Patent Publication Number: US-11031700-B2

Title: Antenna module and communication device

Description:
This is a continuation of International Application No. PCT/JP2018/012228 filed on Mar. 26, 2018 which claims priority from Japanese Patent Application No. 2017-076732 filed on Apr. 7, 2017. The contents of these applications are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to an antenna module and a communication device. 
     Description of the Related Art 
     An array antenna device for wireless communication that includes patch antennas that are arranged in an array on a front surface of an antenna substrate is disclosed (see, for example, Patent Document 1). In this structure, an alignment mark that represents the location or direction of a component that is mounted is formed on a back surface of the antenna substrate.
     Patent Document 1: International Publication No. 2016/067906   

     BRIEF SUMMARY OF THE DISCLOSURE 
     In some cases, an antenna module that includes an array antenna has identification marks such as a product identification number, a shipment inspection mark, and the alignment mark for recognizing the location or direction of a component that is mounted. 
     In the array antenna device disclosed in Patent Document 1, the alignment mark is formed on the back surface of the antenna substrate. After the array antenna device is mounted on, for example, a mother substrate, it is difficult to check the identification mark such as the alignment mark because the alignment mark is checked from the front of the front surface of the antenna substrate. Consequently, there is a problem in that the number of processes for checking the identification mark increases. 
     In some cases where the identification mark is formed at a location near the front surface of the antenna substrate, antenna characteristics are affected, although the number of processes for checking the identification mark decreases. In a method for forming the identification mark at the location near the front surface of the antenna substrate without affecting the antenna characteristics, an area in which the identification mark is to be formed is defined within an outer circumferential area around an area in which the patch antennas are formed. In this case, however, the size of the antenna module increases. In the case where the antenna module is used in a short wave length band such as a millimeter band, it is necessary to reduce a transmission loss in the antenna module and a transmission loss between the antenna module and an external circuit as much as possible. Also, from the perspective of the reduction in the transmission loss in the millimeter band, it is not preferable that a separated area in which the identification mark is to be formed is defined within the outer circumferential area around the area in which the patch antennas are formed and near the front surface of the antenna substrate, which leads to an increased size. 
     The present disclosure has been accomplished to solve the above problems, and it is an object of the present disclosure to provide a small antenna module and a communication device that inhibit the antenna characteristics from being degraded and that include an identification mark that can be readily sighted. 
     To achieve the above object, an antenna module according to an aspect of the present disclosure includes a dielectric substrate, patch antennas that are disposed at locations near a first main surface of the dielectric substrate, a radio frequency circuit component that is mounted at a location near a second main surface of the dielectric substrate opposite the first main surface and that is electrically connected to the patch antennas, and an identification mark that is located in an antenna arrangement area that is an area of the dielectric substrate near the first main surface of the dielectric substrate and except for an outer circumferential area in which the patch antennas are not arranged in a plan view of the first main surface. The identification mark is located in the antenna arrangement area so as not to overlap feed points with which the respective patch antennas are provided in a plan view of the first main surface. 
     This enables the identification mark to be sighted more easily than in the case where the identification mark is located at a location near a back surface of the dielectric substrate because the identification mark is located at a location near the front surface of the dielectric substrate, at which the patch antennas are formed. For this reason, lot information, for example, can be readily traced. The patch antennas and the radio frequency circuit component are arranged with the dielectric substrate interposed therebetween. The identification mark is not located near the feed points at which signal sensibility is high. There is no need for a separated area in which the identification mark is formed within the outer circumferential area around the antenna arrangement area. Accordingly, antenna characteristics of the antenna module are not degraded, and area reduction and size reduction can be achieved. In addition, radio frequency transmission lines between the patch antennas and the radio frequency circuit component can be shortened, and a transmission loss can be reduced particularly in a frequency band in which the transmission loss is large such as a millimeter band. 
     The identification mark may not overlap any of the patch antennas in the plan view. 
     This enables the antenna characteristics of the antenna module to be further inhibited from being degraded even when the identification mark is located in the antenna arrangement area. 
     The patch antennas may be arranged in a matrix. The patch antennas may include a first patch antenna and a second patch antenna that are adjacent to each other in a row direction in the plan view, and a third patch antenna and a fourth patch antenna that are adjacent to each other in the row direction. The first patch antenna and the third patch antenna may be adjacent to each other in a column direction intersecting with the row direction in the plan view. The second patch antenna and the fourth patch antenna may be adjacent to each other in the column direction in the plan view. The identification mark may be located between the first patch antenna and the fourth patch antenna and between the second patch antenna and the third patch antenna. 
     This enables the antenna characteristics of the antenna module to be further inhibited from being degraded, and the degree of freedom of the shape of the identification mark can be improved even when the identification mark is located in the antenna arrangement area. 
     The patch antennas may be arranged in a matrix. The patch antennas may include a first patch antenna and a second patch antenna that are adjacent to each other in a row direction in the plan view. The feed point of the first patch antenna may be unevenly distributed in a column direction intersecting with the row direction from a center of the first patch antenna in the plan view. The feed point of the second patch antenna may be unevenly distributed in the column direction from a center of the second patch antenna in the plan view. The identification mark may be located between the first patch antenna and the second patch antenna. 
     In this case, the direction of polarization of the antenna module coincides with the column direction, and an area between the first patch antenna and the second patch antenna does not overlap a polarization surface in the plan view and has low antenna sensibility. Consequently, the antenna characteristics of the antenna module can be effectively inhibited from being degraded even when the identification mark is located in the antenna arrangement area. 
     The patch antennas may be arranged in a matrix. The patch antennas may include a first patch antenna and a second patch antenna that are adjacent to each other in a row direction in the plan view. The feed point of the first patch antenna may be unevenly distributed in the row direction from a center of the first patch antenna in the plan view. The feed point of the second patch antenna may be unevenly distributed in the row direction from a center of the second patch antenna in the plan view. The identification mark may be located between the first patch antenna and the second patch antenna. 
     This enables the antenna characteristics of the antenna module to be further inhibited from being degraded even when the identification mark is located in the antenna arrangement area. 
     An area between the first patch antenna and the second patch antenna may include a first area nearer than the second patch antenna to the first patch antenna and a second area nearer than the first patch antenna to the second patch antenna. The identification mark may be located in the first area or the second area that is nearer than the other area to a center of gravity between the feed point of the first patch antenna and the feed point of the second patch antenna. 
     In this case, the identification mark is located in the area that is interposed between the first patch antenna and the second patch antenna in which the antenna sensibility decreases. Consequently, the antenna characteristics of the antenna module can be effectively inhibited from being degraded even when the identification mark is located in the antenna arrangement area. 
     The identification mark may be composed of a metal material. 
     The identification mark that is composed of a metal material has high conductivity, and electric field distribution that is formed by the patch antennas is likely to be affected when the identification mark is proximate to the patch antennas. However, the identification mark that is composed of a metal material can be formed by the same process as a process of forming the patch antennas, and the identification mark does not overlap the patch antennas. Consequently, a process of manufacturing the antenna module can be simplified, and the antenna characteristics can be inhibited from being degraded. 
     The patch antennas may include a first patch antenna and a second patch antenna that are adjacent to each other in a row direction in the plan view, and a third patch antenna and a fourth patch antenna that are adjacent to each other in the row direction. The first patch antenna and the third patch antenna may be adjacent to each other in a column direction intersecting with the row direction in the plan view. The second patch antenna and the fourth patch antenna may be adjacent to each other in the column direction in the plan view. The identification mark may be located so as to contain a center of gravity of a planar shape that connects the feed point of the first patch antenna, the feed point of the second patch antenna, the feed point of the third patch antenna, and the feed point of the fourth patch antenna to each other in the plan view. 
     This prevents the antenna characteristics of the antenna module from being degraded and enables area reduction and size reduction to be achieved even when the identification mark is so large that the identification mark overlaps the patch antennas because the identification mark is located so as to contain the center of gravity at which the antenna sensibility is low. 
     The identification mark may be composed of a dielectric material. 
     The identification mark that is composed of a dielectric material has low conductivity and is unlikely to affect the electric field distribution that is formed by the patch antennas even when the identification mark is proximate to the patch antennas. Consequently, the antenna characteristics can be inhibited from being degraded by using a dielectric material for the identification mark even when the identification mark is so large that the identification mark overlaps the patch antennas. 
     A shield wire may be disposed at a location near the first main surface between the patch antennas in the plan view and that extends in directions in which the patch antennas are arranged. The identification mark may not overlap the shield wire in the plan view. 
     In this case, the identification mark is not in contact with the shield wire even with the shield wire arranged between the patch antennas. Accordingly, isolation between the patch antennas is improved, the antenna characteristics of the antenna module are not degraded, and area reduction and size reduction can be achieved. 
     The patch antennas may include a first patch antenna and a second patch antenna that are adjacent to each other in a row direction in the plan view. The feed point of the first patch antenna may be unevenly distributed in the row direction with respect to a center of the first patch antenna. The feed point of the second patch antenna may be unevenly distributed in the row direction with respect to a center of the second patch antenna. The identification mark may be located between the first patch antenna and the second patch antenna and in an area between the first patch antenna and the shield wire or an area between the second patch antenna and the shield wire that is nearer than the other area to a center of gravity between the feed point of the first patch antenna and the feed point of the second patch antenna. 
     In this case, the identification mark is located in an area that is interposed between the first patch antenna and the second patch antenna in which the antenna sensibility decreases. Consequently, the antenna characteristics of the antenna module can be effectively inhibited from being degraded. 
     A communication device according to an aspect of the present disclosure includes the above antenna module and a BBIC (base band IC). The radio frequency circuit component is a RFIC that performs a signal process of a transmission system for outputting, to each patch antenna, a signal that is received from the BBIC and that is up-converted, or a signal process of a reception system for outputting, to the BBIC, a radio frequency signal that is received from each patch antenna and that is down-converted, or both. 
     The communication device that includes the above antenna module enables, for example, identification information to be readily traced after the antenna module is mounted, prevents the antenna characteristics from being degraded, and enables area reduction and size reduction to be achieved. 
     The present disclosure provides a small antenna module and a communication device that inhibit the antenna characteristics from being degraded and that have an identification mark that can be readily sighted. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1A  is a perspective view of the appearance of an antenna module according to an embodiment. 
         FIG. 1B  is an exploded perspective view of the antenna module according to the embodiment. 
         FIGS. 2A and 2B  illustrate a plan view and a sectional view of the antenna module according to the embodiment, respectively. 
         FIGS. 3A, 3B and 3C  illustrate a plan view and sectional views of a simulation model, respectively. 
         FIG. 4  illustrates the distribution of the antenna gain obtained by a simulation. 
         FIG. 5A  illustrates the location of an identification mark of an antenna module according to a first example. 
         FIG. 5B  illustrates the location of an identification mark of an antenna module according to a second example. 
         FIG. 5C  illustrates the location of an identification mark of an antenna module according to a third example. 
         FIG. 5D  illustrates the location of an identification mark of an antenna module according to a fourth example. 
         FIG. 6  illustrates the location of an identification mark of an antenna module according to a fifth example. 
         FIG. 7  illustrates the location of an identification mark of an antenna module according to a sixth example. 
         FIG. 8  is a block diagram illustrating a communication device that includes the antenna module according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     An embodiment of the present disclosure will hereinafter be described in detail with reference to the drawings. The embodiment described below is a comprehensive or specific example. In the following embodiment, numerical values, shapes, materials, components, and the arrangement and connection form of the components, for example, are described by way of example and do not limit the present disclosure. Among the components according to the embodiment below, components that are not recited in the independent claims are described as optional components. The size of each component illustrated in the drawings or the ratio of the size is not necessarily illustrated strictly. In the drawings, substantially the same components are designated by like reference characters, and a duplicated description is omitted or simplified in some cases. 
     EMBODIMENT 
     [1 Antenna Module] 
     [1.1 Structure] 
       FIG. 1A ,  FIG. 1B ,  FIG. 2A , and  FIG. 2B  illustrate the structure of an antenna module  10  according to an embodiment. Specifically,  FIG. 1A  is a perspective view of the appearance of the antenna module  10  according to the embodiment, and  FIG. 1B  is an exploded perspective view of the antenna module  10  according to the embodiment.  FIG. 1B  illustrates a state in which a dielectric substrate  110  and a sealing member  120  are isolated from each other.  FIGS. 2A and 2B  illustrate a plan view and a sectional view of the antenna module  10  according to the embodiment, respectively. More specifically,  FIG. 2A  illustrates the plan view in which the dielectric substrate  110  is seen through, and the antenna module  10  is viewed from the front of an upper surface (from a plus location on a Z-axis in the figure), and  FIG. 2B  illustrates the sectional view taken along line II-II in  FIG. 2A . 
     In the following description, the thickness direction of the antenna module  10  is referred to as a Z-axis direction, orthogonal directions that are perpendicular to the Z-axis direction are referred to as an X-axis direction and a Y-axis direction, and the plus location on the Z-axis means a location near the upper surface of the antenna module  10 . In practical application, however, the thickness direction of the antenna module  10  does not coincide with the vertical direction in some cases. Accordingly, the location near the upper surface of the antenna module  10  is not limited by the upward direction. According to the present embodiment, the antenna module  10  has a substantially rectangular, flat plate shape, and the X-axis direction and the Y-axis direction are parallel to two side surfaces of the antenna module  10  that are adjacent to each other. The shape of the antenna module  10  is not limited thereto and may be, for example, a substantially circular, flat plate shape. Furthermore, the shape is not limited to a flat plate shape and may be a shape in which a central portion has a thickness that differs from that of an edge portion. 
     A surface electrode (also referred to as a land or a pad), which is a terminal of a RFIC  30 , or a conductive joining material (for example, solder) that is connected to the surface electrode is exposed from the upper surface of the sealing member  120 . In  FIG. 1B , however, an illustration thereof is omitted. In  FIG. 2B , for simplicity, some components that are technically located on different sections are illustrated in the same figure, or an illustration of some components that are located on the same section is omitted. 
     As illustrated in  FIG. 1A , the antenna module  10  includes the dielectric substrate  110 , patch antennas  100 , the RFIC  30 , and an identification mark  50 . According to the present embodiment, the sealing member  120  is disposed on the lower surface of the dielectric substrate  110 . Components that are included in the antenna module  10  will be specifically described. 
     As illustrated in  FIG. 2B , the dielectric substrate  110  includes a substrate body  110   a  composed of a dielectric material and various conductors for forming, for example, the above patch antennas  100 . According to the present embodiment, as illustrated in  FIG. 1B  and in  FIG. 2A , the dielectric substrate  110  is a multilayer substrate that has a substantially rectangular, flat plate shape and that includes stacked dielectric layers. The dielectric substrate  110 , however, is not limited thereto, may have, for example, a substantially circular, flat plate shape, and may be a single-layer substrate. 
     The patch antennas  100  are arranged at locations near an upper surface (plus locations on the Z-axis), which is near a first main surface of the dielectric substrate  110 , and radiate or receive radio frequency signals. According to the present embodiment, eighteen patch antennas  100  that are arranged in two dimensions of 6×3 form an array antenna. 
     The number and arrangement of the patch antennas  100  that form the array antenna are not limited thereto. For example, the patch antennas  100  may be arranged in a single dimension. The patch antennas  100  may not be arranged linearly in a row direction or a column direction and may be arranged in, for example, a staggered form. 
     As illustrated in  FIGS. 2A and 2B , each patch antenna  100  includes a pattern conductor that is disposed on the main surface of the dielectric substrate  110  substantially parallel thereto and includes a feed point  115  on the lower surface of the pattern conductor. The patch antenna  100  radiates a radio frequency signal that is fed into a space or receives a radio frequency signal in the space. According to the present embodiment, the patch antenna  100  radiates a radio frequency signal that is fed from the RFIC  30  to the feed point  115  into the space or receives a radio frequency signal in the space to output the radio frequency signal from the feed point  115  to the RFIC  30 . That is, the patch antenna  100  according to the present embodiment also serves as a radiating element that radiates a radio wave (a radio frequency signal propagating through a space) corresponding to the radio frequency signal that is transmitted between the patch antenna  100  and the RFIC  30  and as a receiving element that receives the radio wave. 
     According to the present embodiment, each patch antenna  100  has a rectangular shape surrounded by a pair of sides that extend in the Y-axis direction and that are opposite to each other in the X-axis direction and a pair of sides that extend in the X-axis direction and that are opposite to each other in the Y-axis direction in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis), and the feed point  115  is located so as to shift from the center of the rectangular shape in a minus direction along a Y-axis. For this reason, the direction of polarization of the radio wave that is radiated or received by the patch antenna  100  according to the present embodiment coincides with the Y-axis direction. It is not necessary for each feed point  115  to be located at the same location in the corresponding patch antenna  100 . For example, the feed points  115  of some of the patch antennas  100  may be located so as to shift from the center in a plus direction along the Y-axis. In the case where the polarization does not have a single orientation but has plural orientations, the feed points  115  of some of the patch antennas  100  may be located so as to sit from the center in a direction along an X-axis. 
     The wave length and band width ratio of the radio wave, for example, depend on the size (the size in the Y-axis direction and the size in the X-axis direction, here) of each patch antenna  100 . For this reason, the size of the patch antenna  100  can be appropriately determined depending on a required specification such as a frequency. 
     In  FIG. 1A ,  FIG. 1B ,  FIG. 2A , and  FIG. 2B , for simplicity, the patch antennas  100  illustrated are exposed from the upper surface of the dielectric substrate  110 . However, it is only necessary for the patch antennas  100  to be disposed at locations near the upper surface of the dielectric substrate  110 . For example, when the dielectric substrate  110  is a multilayer substrate, the patch antennas  100  may be disposed in an inner layer of the multilayer substrate. 
     The location “near the upper surface” means a location above the center in the vertical direction. That is, regarding the dielectric substrate  110  that has the first main surface and a second main surface opposite thereto, “to be disposed at a location near the first main surface” means to be disposed at a location nearer than the second main surface to the first main surface. In the following description, the same is true for the expression of the other components. 
     As illustrated in  FIG. 1B ,  FIG. 2A  and  FIG. 2B , the antenna module  10  also includes signal conductor supports  123 , which are signal terminals, at locations near the lower surface of the dielectric substrate  110 . According to the present embodiment, the RFIC  30  and the signal conductor supports  123  are covered by the sealing member  120  except for the lower surface of the signal conductor supports  123 . The number of the signal conductor supports  123  is not particularly limited provided that the number is one or more. The signal conductor supports  123  may not be provided. That is, the dielectric substrate  110  with the patch antennas  100  formed may be directly mounted on a mother substrate (mounting substrate). 
     In addition to pattern conductors for forming the patch antennas  100 , the various conductors of the dielectric substrate  110  include a conductor for forming a circuit that is included in the antenna module  10  together with the array antenna and the RFIC  30 . Specifically, the conductors include via conductors  116  and a pattern conductor  117  included in feed lines for transmitting radio frequency signals between ANT terminals  121  of the RFIC  30  and the feed points  115  of the patch antennas  100 , and pattern conductors  119  for transmitting signals between the signal conductor supports  123  and I/O terminals  124  of the RFIC  30 . 
     The pattern conductor  117  is disposed in an inner layer of the dielectric substrate  110  along the main surface of the dielectric substrate  110  and connects, for example, the via conductor  116  that is connected to the feed point  115  of the patch antenna  100  and the via conductor  116  that is connected to the ANT terminal  121  of the RFIC  30  to each other. 
     Each via conductor  116  is an interlayer connection conductor that extends in the thickness direction perpendicular to the main surface of the dielectric substrate  110  and that connects, for example, pattern conductors that are disposed in different layers to each other. 
     The pattern conductors  119  are disposed on the lower surface of the dielectric substrate  110  along the main surface of the dielectric substrate  110  and connect, for example, the signal conductor supports  123  and the I/O terminals  124  of the RFIC  30  to each other. 
     Examples of the dielectric substrate  110  include a low temperature co-fired ceramic (LTCC) substrate or a printed circuit board. 
     In the dielectric substrate  110 , a pair of ground pattern conductors that are opposite to each other with the pattern conductor  117  interposed therebetween may be disposed in layers above and below the pattern conductor  117 . The ground pattern conductors may be disposed over the entire length of the dielectric substrate  110 . The pattern conductors  119  may be disposed in an inner layer of the dielectric substrate  110  and may connect the signal conductor supports  123  and the I/O terminals  124  of the RFIC  30  to each other with via conductors interposed therebetween. 
     The sealing member  120  is disposed at a location near the lower surface (second main surface) of the dielectric substrate  110  and composed of a resin that seals the RFIC  30 . According to the present embodiment, the RFIC  30  and the signal conductor supports  123  are embedded in the sealing member  120 . The material of the sealing member  120  is not particularly limited, and examples thereof include an epoxy resin or a polyimide resin. 
     The sealing member  120  may not be in direct contact with the lower surface of the dielectric substrate  110 , and an insulating film, for example, may be disposed between the sealing member  120  and the lower surface. 
     The RFIC  30  is a radio frequency circuit component that is mounted at a location near the lower surface of the dielectric substrate  110  and that is electrically connected to the patch antennas  100 , and forms a RF-signal-processing circuit. The RFIC  30  performs the signal process of the transmission system for outputting, to each patch antenna  100 , a signal that is received from a BBIC  40  described later via the corresponding signal conductor support  123  and that is up-converted, or the signal process of the reception system for outputting, to the BBIC  40 , a radio frequency signal that is received from the patch antenna  100  and that is down-converted via the signal conductor support  123 , or both. 
     According to the present embodiment, the RFIC  30  includes the ANT terminals  121  associated with the corresponding patch antennas  100  and the I/O terminals  124  associated with the corresponding signal conductor supports  123 . For example, the RFIC  30  performs the signal process of the transmission system for, for example, up-converting and demultiplexing a signal that is inputted into the I/O terminal  124  (that functions as an input terminal here) in the transmission system via the signal conductor support  123  in the transmission system to feed signals from the ANT terminals  121  to the patch antennas  100 . For example, the RFIC  30  performs the signal process of the reception system for, for example, multiplexing and down-converting signals that are received by the patch antennas  100  and that are inputted into the ANT terminals  121  to output a signal from the I/O terminal  124  (that functions as an output terminal) in the reception system via the signal conductor support  123  in the reception system. 
     An example of signal processing of the RFIC  30  will be described later together with the structure of a communication device that uses the antenna module  10 . 
     As illustrated in  FIGS. 2A and 2B , the RFIC  30  is preferably disposed in an area obtained by projecting, in the Z-axis direction, an antenna arrangement area, which is an upper surface area of the dielectric substrate  110  in which the patch antennas  100  are arranged, when viewed in the direction perpendicular to the upper surface of the dielectric substrate  110  (that is, from a plus location on the Z-axis). In this manner, the feed lines that connect the RFIC  30  and the patch antennas  100  to each other can be designed to be short. 
     The antenna arrangement area is the minimum area that contains the patch antennas  100  when viewed in the above direction and is a rectangular area according to the present embodiment. In other words, the antenna arrangement area is an area near the upper surface of the dielectric substrate  110  and except for an outer circumferential area in which the patch antennas  100  are not arranged. The shape of the antenna arrangement area corresponds to the form of arrangement of the patch antennas  100  and is not limited to a rectangular shape. 
     Each signal conductor support  123  is disposed at a location near the lower surface of the dielectric substrate  110 , is a signal terminal that is electrically connected to the RFIC  30 , and is a conductor support that extends through the sealing member  120  in the thickness direction. The upper surface of the signal conductor support  123  is connected to the corresponding pattern conductor  119  of the dielectric substrate  110 , and the lower surface thereof is exposed from the lower surface of the sealing member  120 . The signal conductor support  123  becomes an outer connection terminal of the antenna module  10  when the antenna module  10  is mounted on the mother substrate (not illustrated). That is, the antenna module  10  is mounted on the mother substrate in a manner in which the signal conductor support  123  is electrically and mechanically connected to an electrode of the mother substrate by, for example, reflow. The material of the signal conductor support  123  is not particularly limited, and an example thereof is a copper having a low resistance value. 
     Each signal conductor support  123  may not be disposed on the lower surface of the dielectric substrate  110 . That is, an upper end portion of the signal conductor support  123  may be embedded in the dielectric substrate  110  and may not be in direct contact with the lower surface of the dielectric substrate  110 , and an insulating film, for example, may be disposed between the signal conductor support  123  and the lower surface. 
     In the antenna module  10  according to the present embodiment, the patch antennas  100  are disposed at locations near the first main surface (near the upper surface according to the present embodiment) of the dielectric substrate  110 , and the radio frequency circuit component (the RFIC  30  according to the present embodiment) is mounted at a location near the second main surface (near the lower surface according to the present embodiment) of the dielectric substrate  110 , as described above. 
     According to the present embodiment, in this manner, the feed lines that connect the radio frequency circuit component and the patch antennas  100  to each other can be designed to be short. This enables a loss due to the feed lines to be reduced, and achieves high performance of the antenna module  10 . The antenna module  10  is suitable for a millimeter-band antenna module that is likely to increase the loss due to the feed lines as the length of the feed lines increases. 
     The antenna module  10  according to the present embodiment includes the identification mark  50 . The identification mark  50  is any one of a symbol, a character, a numeral, a figure, and a combination thereof, and examples thereof include a lot number that represents the product identification number of the antenna module  10 , a shipment inspection mark, and an alignment mark for recognizing the location and direction of a component that is mounted. That is, the identification mark  50  is a mark for identifying the antenna module  10  while the antenna module  10  is being manufactured and after the antenna module  10  is manufactured. 
     The identification mark  50  is composed of, for example, a metal material or a dielectric material. In case where the identification mark  50  is composed of a metal material, the identification mark  50  can be formed at the same time as the patch antennas  100  are formed during a process of forming the patch antennas  100  because the patch antennas  100  are composed of a metal material. For this reason, a process of manufacturing the antenna module  10  can be simplified. In the case where the identification mark  50  is composed of a dielectric material, the identification mark  50  is formed by a process that differs from the process of forming the patch antennas  100 . The identification mark  50  that is composed of a dielectric material has low conductivity, and is unlikely to affect the electric field distribution that is formed by the patch antennas  100  even when the identification mark  50  is proximate to the patch antennas  100 . From the perspective that antenna characteristics of the patch antennas  100  are unlikely to be affected, the dielectric constant of a dielectric material of which the identification mark  50  is composed is preferably decreased. 
     According to the present embodiment, the identification mark  50  is located in the antenna arrangement area and does not overlap the feed points  115  with which the respective patch antennas  100  are provided in a plan view of the dielectric substrate  110  from the front of the upper surface of the antenna module (when viewed from a plus location on the Z-axis). The antenna arrangement area is the minimum area that contains the patch antennas  100  in a plan view of the dielectric substrate  110  as described above. In other words, the antenna arrangement area is the area of the upper surface of the dielectric substrate  110  except for the outer circumferential area in which the patch antennas  100  are not arranged. 
     This enables the identification mark  50  to be sighted without any damages after mounting because the identification mark  50  is located in the antenna arrangement area that is exposed to an outer space even after the antenna module  10  is mounted on, for example, the mother substrate. Consequently, identification information such as lot information can be readily traced. The patch antennas  100  and the RFIC  30  are arranged with the dielectric substrate  110  interposed therebetween. The identification mark  50  is not located near the feed points  115  at which signal sensibility is high. There is no need for a separated area in which the identification mark  50  is formed other than the antenna arrangement area. Accordingly, the antenna characteristics of the antenna module  10  are not degraded, and area reduction and size reduction can be achieved. In addition, radio frequency transmission lines between the patch antennas  100  and the RFIC  30  can be shortened, and a transmission loss can be reduced particularly in a frequency band in which the transmission loss is large such as the millimeter band. 
     [1.2 Relationship Between Location of Identification Mark and Antenna Characteristics] 
     The relationship between the location of the identification mark  50  and the antenna characteristics will now be described. What will be first described is a result of simulation of an effect of the identification mark  50  on the antenna characteristics. 
       FIGS. 3A, 3B and 3C  illustrate a plan view and sectional views of a simulation model, respectively.  FIG. 4  illustrates the distribution of the antenna gain obtained by the simulation. 
     The simulation model of an array antenna as illustrated in  FIGS. 3A, 3B and 3C  is set to evaluate the effect of the identification mark  50  on the antenna characteristics. Table 1 illustrates parameters of the simulation model. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 4 × 3 Array 
               
               
                 Entire Area 
                 9.92 mm × 5.615 mm 
               
               
                   
               
             
            
               
                 Width Lp1 of Parasitic Element 100a 
                 0.70 mm 
               
               
                 Width Lp2 of Driven Element 100b 
                 0.76 mm 
               
               
                 Location Lf of Feed Point 115 
                 0.108 mm  
               
               
                 Diameter Dvg of GND Conductor Removal 
                  0.3 mm 
               
               
                 (for Feed Via Passage) 
               
               
                 Width Wg of Shield Wire 118 
                 0.08 mm 
               
               
                 Gap Gg1 of Shield Wire 118 in X-axis Direction 
                 2.46 mm 
               
               
                 Gap Gg2 of Shield Wire 118 in Y-axis Direction 
                 1.845 mm  
               
               
                 Thickness tp1 of Dielectric Substrate 110 (driven 
                 0.22 mm 
               
               
                 element - Upper Surface) 
               
               
                 Thickness tp2 of Dielectric Substrate 110 (driven 
                 0.14 mm 
               
               
                 element - Lower Surface) 
               
               
                   
               
            
           
         
       
     
     Each patch antenna  100  of the antenna module  10  according to the embodiment illustrated in  FIG. 1A  and  FIG. 1B  is described by way of example as being composed of the single pattern conductor that has the feed point  115 . In the present simulation model, however, as illustrated in  FIG. 3C , each patch antenna  100  includes a driven element  100   b , which is a pattern conductor that has the feed point  115 , and a parasitic element  100   a  that does not have the feed point  115 , that faces the upper surface of the driven element  100   b , and that is away from the driven element  100   b . As illustrated in  FIG. 3A , a shield wire  118  is arranged in a lattice pattern between the patch antennas  100  that are adjacent to each other. 
     Variation in the antenna gain is calculated in the case where a metal piece (copper piece of 0.5 mm square×0.01 mm thickness) is placed at a location near the upper surface (at a plus location on the Z-axis) of an antenna of the simulation model illustrated in  FIGS. 3A, 3B and 3C  and Table 1. The metal piece affects the antenna gain (magnetic field distribution) more than the other material pieces. Accordingly, the metal piece is a suitable material for evaluating the effect of a foreign substance on the patch antennas that are arranged in a matrix. 
     The above metal piece is moved 0.5 mm in the X-axis direction or in the Y-axis direction within an area S on the left-hand side in  FIG. 4 . At this time, only four patch antennas within the area S are switched on.  FIG. 4  illustrates, on the right-hand side, a result of distributions of the antenna gain that are obtained with the metal piece arranged at different coordinates (X, Y) and that are overlapped. The following knowledge is obtained from the result in  FIG. 4 . 
     (1) In the case where the metal piece is not arranged, substantial antenna gain is 9.37 dBi. 
     (2) The antenna gain is decreased by 1.8 dB or less near the feed point (Q1 in  FIG. 4 ). 
     (3) The antenna gain is decreased by 0.8 dB or less near a location opposite the feed point (Q2 in  FIG. 4 ). 
     (4) The antenna gain is decreased by 0.1 dB or less at a location (Q3 in  FIG. 4 ) between the patch antennas that are adjacent to each other in the X-axis direction. 
     (5) The antenna gain is decreased by 2 dB or more at a location on an edge (Q4 in  FIG. 4 ) of a dielectric substrate that is proximate to the feed point. 
     The decrease in the antenna gain due to the location of the identification mark  50  is preferably 0.1 dB or less. It is revealed from this that the optimum location of the identification mark  50  is (4) the location (Q3 in  FIG. 4 ) between the patch antennas that are adjacent to each other in the X-axis direction. 
     The following description includes the location of the identification mark  50  that is led from the result of the above simulation in each antenna module  10  according to a first example to a sixth example. 
     [1.3 Location of Identification Mark According to First Example] 
       FIG. 5A  illustrates the location of the identification mark  50  of the antenna module  10  according to the first example.  FIG. 5A  illustrates a modification to the location of the identification mark  50  in an enlargement area P illustrated in  FIGS. 2A and 2B . 
     As illustrated in  FIG. 5A , there are patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 A and  100 B correspond to a first patch antenna and a second patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 C and  100 D correspond to a third patch antenna and a fourth patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 A and  100 C are adjacent to each other in the X-axis direction (the column direction intersecting with the row direction). The patch antennas  100 B and  100 D are adjacent to each other in the X-axis direction (the column direction). 
     As illustrated in  FIG. 5A , the identification mark  50  (“AB123” in  FIG. 5A ) does not overlap any of the patch antennas  100  ( 100 A to  100 D) in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). 
     The identification mark  50  is located between the patch antenna  100 A and the patch antenna  100 D and between the patch antenna  100 B and the patch antenna  100 C (in an area A in  FIG. 5A ). That is, the identification mark  50  does not overlap the four patch antennas  100 A to  100 D that are arranged in a matrix and is located in an area that is surrounded by the four patch antennas  100 A to  100 D in the plan view. 
     With the above structure, the identification mark can be sighted with no damage after mounting because the identification mark  50  is located in the antenna arrangement area even after the antenna module  10  is mounted. Consequently, the lot information, for example, can be readily traced. The patch antennas  100  and the RFIC  30  are arranged with the dielectric substrate  110  interposed therebetween. The identification mark  50  is not located near the feed points  115  at which the signal sensibility is high. There is no need for a separated area in which the identification mark  50  is formed other than the antenna arrangement area. Accordingly, the antenna characteristics of the antenna module  10  are not degraded, and area reduction and size reduction can be achieved. In addition, the radio frequency transmission lines between the patch antennas  100  and the RFIC  30  can be shortened, and the transmission loss can be reduced particularly in a frequency band in which the transmission loss is large such as the millimeter band. 
     In the area A in which the identification mark  50  is located, the antenna gain is decreased less than in an area that is interposed between two patch antennas, and the antenna characteristics of the antenna module  10  can be further inhibited from being degraded. In addition, the above area A can be larger than the area that is interposed between the two patch antennas in the X-axis direction and the Y-axis direction, and the degree of freedom of the shape of the identification mark  50  is improved. 
     In the case where the identification mark  50  is composed of a metal material, there is a possibility that the electric field distribution that is formed by the patch antennas  100  is likely to be affected when the identification mark  50  is proximate to the patch antennas  100  because the identification mark  50  has high conductivity, and that the antenna gain is further decreased. According to the first example, however, the identification mark  50  does not overlap any of the patch antennas  100  in the plan view. Accordingly, the identification mark  50  according to the present example may be composed of a metal material. This enables the identification mark  50  to be formed by the same process as the process of forming the patch antennas  100  that are composed of a metal material. Consequently, the process of manufacturing the antenna module  10  can be simplified, and the antenna characteristics can be inhibited from being degraded. 
     [1.4 Location of Identification Mark According to Second Example] 
       FIG. 5B  illustrates the location of the identification mark  50  of the antenna module  10  according to the second example.  FIG. 5B  illustrates a modification to the location of the identification mark  50  in the enlargement area P illustrated in  FIGS. 2A and 2B . The antenna module  10  illustrated in  FIG. 5B  differs from the antenna module  10  according to the first example illustrated in  FIG. 5A  in the location of the identification mark  50  only. Different subject matters between the antenna module  10  according to the second example and the antenna module  10  according to the first example will be mainly described, and a description of the same subject matters as in the antenna module  10  according to the first example is omitted. 
     As illustrated in  FIG. 5B , there are the patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 B and  100 D correspond to the first patch antenna and the second patch antenna that are adjacent to each other in the X-axis direction (the column direction). The feed point  115  of each of the patch antennas  100 A,  100 B,  100 C, and  100 D is unevenly distributed in the minus direction along the Y-axis (the row direction intersecting with the column direction) from the center of the patch antenna  100  in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). 
     As illustrated in  FIG. 5B , the identification mark  50  (“AB123” in  FIG. 5B ) does not overlap any of the patch antennas  100  ( 100 A to  100 D) in the plan view. 
     The identification mark  50  is located between the patch antenna  100 B and the patch antenna  100 D (in an area B in  FIG. 5B ). That is, the identification mark  50  is located in an area that does not intersect with a polarization surface of the patch antennas  100 B and a polarization surface of the patch antenna  100 D in the plan view. 
     With the above structure, the direction of polarization of the antenna module  10  coincides with the Y-axis direction (the row direction), the above area B does not overlap the polarization surfaces of the patch antennas  100 A to  100 D in the plan view and has low antenna sensibility, and the decrease in the antenna gain is small. Consequently, the antenna characteristics of the antenna module  10  can be effectively inhibited from being degraded even when the identification mark  50  is located in the area B. 
     The identification mark  50  according to the second example does not overlap any of the patch antennas  100  in the plan view. Accordingly, the identification mark  50  according to the present example may be composed of a metal material. This enables the identification mark  50  to be formed by the same process as the process of forming the patch antennas  100  that are composed of a metal material. Consequently, the process of manufacturing the antenna module  10  can be simplified, and the antenna characteristics can be inhibited from being degraded. 
     [1.5 Location of Identification Mark According to Third Example] 
       FIG. 5C  illustrates the location of the identification mark  50  of the antenna module  10  according to the third example.  FIG. 5C  illustrates a modification to the location of the identification mark  50  in the enlargement area P illustrated in  FIGS. 2A and 2B . The antenna module  10  illustrated in  FIG. 5C  differs from the antenna module  10  according to the first example illustrated in  FIG. 5A  in the location of the identification mark  50  only. Different subject matters between the antenna module  10  according to the third example and the antenna module  10  according to the first example will be mainly described, and a description of the same subject matters as in the antenna module  10  according to the first example is omitted. 
     As illustrated in  FIG. 5C , there are the patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 C and  100 D correspond to the first patch antenna and the second patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The feed point  115  of each of the patch antennas  100 A,  100 B,  100 C, and  100 D is unevenly distributed in the minus direction along the Y-axis (the row direction) from the center of the patch antenna  100  in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). 
     As illustrated in  FIG. 5C , the identification mark  50  (“AB123” in  FIG. 5C ) does not overlap any of the patch antennas  100  ( 100 A to  100 D) in the plan view. 
     The identification mark  50  is located between the patch antenna  100 C and the patch antenna  100 D (in an area C in  FIG. 5C ). That is, the identification mark  50  is located in an area intersecting with the polarization surface of the patch antenna  100 C and the polarization surface of the patch antenna  100 D in the plan view. 
     With the above structure, the direction of polarization of the antenna module  10  coincides with the Y-axis direction (the row direction), and the above area C intersects with the polarization surfaces of the patch antennas  100 A to  100 D in the plan view. However, the antenna sensibility thereof is lower than those in the patch antennas  100 , and the decrease in the antenna gain is small. Consequently, the antenna characteristics of the antenna module  10  can be inhibited from being degraded even when the identification mark  50  is located in the area C. 
     The identification mark  50  according to the third example does not overlap any of the patch antennas  100  in the plan view. Accordingly, the identification mark  50  according to the present example may be composed of a metal material. This enables the identification mark  50  to be formed by the same process as the process of forming the patch antennas  100  that are composed of a metal material. Consequently, the process of manufacturing the antenna module  10  can be simplified, and the antenna characteristics can be inhibited from being degraded. 
     [1.6 Location of Identification Mark According to Fourth Example] 
       FIG. 5D  illustrates the location of the identification mark  50  of the antenna module  10  according to the fourth example.  FIG. 5D  illustrates a modification to the location of the identification mark  50  in the enlargement area P illustrated in  FIGS. 2A and 2B . The antenna module  10  illustrated in  FIG. 5D  differs from the antenna module  10  according to the first example illustrated in  FIG. 5A  in the location of the identification mark  50  only. Different subject matters between the antenna module  10  according to the fourth example and the antenna module  10  according to the first example will be mainly described, and a description of the same subject matters as in the antenna module  10  according to the first example is omitted. 
     As illustrated in  FIG. 5D , there are the patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 C and  100 D correspond to the first patch antenna and the second patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The feed point  115  of each of the patch antennas  100 A,  100 B,  100 C, and  100 D is unevenly distributed in the minus direction along the Y-axis (the row direction) from center of the patch antenna  100  in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). 
     As illustrated in  FIG. 5D , the identification mark  50  (“AB123” in  FIG. 5D ) does not overlap any of the patch antennas  100  ( 100 A to  100 D) in the plan view. 
     As illustrated in  FIG. 5D , an area between the patch antenna  100 C and the patch antenna  100 D contains an area C1 (first area) nearer than the patch antenna  100 D to the patch antenna  100 C and an area C2 (second area) nearer than the patch antenna  100 C to the patch antenna  100 D. 
     In the above structure, the identification mark  50  is located in the area C2 that is nearer than the area C1 to the center of gravity G1 between the feed point  115  of the patch antenna  100 D and the feed point  115  of the patch antenna  100 C. In other words, the identification mark  50  is located in the area C2 that is farther than the area C1 to the feed points  115  of the patch antennas  100 . 
     With the above structure, the identification mark  50  is located in the area that is interposed between the patch antenna  100 C and the patch antenna  100 D in which the antenna sensibility decreases. Consequently, the antenna characteristics of the antenna module can be effectively inhibited from being degraded even when the identification mark  50  is located in the area C2. 
     The identification mark  50  according to the fourth example does not overlap any of the patch antennas  100  in the plan view. Accordingly, the identification mark  50  according to the present example may be composed of a metal material. This enables the identification mark  50  to be formed by the same process as the process of forming the patch antennas  100  that are composed of a metal material. Consequently, the process of manufacturing the antenna module  10  can be simplified, and the antenna characteristics can be inhibited from being degraded. 
     [1.7 Location of Identification Mark According to Fifth Example] 
       FIG. 6  illustrates the location of the identification mark  50  of the antenna module  10  according to the fifth example.  FIG. 6  illustrates a modification to the location of the identification mark  50  in the enlargement area P illustrated in  FIGS. 2A and 2B . The antenna module  10  illustrated in  FIG. 6  differs from the antenna module  10  according to the first example illustrated in  FIG. 5A  in the location of the identification mark  50  only. Different subject matters between the antenna module  10  according to the fifth example and the antenna module  10  according to the first example will be mainly described, and a description of the same subject matters as in the antenna module  10  according to the first example is omitted. 
     As illustrated in  FIG. 6 , there are the patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 A and  100 B correspond to the first patch antenna and the second patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 C and  100 D correspond to the third patch antenna and the fourth patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 A and  100 C are adjacent to each other in the X-axis direction (the column direction intersecting with the row direction). The patch antennas  100 B and  100 D are adjacent to each other in the X-axis direction (the column direction). 
     As illustrated in  FIG. 6 , the identification mark  50  (“AB123CD456EF789” in  FIG. 6 ) overlaps at least one of the patch antennas  100 A to  100 D in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). 
     The identification mark  50  is located so as to contain the center of gravity G2 between the feed point  115  of the patch antenna  100 A, the feed point  115  of the patch antenna  100 B, the feed point  115  of the patch antenna  100 C, and the feed point  115  of the patch antenna  100 D. In other words, the identification mark  50  is located such that the distance to the feed point  115  of each patch antenna  100  is the maximum distance. 
     This prevents the antenna characteristics of the antenna module  10  from being degraded and enables area reduction and size reduction to be achieved even when the identification mark  50  is so large that the identification mark  50  overlaps the patch antennas  100  because the identification mark  50  is located so as to contain the center of gravity G2 at which the antenna sensibility is low. 
     The identification mark  50  according to the fifth example may be composed of a dielectric material. The identification mark that is composed of a dielectric material has low conductivity and is unlikely to affect the electric field distribution that is formed by the patch antennas  100  even when the identification mark  50  is proximate to the patch antennas  100 . Consequently, the antenna characteristics can be inhibited from being degraded by using a dielectric material for the identification mark  50  even when the identification mark is so large that the identification mark overlaps the patch antennas  100  as in the identification mark  50  according to the present example. From the perspective that the antenna characteristics of the patch antennas  100  are unlikely to be affected, the dielectric constant of a dielectric material of which the identification mark  50  is composed is preferably decreased. 
     [1.8 Location of Identification Mark According to Sixth Example] 
       FIG. 7  illustrates the location of the identification mark  50  of the antenna module  10  according to the sixth example.  FIG. 7  illustrates a modification to the location of the identification mark  50  in the enlargement area P illustrated in  FIGS. 2A and 2B . The antenna module  10  illustrated in  FIG. 7  differs from the antenna module  10  according to the first example illustrated in  FIG. 5A  in the location of the identification mark  50  and the structure of the upper surface of the dielectric substrate  110 . Different subject matters between the antenna module  10  according to the sixth example and the antenna module  10  according to the first example will be mainly described, and a description of the same subject matters as in the antenna module  10  according to the first example is omitted. 
     As illustrated in  FIG. 7 , there are the patch antennas  100 A,  100 B,  100 C, and  100 D in the enlargement area P. The patch antennas  100 A and  100 B correspond to the first patch antenna and the second patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 C and  100 D correspond to the third patch antenna and the fourth patch antenna that are adjacent to each other in the Y-axis direction (the row direction). The patch antennas  100 A and  100 C are adjacent to each other in the X-axis direction (the column direction intersecting with the row direction). The patch antennas  100 B and  100 D are adjacent to each other in the X-axis direction (the column direction). 
     The antenna module  10  further includes the shield wire  118  that is disposed at a location near the upper surface (at a plus location on the Z-axis), which is near the first main surface of the dielectric substrate  110 . The shield wire  118  is arranged in a lattice pattern between the patch antennas  100  and extends in the directions in which the patch antennas  100  are arranged in a plan view of the antenna module  10  (when viewed from a plus location on the Z-axis). The shield wire  118  particularly improves the isolation between the patch antennas  100  that are adjacent to each other. 
     As illustrated in  FIG. 7 , the identification mark  50  (“AB123” at at least one of three locations illustrated in  FIG. 7 ) is located in the antenna arrangement area so as not to overlap the feed points  115  with which the respective patch antennas  100  are provided in the plan view. The antenna arrangement area is the minimum area that contains the patch antennas  100  in a plan view of the dielectric substrate  110  as described above. In other words, the antenna arrangement area is the area of the upper surface of the dielectric substrate  110  except for the outer circumferential area in which the patch antennas  100  are not arranged. 
     In addition, the identification mark  50  does not overlap the shield wire  118  in the plan view. 
     With the above structure, since the identification mark  50  does not overlap the shield wire  118 , the isolation between the patch antennas  100  is improved, the antenna characteristics of the antenna module  10  are not degraded, and area reduction and size reduction can be achieved. 
     As illustrated in  FIG. 7 , the identification mark  50  according to the present example may be located, for example, in any one of areas B1, B2, and C2 that do not overlap the shield wire  118  and that are located between two patch antennas  100 . 
     According to the present example, the feed point  115  of each of the patch antennas  100 A to  100 D is unevenly distributed in the minus direction along the Y-axis with respect to the center of the patch antenna. 
     In this case, the identification mark  50  may be located, for example, in the area C2 between the patch antenna  100 C and the patch antenna  100 D, among the area C1 and the area C2. The area C1 is located between the patch antenna  100 C and the shield wire  118 . The area C2 is located between the patch antenna  100 D and the shield wire  118 . This is due to the fact that the area C2 is nearer than the area C1 to the center of gravity G3 between the feed point  115  of the patch antenna  100 D and the feed point  115  of the patch antenna  100 C. 
     In this case, the identification mark  50  is located in the area C2 in which the antenna sensibility decreases within the area that is interposed between the patch antenna  100 C and the patch antenna  100 D that are adjacent to each other. Consequently, the antenna characteristics of the antenna module  10  can be effectively inhibited from being degraded even when the identification mark  50  is located in the area C2. 
     [2 Communication Device] 
     The antenna module  10  according to the present embodiment is mounted on the mother substrate such as the printed circuit board with the lower surface being a mounting surface, and can be included in a communication device, for example, together with the BBIC  40  that is mounted on the mother substrate. 
     Regarding this, the antenna module  10  according to the present embodiment achieves high directivity by controlling the phase and signal intensity of the radio frequency signal that is radiated from each patch antenna  100 . The antenna module  10  can be used for a communication device that supports, for example, massive MIMO (Multiple Input Multiple Output), which is one of promising wireless transmission technologies of 5G (the fifth generation mobile communication system). 
     In view of this, such a communication device and the process of the RFIC  30  of the antenna module  10  will now be described. 
       FIG. 8  is a block diagram illustrating a communication device  1  that includes the antenna module  10  according to the embodiment. In  FIG. 8 , for simplicity, only circuit blocks associated with four patch antennas  100  of the patch antennas  100  of an array antenna  20  among circuit blocks of the RFIC  30  are illustrated, and an illustration of the other circuit blocks is omitted. The circuit blocks associated with the four patch antennas  100  will be described below, and a description of the other circuit blocks is omitted. 
     As illustrated in  FIG. 8 , the communication device  1  includes the antenna module  10  and the BBIC  40  that is included in a base-band-signal-processing circuit. 
     The antenna module  10  includes the array antenna  20  and the RFIC  30  as described above. 
     The RFIC  30  includes switches  31 A to  31 D,  33 A to  33 D, and  37 , power amplifiers  32 AT to  32 DT, low-noise amplifiers  32 AR to  32 DR, attenuators  34 A to  34 D, phase shifters  35 A to  35 D, a signal combiner/demultiplexer  36 , a mixer  38 , and an amplifier circuit  39 . 
     The switches  31 A to  31 D and  33 A to  33 D are switch circuits for switching between transmission and reception through signal paths. 
     A signal that is transmitted from the BBIC  40  to the RFIC  30  is amplified by the amplifier circuit  39  and up-converted by the mixer  38 . A radio frequency signal that is up-converted is demultiplexed by the signal combiner/demultiplexer  36  into four signals, which pass through four transmission paths and are fed to the different patch antennas  100 . At this time, the directivity of the array antenna  20  can be adjusted by separately adjusting phase shifts of the phase shifters  35 A to  35 D that are arranged on the signal paths. 
     The radio frequency signals that are received by the patch antennas  100  of the array antenna  20  pass through four different reception paths, are multiplexed by the signal combiner/demultiplexer  36 , down-converted by the mixer  38 , amplified by the amplifier circuit  39 , and transmitted to the BBIC  40 . 
     The RFIC  30  may not include any one of the switches  31 A to  31 D,  33 A to  33 D, and  37 , the power amplifiers  32 AT to  32 DT, the low-noise amplifiers  32 AR to  32 DR, the attenuators  34 A to  34 D, the phase shifters  35 A to  35 D, the signal combiner/demultiplexer  36 , the mixer  38 , and the amplifier circuit  39  described above. The RFIC  30  may include only the transmission paths or the reception paths. The communication device  1  according to the present embodiment can be used for a system that transmits and receives not only a radio frequency signal in a single frequency band (a band) but also radio frequency signals in frequency bands (multi-band). 
     The RFIC  30  thus includes the power amplifiers  32 AT to  32 DT that amplify the radio frequency signals. The patch antennas  100  radiate the signals that are amplified by the power amplifiers  32 AT to  32 DT. 
     Since the communication device  1  with the above structure includes the antenna module  10  according to the present embodiment, the identification mark  50  can be sighted with no damage even after the antenna module  10  is mounted on the mother substrate because the identification mark  50  is located in the antenna arrangement area after the mounting. Consequently, the lot information, for example, can be readily traced. The patch antennas  100  and the RFIC  30  are arranged with the dielectric substrate  110  interposed therebetween. The identification mark  50  is not located near the feed points  115  at which the signal sensibility is high. There is no need for a separated area in which the identification mark  50  is formed other than the antenna arrangement area. Accordingly, the antenna characteristics of the antenna module  10  are not degraded, and area reduction and size reduction of the communication device  1  can be achieved. In addition, the radio frequency transmission lines between the patch antennas  100  and the RFIC  30  can be shortened, and the transmission loss can be reduced particularly in a frequency band in which the transmission loss is large such as the millimeter band. 
     (Other Modifications) 
     The antenna modules according to the embodiment of the present disclosure and the examples thereof and the communication device are described above. The present disclosure, however, is not limited to the above embodiment and the examples thereof. The present disclosure includes another embodiment that is achieved by a combination of freely selected components according to the above embodiment, a modification that is obtained by modifying the above embodiment in various ways that can be conceived by a person skilled in the art without departing from the spirit of the present disclosure, and various devices that include the antenna modules and the communication device according to the present disclosure. 
     For example, in the above description, the RFIC  30  performs both of the signal process of the transmission system and the signal process of the reception system, but is not limited thereto. The RFIC  30  may perform only one of the processes. 
     In the above description, the RFIC  30  is taken as an example of the radio frequency circuit component. The radio frequency circuit component, however, is not limited thereto. For example, the radio frequency circuit component is a power amplifier that amplifies a radio frequency signal, and each patch antenna  100  may radiate a signal that is amplified by the power amplifier. Alternatively, for example, the radio frequency circuit component may be a phase-adjusting circuit that adjusts the phase of a radio frequency signal that is transmitted between each patch antenna  100  and the radio frequency circuit component. 
     In the above description, the antenna module  10  includes the sealing member  120 . The antenna module  10 , however, may not include the sealing member  120 . Signal terminals such as the signal conductor supports  123  and a ground terminal may be surface electrodes, which are pattern electrodes that are disposed at locations near the second main surface (for example, on the second main surface) of the dielectric substrate  110 . The antenna module  10  with such a structure can be mounted on, for example, a mother substrate that has a cavity structure by using the signal terminals and the ground terminal. 
     According to the above embodiment, the patch antennas are described as antenna elements by way of example. However, the antenna elements that are included in the antenna module may not be the patch antennas, but may be, for example, rigid antennas or dipole antennas. 
     The present disclosure can be widely applied to antenna elements that have a band pass filter function for communication devices such as millimeter band mobile communication systems and massive MIMO systems.
           1  communication device     10  antenna module     20  array antenna     30  RFIC     31 A,  31 B,  31 C,  31 D,  33 A,  33 B,  33 C,  33 D,  37  switch     32 AR,  32 BR,  32 CR,  32 DR low-noise amplifier     32 AT,  32 BT,  32 CT,  32 DT power amplifier     34 A,  34 B,  34 C,  34 D attenuator     35 A,  35 B,  35 C,  35 D phase shifter     36  signal combiner/demultiplexer     38  mixer     39  amplifier circuit     40  BBIC     50  identification mark     100 ,  100 A,  100 B,  100 C,  100 D patch antenna     100   a  parasitic element     100   b  driven element     110  dielectric substrate     110   a  substrate body     115  feed point     116  via conductor     117 ,  119  pattern conductor     118  shield wire     120  sealing member     121  ANT terminal     123  signal conductor support     124  I/O terminal