention is not limited to such a configuration. The arrangement of the connection portions (the first connection portion CP 1 , the second connection portion CP 2 , and the like) and the line portion SL is able to be appropriately changed in the range in which the functions and effects of preferred embodiments of the present invention are obtained. In addition, while each of the above described preferred embodiments has described the example in which the line portion SL (the first signal line  41 , the second signal line  42 , and the like) is a conductor extending in the X-axis direction, the present invention is not limited to such a configuration. The line portion (the first signal line  41 , the second signal line  42 , and the like) does not necessarily need to have a linear shape extending in the X-axis direction, and may bend in the Y-axis direction, for example. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.