TRANSMISSION LINE

A transmission line includes a substrate, a high-frequency signal transmission line, a differential signal transmission line, and a power supply line. The substrate is insulating, extends in a predetermined direction, and internally includes each of the high-frequency signal transmission line, the differential signal transmission line, and the power supply line. The power supply line and the high-frequency signal transmission line are in parallel or substantially in parallel to each other, and the differential signal transmission line is between the power supply line and the high-frequency signal transmission line.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transmission line including a high-frequency signal transmission line and a power supply line.

2. Description of the Related Art

WO 2016/163436 A discloses a multilayer resin flexible cable where a high-frequency signal transmission line, a differential signal line, and a power supply line are built in a single substrate.

The multilayer resin flexible cable disclosed in WO 2016/163436 A includes an insulating substrate. The insulating substrate has a first region and a second region in a width direction of the insulating substrate. The first region includes the high-frequency signal transmission line and the differential signal line. The second region includes the power supply line. The high-frequency signal transmission line and the differential signal line are arranged and aligned in a thickness direction of the insulating substrate.

However, in a configuration disclosed in WO 2016/163436 A, the power supply line and the high-frequency signal transmission line adjoin each other. Thus, a noise flowing in the power supply line is prone to propagate to the high-frequency signal transmission line.

Here, a fault caused by the noise overlapping a high-frequency signal is prone to occur.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide transmission lines in each of which noise from a power supply line is less prone to propagate to a high-frequency signal transmission line.

A preferred embodiment of the present invention provides a transmission line including a substrate, a high-frequency signal transmission line, a differential signal transmission line, and a power supply line. The substrate is insulating, extends in a predetermined direction, and internally includes each of the high-frequency signal transmission line, the differential signal transmission line, and the power supply line. The power supply line and the high-frequency signal transmission line are in parallel or substantially in parallel to each other, and the differential signal transmission line is between the power supply line and the high-frequency signal transmission line.

Here, the power supply line and the high-frequency signal transmission line are spaced away from each other. Thus, a noise from the power supply line is less prone to propagate to the high-frequency signal transmission line. Further, the differential signal transmission line is between the power supply line and the high-frequency signal transmission line, such that the noise is even less prone to propagate to the high-frequency signal transmission line. In this state, the differential signal transmission line has higher noise resistance than the high-frequency signal transmission line. Accordingly, the differential signal transmission line is less prone to being affected by the noise, thus resulting in less influence on transmission of the differential signal.

Preferred embodiments of the present invention provide transmission lines in each of which a noise from a power supply line is less prone to propagate to a high-frequency signal transmission line.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

A transmission line according to a first preferred embodiment of the present invention will be described with reference to the drawings.FIG. 1is a cross-sectional view showing a transmission line100according to the first preferred embodiment of the present invention.FIG. 2is a perspective view showing a portion of the transmission line100according to the first preferred embodiment of the present invention.FIG. 3Ais a plan view of an electronic device900including the transmission line100according to the first preferred embodiment of the present invention.FIG. 3Bis a cross-sectional side view showing the electronic device900including the transmission line100according to the first preferred embodiment of the present invention.FIG. 4is a block diagram showing circuitry of the electronic device900including the transmission line100according to the first preferred embodiment of the present invention. Note that, in each of the drawings, a thickness is exaggerated for convenience of description.

As shown inFIGS. 1 and 2, the transmission line100includes a substrate101, a high-frequency signal transmission line10, a power supply line20, and a differential signal transmission line30.

The substrate101is a flat plate extending in a predetermined direction (X-axis direction in the drawing ofFIG. 2). In a thickness direction of the substrate101(Z-axis direction on the drawing of each ofFIGS. 1 and 2), the substrate101includes, at one end, a first main surface102and includes, at another end, a second main surface103. In perpendicular or substantially in perpendicular to a width direction of the substrate101(Y-axis direction in the drawing of each ofFIGS. 1 and 2), the substrate101includes, at one end, a side surface104and includes, at another end, a side surface105. Note that, the substrate101is not limited to a linear shape, but may include, for example, a bent section or a curved section in plan view.

The substrate101includes an insulating resin material that may be curved or bent in a direction perpendicular or substantially perpendicular to each of the first main surface102and the second main surface103. The substrate101mainly includes, for example, a liquid crystal polymer.

The substrate101includes the high-frequency signal transmission line10adjacent to or in the vicinity of the side surface104. The high-frequency signal transmission line10includes a signal conductor11, a ground conductor12, and a ground conductor13. Each of the signal conductor11, the ground conductor12, and the ground conductor13extends in the direction where the substrate101extends.

The signal conductor11is positioned substantially at a center of the substrate101in the thickness direction of the substrate101. The ground conductor12is located on the first main surface102of the substrate101, and the ground conductor13is located on the second main surface103of the substrate101. The signal conductor11opposes each of the ground conductor12and the ground conductor13. The signal conductor11has a width smaller than a width of the ground conductor12and a width of the ground conductor13.

Accordingly, the high-frequency signal transmission line10defines a strip line and transmits a high-frequency signal in the direction where the substrate101extends.

The power supply line20is located near the side surface105of the substrate101. The power supply line20includes a main conductor21, a ground conductor22, and a ground conductor23. Each of the main conductor21, the ground conductor22, and the ground conductor23extends in the direction where the substrate101extends.

The main conductor21is located substantially at a center of the substrate101in the thickness direction of the substrate101. The ground conductor22is located on the first main surface102of the substrate101, and the ground conductor23is located on the second main surface103of the substrate101. The main conductor21opposes each of the ground conductor22and the ground conductor23. The main conductor21has a width smaller than a width of the ground conductor22and a width of the ground conductor23. However, the main conductor21preferably has a width that is relatively larger, in particular, a width closer to the width of the ground conductor22and the width of the ground conductor23, for example.

Accordingly, the power supply line20transmits a power signal (DC power signal) in the direction where the substrate101extends.

The differential signal transmission line30is located substantially at a center of the substrate101in the width direction of the substrate101. In other words, the differential signal transmission line30is located between the high-frequency signal transmission line10and the power supply line20.

The differential signal transmission line30includes a first signal conductor31, a second signal conductor32, a ground conductor33, and a ground conductor34. Each of the first signal conductor31, the second signal conductor32, the ground conductor33, and the ground conductor34extends in the direction where the substrate101extends.

The first signal conductor31is positioned closer to the first main surface102with respect to the center of the substrate101in the thickness direction of the substrate101. The second signal conductor32is positioned closer to the second main surface103with respect to the center of the substrate101in the thickness direction of the substrate101. In other words, the first signal conductor31and the second signal conductor32are provided in parallel or substantially in parallel to each other in the direction where the substrate101extends, at a predetermined distance from each other in the thickness direction of the substrate101.

The ground conductor33is located on the first main surface102of the substrate101, and the ground conductor34is located on the second main surface103of the substrate101. The first signal conductor31opposes the ground conductor33, and the second signal conductor32opposes the ground conductor34. The first signal conductor31has a width equal or substantially equal to a width of the second signal conductor32, and the width of each of the first signal conductor31and the second signal conductor32is smaller than a width of the ground conductor33and a width of the ground conductor34.

Accordingly, the differential signal transmission line30includes each of the first signal conductor31and the second signal conductor32as a differential transmission line to transmit a differential signal in the direction where the substrate101extends.

As has been described above, the transmission line100includes the high-frequency signal transmission line10, the power supply line20, and the differential signal transmission line30between the high-frequency signal transmission line10and the power supply line20.

Here, the high-frequency signal transmission line10and the power supply line20are spaced away from each other at a distance equal or substantially equal to a size of the differential signal transmission line30. Accordingly, a noise from the power supply line20, for example, a switching noise overlapping the power signal transmitted from the power supply line20, is less prone to propagate to the high-frequency signal transmission line10.

Note that, on the first main surface102, the ground conductor12, the ground conductor22, and the ground conductor33are located at a predetermined distance from each other in the Y-axis direction. Similarly, on the second main surface103, the ground conductor13, the ground conductor23, and the ground conductor34are located at a predetermined distance from each other in the Y-axis direction. Accordingly, coupling via the ground conductors above is less prone to occur.

Further, between the high-frequency signal transmission line10and the power supply line20, the differential signal transmission line30includes the first signal conductor31and the second signal conductor32. Accordingly, the noise from the power supply line20is significantly reduced or prevented within the differential signal transmission line30, and the noise is even less prone to propagate to the high-frequency signal transmission line10.

In this state, as has been described above, each of the first signal conductor31and the second signal conductor32defines and functions as the differential transmission line. Accordingly, the differential signal transmission line30is highly resistant to the noise from the power supply line20. In other words, even when the noise from the power supply line20propagates to the differential signal transmission line30, an influence on transmission of the differential signal is limited.

Accordingly, in the transmission line100, even when the high-frequency signal, the differential signal, and power signal are transmitted from the substrate101as a single substrate, a fault due to mutual interference between these signals is less prone to occur, and transmission characteristics for each of the signals is less prone to be degraded.

Further, the transmission line100, which transmits each of the high-frequency signal, the differential signal, and the power signal, may be thinly structured.

As shown inFIGS. 3A and 3B, the electronic device900includes the transmission line100, a housing901, a circuit board902, a circuit board903, and a battery904. The electronic device900may be, for example, a portable information communication terminal.

The transmission line100, the circuit board902, the circuit board903, and the battery904are accommodated in the housing901. The circuit board902and the circuit board903are spaced away from each other. The battery904is between the circuit board902and the circuit board903.

In addition, the transmission line100includes an external connection terminal (omitted inFIGS. 1 and 2) at each end E100of the transmission line100in a direction where the transmission line100extends. In this state, the external connection terminal is provided to each of the high-frequency signal transmission line10, the power supply line20, and the differential signal transmission line30. As shown inFIGS. 3A and 3B, the transmission line100connects the circuit board902and the circuit board903via the external connection terminal at each end E100.

As shown inFIG. 4, the circuit board902includes, for example, a main controller91and a power supply circuit92thereon. As shown inFIG. 4, the circuit board903includes, for example, an RF transmitter/receiver93thereon. The RF transmitter/receiver93is connected to an antenna930(not shown inFIGS. 3A and 3B).

Accordingly, each of the high-frequency signal, the differential signal, and the power signal is transmitted between the RF transmitter/receiver93and the main controller91or the power supply circuit92. Here, as shown inFIG. 4, the main controller91and the RF transmitter/receiver93are connected as a circuit via the high-frequency signal transmission line10and the differential signal transmission line30. Further, the power supply circuit92and the RF transmitter/receiver93are connected via the power supply line20.

In terms of structure, the circuit board902including the main controller91and the power supply circuit92may be connected to the circuit board903including the RF transmitter/receiver93, via the high-frequency signal transmission line10, the differential signal transmission line30, and the power supply line20. In other words, as has been described, the circuit board902and the circuit board903may be connected via the transmission line100.

With the transmission line100according to the present preferred embodiment, the high-frequency signal transmission line10, the differential signal transmission line30, and the power supply line20are collectively wired by the transmission line100as a single transmission line. Accordingly, wiring is able to be performed easily in the electronic device900.

Further, the transmission line100may be thinly structured, for example, to be curved in the direction perpendicular or substantially perpendicular to each of the first main surface102and the second main surface103. Thus, as shown inFIG. 3B, the transmission line100may have a curved section CV and may be thus provided along an outer shape of the battery904. Accordingly, the wiring is able to be performed more freely in the electronic device900.

In the transmission line100, the ground conductor12and the ground conductor13are not connected. However, the ground conductor12and the ground conductor13may be connected via a ground conductor (interlayer connection conductor) extending in a thickness direction of the transmission line100(see a structure of a second preferred embodiment of the present invention described below). Similarly, the ground conductor22and the ground conductor23may be connected via a ground conductor (interlayer connection conductor) extending in the thickness direction of the transmission line100, and the ground conductor33and the ground conductor34may be connected via a ground conductor (interlayer connection conductor) extending in the thickness direction of the transmission line100.

The transmission line100described above may be manufactured by, for example, a non-limiting example of a method as follows.FIG. 5is a cross-sectional exploded view showing the non-limiting example of the method of manufacturing the transmission line according to the first preferred embodiment of the present invention.

A plurality of insulating resin materials, which are an insulating resin material1011, an insulating resin material1012, an insulating resin material1013, an insulating resin material1014, and an insulating resin material1015, each having a predetermined thickness, are prepared.

As shown inFIG. 5, the ground conductor12, the ground conductor22, and the ground conductor33are located on one main surface of the insulating resin material1011. The first signal conductor31is located on one main surface of the insulating resin material1012. The signal conductor11and the main conductor21are located on one main surface of the insulating resin material1013. The second signal conductor32is located on one main surface of the insulating resin material1014. The ground conductor13, the ground conductor23, and the ground conductor34are located on the other main surface of the insulating resin material1015.

The plurality of insulating resin materials1011to1015, each including the corresponding conductor(s) thereon, are laminated. Then, a laminate, which the insulating resin materials1011to1015have been laminated, is heat pressed.

By the method described above, the transmission line100is easily provided.

Second Preferred Embodiment

FIG. 6is a cross-sectional view showing a transmission line100A according to a second preferred embodiment of the present invention. As shown inFIG. 6, unlike the transmission line100of the first preferred embodiment, the transmission line100A according to the second preferred embodiment includes a shared ground conductor on each of a first main surface102and a second main surface103, and additionally includes a ground conductor extending in a thickness direction of the transmission line100A. Other features and structures of the transmission line100A are the same as or similar to those of the transmission line100, and thus a detailed description thereof will be omitted as appropriate.

The transmission line100A includes a ground conductor12A, a ground conductor13A, an interlayer connection conductor511, an interlayer connection conductor521, an interlayer connection conductor531and an interlayer connection conductor541, an auxiliary conductor512, an auxiliary conductor522, an auxiliary conductor532, and an auxiliary conductor542.

The ground conductor12A is located on the first main surface102of a substrate101. The ground conductor13A is located on the second main surface103of the substrate101.

A high-frequency signal transmission line10A includes a signal conductor11, the ground conductor12A, and the ground conductor13A. A power supply line20A includes a main conductor21, the ground conductor12A, and the ground conductor13A. A differential signal transmission line30A includes a first signal conductor31, a second signal conductor32, the ground conductor12A, and the ground conductor13A.

The interlayer connection conductor511connects the ground conductor12A and the ground conductor13A via the auxiliary conductor512that is located at a middle position of the interlayer connection conductor511in a thickness direction of the substrate101. Accordingly, each of the interlayer connection conductor511and the auxiliary conductor512defines and functions as a ground conductor extending in the thickness direction.

The interlayer connection conductor511and the auxiliary conductor512are provided between a side surface104of the substrate101and the signal conductor11in a width direction of the substrate101. In other words, the interlayer connection conductor511and the auxiliary conductor512are provided at an end of the high-frequency signal transmission line10A near the side surface104.

The interlayer connection conductor521connects the ground conductor12A and the ground conductor13A via the auxiliary conductor522that is located at a middle position of the interlayer connection conductor521in the thickness direction of the substrate101. Accordingly, each of the interlayer connection conductor521and the auxiliary conductor522defines and functions as a ground conductor extending in the thickness direction.

The interlayer connection conductor521and the auxiliary conductor522are provided between the signal conductor11and the first signal conductor31or the second signal conductor32in the width direction of the substrate101. In other words, the interlayer connection conductor521and the auxiliary conductor522are provided at a boundary between the high-frequency signal transmission line10A and the differential signal transmission line30A in the width direction of the substrate101.

The interlayer connection conductor531connects the ground conductor12A and the ground conductor13A via the auxiliary conductor532that is located at a middle position of the interlayer connection conductor531in the thickness direction of the substrate101. Accordingly, each of the interlayer connection conductor531and the auxiliary conductor532defines and functions as a ground conductor extending in the thickness direction.

The interlayer connection conductor531and the auxiliary conductor532are provided between the main conductor21and the first signal conductor31or the second signal conductor32in the width direction of the substrate101. In other words, the interlayer connection conductor531and the auxiliary conductor532are provided at a boundary between the differential signal transmission line30A and the power supply line20A in the width direction of the substrate101.

The interlayer connection conductor541connects the ground conductor12A and the ground conductor13A via the auxiliary conductor542that is located at a middle position of the interlayer connection conductor541in the thickness direction of the substrate101. Accordingly, each of the interlayer connection conductor541and the auxiliary conductor542defines and functions as a ground conductor extending in the thickness direction.

The interlayer connection conductor541and the auxiliary conductor542are provided between a side surface105of the substrate101and the main conductor21in the width direction of the substrate101. In other words, the interlayer connection conductor541and the auxiliary conductor542are provided at an end of the power supply line20A near the side surface105.

As has been described, with the transmission line100A, the ground conductor extending in the thickness direction is provided at the boundary between the high-frequency signal transmission line10A and the differential signal transmission line30A, and at the boundary between the differential signal transmission line30A and the power supply line20A. Accordingly, a noise from the main conductor21of the power supply line20A is shielded by the ground conductors extending in the thickness direction. Accordingly, the noise is less prone to propagate to the high-frequency signal transmission line10A.

Further, in the second preferred embodiment, unlike the first preferred embodiment, the ground conductor12A is shared on the first main surface102, and the ground conductor13A is shared on the second main surface103. With these shared ground conductors, each having a planar shape and an increased ground area, undesirable radiation is less prone to be leaked to outside from each of the high-frequency signal transmission line10A, power supply line20A, and the differential signal transmission line30A in the transmission line100A.

Note that, even when the ground conductor extending in the thickness direction is provided at any one of the boundaries, i.e., the boundary between the high-frequency signal transmission line10A and the differential signal transmission line30A or the boundary between the differential signal transmission line30A and the power supply line20A, the noise is able to be shielded. However, when the ground conductor extending in the thickness direction is provided at each of the boundaries, the noise is able to be further shielded.

The ground conductor extending in the thickness direction may be provided on each of the side surface104(an outer wall surface of the laminate) near the high-frequency signal transmission line10A and the side surface105(an outer wall surface of the laminate) near the power supply line20A. Accordingly, the undesirable radiation, generated at each of the high-frequency signal transmission line10A, power supply line20A, and the differential signal transmission line30A in the transmission line100A, is less prone to be leaked to outside through the side surfaces of the substrate101in the transmission line100A.

Note that, the ground conductor extending in the thickness direction may not be provided on the side surface104near the high-frequency signal transmission line10A or the side surface105near the power supply line20A. Accordingly, an overall width of the transmission line100A is reduced, thus resulting in the transmission line100A in smaller size.

Third Preferred Embodiment

FIG. 7is a cross-sectional view showing a transmission line100B according to a third preferred embodiment of the present invention. As shown inFIG. 7, the transmission line100B according to the third preferred embodiment includes a differential signal transmission line30B and a power supply line20B that respectively have different structures from those of the differential signal transmission line30and the power supply line20in the transmission line100of the first preferred embodiment. Other features and structures of the transmission line100B are the same as or similar to those of the transmission line100, and thus a detailed description thereof will be omitted as appropriate.

As shown inFIG. 7, the transmission line100B includes the power supply line20B and the differential signal transmission line30B.

The power supply line20B includes a main conductor21B, a ground conductor22, and a ground conductor23. The main conductor21B includes a plurality of plate conductors211and a plurality of connection conductors212. The plurality of plate conductors211are aligned in a thickness direction of a substrate101. The plurality of connection conductors212connect the plurality of plate conductors211in the thickness direction. Accordingly, in the power supply line20B, the main conductor21B has a cross-sectional area (cross-sectional area through which a power supply current flows) increased. Accordingly, in the power supply line20B, a power transmission loss is reduced.

The differential signal transmission line30B includes a control signal transmission line30C and a data transmission line30D. The control signal transmission line30C includes a first signal conductor31C, a second signal conductor32C, a ground conductor33C, and a ground conductor34C. The first signal conductor31C and the second signal conductor32C are located substantially at a center of the substrate101in the thickness direction of the substrate101, and are spaced away from each other in a width direction of the substrate101. The data transmission line30D includes a first signal conductor31D, a second signal conductor32D, a ground conductor33D, and a ground conductor34D. The first signal conductor31D and the second signal conductor32D are located substantially at a center of the substrate101in the thickness direction of the substrate101, and are spaced away from each other in the width direction of the substrate101.

The data transmission line30D is located closer to a high-frequency signal transmission line10with respect to the control signal transmission line30C. In other words, the control signal transmission line30C is located closer to the power supply line20B with respect to the data transmission line30D.

The data transmission line30D transmits data, for example, binarized data. The data transmission line30D transmits the data at a clock frequency that is lower than a frequency of a high-frequency signal transmitted by the high-frequency signal transmission line10.

The control signal transmission line30C transmits a control signal for, for example, a switching element of an RF transmitter/receiver93. The control signal is transmitted at lower frequency than the clock frequency for the data.

Accordingly, in the transmission line100B, the high-frequency signal transmission line10is further spaced away from the power supply line20B. Thus, a noise from the power supply line20B is even less prone to propagate to the high-frequency signal transmission line10.

Further, the control signal transmission line30C is located closer to the power supply line20B with respect to the data transmission line30D. The control signal transmission line30C transmits the control signal at lower frequency that is relatively resistant to noise, and the data transmission line30D transmits the data at higher frequency, i.e., the clock frequency, that is relatively less resistant to noise. Thus, as exemplified by the differential signal transmission line30B, even when the transmission line100B includes the data transmission line30D, the noise from the power supply line20B is less prone to propagate to the data transmission line30D.

Accordingly, even when the transmission line100B further includes transmission lines to transmit various signals or data in the substrate101as a single substrate, transmission characteristics for each of the signals or data is less prone to be degraded. Further, the transmission line100B may be easily curved. Here, even when including the transmission lines to transmit various signals or data, the transmission line100B is structured more freely.

Fourth Preferred Embodiment

FIG. 8is a cross-sectional view showing a transmission line100C according to a fourth preferred embodiment of the present invention. As shown inFIG. 8, the transmission line100C according to the fourth preferred embodiment includes a high-frequency signal transmission line10, a differential signal transmission line30, and a power supply line20, each provided in a different direction from in the transmission line100according to the first preferred embodiment. Other features and structures of the transmission line100C are similar to those of the transmission line100, and thus a detailed description thereof will be omitted as appropriate.

In the transmission line100C, the high-frequency signal transmission line10, the differential signal transmission line30, and the power supply line20are sequentially aligned in a thickness direction of a substrate101C. More specifically, the substrate101C has a first main surface102and a second main surface103, and the high-frequency signal transmission line10, the differential signal transmission line30, and the power supply line20are sequentially provided from the first main surface102toward the second main surface103.

The high-frequency signal transmission line10includes a signal conductor11, a ground conductor12on the first main surface102, and a ground conductor13C. The signal conductor11is provided between the ground conductor12and the ground conductor13C.

The differential signal transmission line30includes a first signal conductor31, a second signal conductor32, the ground conductor13C, and a ground conductor14C. The ground conductor13C is shared with the high-frequency signal transmission line10. The first signal conductor31and the second signal conductor32are aligned in a width direction of the substrate101C. The first signal conductor31and the second signal conductor32are provided between the ground conductor13C and the ground conductor14C.

The power supply line20includes a main conductor21, the ground conductor14C, and a ground conductor15C on the second main surface103. The ground conductor14C is shared with the differential signal transmission line30. The main conductor21is provided between the ground conductor14C and the ground conductor15C.

Accordingly, similarly to each of the foregoing preferred embodiments, a noise from the power supply line20is less prone to propagate to the high-frequency signal transmission line10. Further, the transmission line100C may be reduced in width.

Note that, the thickness is emphasized inFIG. 8, but in the transmission line100C, the thickness may actually be smaller than the width. Accordingly, similarly to the transmission line in each of the foregoing preferred embodiments, the transmission line100C may be curved.

In the transmission line100C, the substrate101C further includes a first section1011C, a second section1012C, and a third section1013C. The high-frequency signal transmission line10is located in the first section1011C. The power supply line20is located in the second section1012C. The differential signal transmission line30is located in the third section1013C.

The first section1011C, the second section1012C, and the third section1013C are preferably made of different materials from each other. Here, “made of different materials from each other” includes a case where these sections are made of the same or similar main material, but a content ratio of each of other materials to the main material varies among these materials.

For example, the first section1011C is made of, for example, an insulating resin material, and the third section1013C is made of, for example, the insulating resin material to which a magnetic substance is added as a filler. Accordingly, a degree of coupling of the differential signal transmission line30is able to be significantly improved without affecting transmission characteristics of the high-frequency signal transmission line10.

Further, the second section1012C is made of, for example, a material greater in heat resistance and heat dissipation than the material of the first section1011C. Then, while the transmission characteristics of the high-frequency signal transmission line10is not affected, the power supply line20is significantly improved in heat resistance and heat dissipation, thus resulting in the transmission line100C having higher reliability.

As has been described, by selecting a material for each section of the substrate101, the characteristics and reliability of each of the high-frequency signal transmission line10, the differential signal transmission line30, and the power supply line20are able to be significantly improved.

Further, the plurality of insulating resin materials are laminated to provide the substrate101C, and the first section1011C, the second section1012C, and the third section1013C are easily structured.

Note that, in the description of the transmission line100C, the first section1011C, the second section1012C, and the third section1013C are made of different materials from each other. However, in accordance with predetermined characteristics of the transmission line100C, one of the sections described above may be made of a material different from those of the other two, while the other two share the same or similar material.

Note that, the features and structures described in each of the foregoing preferred embodiments may be combined while providing the advantageous effects in each combination.