Vehicle radio equipment

Abstract

To provide a vehicle radio device capable of forming a wider communication range.SOLUTION: A vehicle radio device 100 includes an L-shaped antenna 4 having a board parallel portion 42 facing a circuit board 3, on an upper-side surface of the circuit board 3. A ground pattern 35 serving as a ground plane is formed on a lower-side surface of the circuit board 3 so as to avoid an area overlapping the board parallel portion 42. A portion overlapping the board parallel portion 42 of a bottom surface portion 11 of a case is made of resin and is set to transmit radio waves. This allows a distance from a rear conductor plate to the board parallel portion 42 for the board parallel portion 42 to be secured longer. As a result, radio waves are more likely to propagate in a direction along vehicle body metal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle wireless device for performing wireless communication with an external device such as a portable terminal carried by a user or another vehicle. [Background technology]

[0002] Patent document 1 discloses a system in which a portable device and a vehicle communicate wirelessly using radio waves such as 2.45 GHz, and a configuration is disclosed in which it is determined whether or not the portable device is present in the vehicle cabin based on the reception status of signals from the portable device at multiple on-board antennas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-172334 Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in Patent Document 1, the reception state (e.g., reception strength) of a signal from a mobile terminal carried by a user can be used to detect the user's approach to a vehicle and to estimate the user's relative position with respect to the vehicle. In consideration of such applications, it is preferable that the vehicular wireless device be configured to be able to communicate well with the mobile terminal when the user is near the vehicle, regardless of the user's position or direction.

[0005] However, high-frequency radio waves of 700 MHz or higher, such as radio waves in the 2.4 GHz band, tend to travel in a more directional direction than low-frequency (LF) radio waves of 300 kHz or lower, making it difficult for the radio waves to bend around the metal of a vehicle body.

[0006] For example, if a vehicle wireless device is attached to the interior side of a pillar, it is difficult for direct waves from the vehicle wireless device to be deflected outside the vehicle cabin. In particular, linearly polarized waves, in which the electric field vibration direction is parallel to the metal surface, tend to be easily reflected by the metal. For an antenna that transmits polarized waves in which the electric field vibration direction is parallel to the metal surface to which it is attached, the back side of the attachment point is likely to be outside the line of sight. Note that the line of sight here refers to the range within which direct waves can propagate, while the outside line of sight refers to the range within which direct waves cannot propagate. The line of sight also includes areas where waves propagate due to diffraction, or in other words, deflection.

[0007] Of course, even if the mobile terminal is outside the line-of-sight range of the vehicle wireless device, the vehicle wireless device can receive signals from the mobile terminal due to reflections from other structures. However, using reflected waves to estimate the position of the mobile terminal increases the possibility of erroneously estimating the distance and direction of the mobile terminal.

[0008] When the line-of-sight range of each vehicle wireless device is narrow, in order to accurately determine the position of the user (i.e., the portable device), it becomes necessary to increase the number of vehicle wireless devices installed so that they can cover areas outside the line-of-sight range. However, the more vehicle wireless devices installed, the higher the system cost. Therefore, vehicle wireless devices including antennas for high-frequency radio waves are required to have a configuration that allows radio waves to easily reach the backside of the metal parts of the vehicle body to which they are attached.

[0009] The present disclosure has been made based on the above-mentioned viewpoint, and one of its objectives is to provide a vehicle wireless device that can form a wider communication range. [Means for solving the problem]

[0010] The first vehicle radio device disclosed herein comprises: a circuit board (3) made of a dielectric material and having mounted thereon a circuit (32) for transmitting or receiving radio waves at a predetermined target frequency of 700 MHz or more; a parallel polarization antenna (4, 4x) that is an antenna for receiving radio waves and has a board parallel portion (42) that is a portion parallel to the circuit board, thereby being configured to be able to receive board parallel polarization, which is radio waves whose electric field vibration direction is parallel to the circuit board; and a case (1, 2) that houses the circuit board and the parallel polarization antenna, and is used by mounting the circuit board in a position facing a predetermined mounting surface of the vehicle, and a ground portion (35) that is a conductor plate that provides a ground potential for the circuit, formed in an area of ​​the circuit board that overlaps with the board parallel portion. The case has a marker (24) on the side surface thereof, which is a line indicating the position of the parallel portion of the board inside the case. At least the portion of the bottom surface of the case facing the parallel portion of the board is made of resin. The case is attached to the vehicle body in such a manner that the parallel portion of the board is spaced apart from the vehicle body by λ / 4 (λ is the wavelength of radio waves) or more. .

[0011] Generally, a conductor plate acts as a reflector, which is an object that reflects radio waves. The ground section is also a plate-shaped conductor, and therefore acts as a reflector. According to the above configuration, since there is no ground section that can act as a reflector in the area overlapping with the parallel board section, the influence of reflection from the ground section can be weakened compared to when the ground section is formed directly below the parallel board section. Furthermore, since there is no ground section formed directly below the parallel board section, the area in which radio waves radiated from the parallel board section can freely propagate is expanded in the area below the parallel board section. As a result, a wider communication range can be achieved.

[0012] The second vehicle radio device disclosed herein comprises a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted, a parallel polarization antenna (4, 4x) which is an antenna for receiving radio waves and has a board parallel portion (42) which is a portion parallel to the circuit board, thereby being configured to be able to receive board parallel polarization, which is radio waves whose vibration direction of the electric field is parallel to the circuit board, and a case (1, 2) which houses the circuit board and the parallel polarization antenna, and is used by mounting the circuit board in a position facing a predetermined mounting surface of the vehicle, the bottom portion of the case is made of metal, the board parallel portion is located at a position electrically λ / 4 or more (λ is the wavelength of the radio waves) above the bottom portion (11) of the case, and a conductor plate facing the board parallel portion is located in a region inside the case which overlaps with the board parallel portion and is within λ / 4 below the board parallel portion. The second board (35B) is a conductive plate that provides a ground potential and is formed on the underside or inside of the second board. The second board is disposed below the first board in a position facing the first board, where the distance between the board parallel part and the second board ground part is electrically λ / 4 or more. A third vehicle radio device disclosed herein includes a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves at a predetermined target frequency of 700 MHz or more is mounted, a parallel polarization antenna (4, 4x) which is an antenna for receiving radio waves and has a board parallel portion (42) which is a portion parallel to the circuit board, thereby being configured to be able to receive board parallel polarization, which is radio waves whose electric field vibration direction is parallel to the circuit board, and a case (1, 2) for accommodating the circuit board and the parallel polarization antenna, and is used by mounting the circuit board in a position facing a predetermined mounting surface of the vehicle. A vehicle wireless device, the bottom of the case is made of metal, the board parallel portion is positioned above the bottom (11) of the case electrically by λ / 4 or more (λ is the wavelength of radio waves), and within the area inside the case that overlaps with the board parallel portion, in an area within λ / 4 below the board parallel portion, no conductor plate facing the board parallel portion is positioned, the circuit board includes a ground layer on which is formed a ground portion (35) that is a conductor plate that provides a ground potential for the circuit, and the board parallel portion is positioned relative to the circuit board so that the distance between the ground layer and the board parallel portion is electrically by λ / 4 or more. A fourth vehicle radio device disclosed herein includes a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves at a predetermined target frequency of 700 MHz or more is mounted, a parallel polarization antenna (4, 4x) which is an antenna for receiving radio waves and has a board parallel portion (42) which is a portion parallel to the circuit board, thereby being configured to be able to receive board parallel polarization, which is radio waves whose electric field vibration direction is parallel to the circuit board, and a case (1, 2) for accommodating the circuit board and the parallel polarization antenna, and the circuit board is mounted on a predetermined target frequency of the vehicle. This is a vehicle radio device that is mounted and used in a position facing the mounting surface, the bottom of the case is made of metal, the board parallel part is positioned electrically at least λ / 4 (λ is the wavelength of radio waves) above the bottom of the case (11), and within the area inside the case that overlaps with the board parallel part, in the area within λ / 4 below the board parallel part, no conductor plate facing the board parallel part is positioned, and the antenna has a three-dimensional shape with a standing part (41) that stands up from the circuit board and the board parallel part connected at the upper end of the standing part. A fifth vehicle radio device disclosed herein includes a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted, a parallel polarization antenna (4, 4x) which is an antenna for receiving radio waves and has a board parallel portion (42) which is a portion parallel to the circuit board, and is configured to be able to receive board parallel polarization, which is radio waves whose vibration direction of the electric field is parallel to the circuit board, and a case (1, 2) for accommodating the circuit board and the parallel polarization antenna, and the circuit board is mounted in a predetermined installation position of the vehicle. This is a vehicle wireless device that is mounted and used in a position facing the mounting surface, the bottom of the case is made of metal, the board parallel part is positioned above the bottom of the case (11) electrically by λ / 4 (λ is the wavelength of the radio wave), and within the area inside the case that overlaps with the board parallel part and that is within λ / 4 below the board parallel part, no conductor plate facing the board parallel part is positioned, and the board parallel part is formed on the surface or inside of a resin support part (34) that has a predetermined thickness and is positioned on the upper side of the circuit board. A sixth vehicle radio device disclosed herein includes a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted, a parallel polarization antenna (4, 4x) which is an antenna for receiving radio waves and has a board parallel portion (42) which is a portion parallel to the circuit board, thereby being configured to be able to receive board parallel polarization, which is radio waves whose vibration direction of the electric field is parallel to the circuit board, and a case (1, 2) for accommodating the circuit board and the parallel polarization antenna, and the circuit board is mounted on a predetermined mounting surface of the vehicle. The vehicle radio device is mounted and used in an opposing position to the circuit board, the bottom of the case is made of metal, the board parallel part is positioned electrically λ / 4 or more (λ is the wavelength of radio waves) above the bottom of the case (11), and within the area inside the case that overlaps with the board parallel part and that is within λ / 4 below the board parallel part, no conductor plate facing the board parallel part is positioned, and in addition to the parallel polarized wave antenna, it is equipped with a vertically polarized wave antenna (5) that can receive board vertically polarized waves, which are radio waves whose electric field vibration direction is perpendicular to the circuit board.

[0013] With this configuration, there is no conductive plate that can act as a reflector within λ / 4 below the parallel board portion. Therefore, radio waves emitted from the parallel board portion can propagate in various directions through the area below the parallel board portion. As a result, a wider communication area can be formed.

[0014] Note that the symbols in parentheses in the claims indicate a correspondence with the specific means described in the embodiments described below as one aspect, and do not limit the technical scope of the present disclosure. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is an exploded perspective view of the vehicle wireless device. [Figure 2] FIG. 2 is a diagram showing an example of an arrangement of various components on a circuit board. [Figure 3]FIG. 10 is a diagram for explaining an example of a method for realizing a three-dimensional antenna. [Figure 4] FIG. 10 is a diagram showing an example of a formation mode of a ground pattern. [Figure 5] 10A and 10B are conceptual diagrams for explaining the radiation direction and polarization plane of radio waves from the substrate parallel portion. [Figure 6] FIG. 10 is a diagram showing the simulation results of propagation strength when a dipole antenna is placed 9 mm away from the C-pillar in an orientation along the vehicle height direction. [Figure 7] FIG. 10 is a diagram showing the simulation results of propagation strength when a dipole antenna is placed at a position 60 mm away from the C-pillar in an orientation along the vehicle height direction. [Figure 8] FIG. 10 is a diagram for explaining the effect of the embodiment. [Figure 9] 10A and 10B are diagrams illustrating a modified example of the vehicle wireless device. [Figure 10] 10A and 10B are diagrams illustrating a modified example of the vehicle wireless device. [Figure 11] 10A and 10B are diagrams illustrating a modified example of the vehicle wireless device. [Figure 12] 10A and 10B are diagrams illustrating a modified example of the vehicle wireless device. [Figure 13] 10A and 10B are diagrams for explaining modified examples of antennas capable of receiving substrate-parallel polarized waves. [Figure 14] 10A and 10B are diagrams for explaining modified examples of antennas capable of receiving substrate-parallel polarized waves. [Figure 15] 10A and 10B are diagrams for explaining modified examples of antennas capable of receiving substrate-parallel polarized waves. [Figure 16] 10A and 10B are diagrams for explaining modified examples of the formation mode of the ground pattern. [Figure 17] 10 is a diagram showing an example of the configuration of a circuit board when the vehicle radio is equipped with a vertically polarized antenna; FIG. [Figure 18] FIG. 18 is a conceptual diagram showing a cross section taken along line XVIII-XVIII shown in FIG. 17. [Figure 19] 10A and 10B are diagrams illustrating modified examples of the configuration of the circuit board when the vehicle radio is equipped with a vertically polarized antenna. [Figure 20] 10A and 10B are diagrams showing modified examples of the configuration of the bottom surface portion 11. [Figure 21] FIG. 10 is a diagram showing an example of a configuration including a plurality of antennas 4. [Figure 22] FIG. 10 is a diagram showing another example of a configuration including a plurality of antennas 4. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Hereinafter, components having the same functions will be denoted by the same reference numerals, and their description will be omitted. Furthermore, when only a portion of the configuration is mentioned, the configuration of the previously described embodiment can be applied to the other portions.

[0017] It should be noted that "parallel" in this disclosure is not limited to a completely parallel state. It may be tilted by several degrees to approximately 15 degrees. In other words, it can include a state in which it is roughly parallel (a so-called substantially parallel state). The expression "perpendicular" in this disclosure is also not limited to a completely perpendicular state, but also includes a state in which it is tilted by several degrees to approximately 15 degrees. In this disclosure, "opposed" refers to a state in which two components face each other with a predetermined distance between them. The opposed state also includes a state in which two components face each other roughly, such as a state in which two components face each other at an angle of approximately 15 degrees.

[0018] <Example of use> The vehicular radio device 100 is a device for performing wireless communication with a communication device (hereinafter referred to as a mobile terminal) carried by a vehicle user. An example of a mobile terminal is a smartphone. The vehicular radio device 100 is connected to a smart ECU (not shown) when in use. The vehicular radio device 100 reports the reception status of a wireless signal from the mobile terminal to the smart ECU, for example, as information indicating the location of the mobile terminal. The reception status may include reception strength, signal round-trip flight time, phase difference, etc. The ECU in the component name is an abbreviation for Electronic Control Unit and refers to an electronic control device.

[0019] The vehicle radio device 100 may be disposed at multiple locations in the vehicle. For example, the vehicle radio device 100 may be disposed on the outer door handle of the driver's seat, the outer door handle of the passenger's seat, the inner surface of the left C-pillar, and the inner surface of the right C-pillar. As described above, each vehicle radio device 100 outputs a signal indicating the reception condition, such as reception strength, to the smart ECU as an indicator of the location of the mobile terminal.

[0020] The smart ECU is an ECU that realizes a passive entry and passive start system (hereinafter referred to as a PEPS system) by wirelessly communicating with a mobile terminal via the vehicle wireless device 100. The PEPS system is a system that performs vehicle control according to the location of the mobile terminal. The smart ECU determines the location of the mobile terminal relative to the vehicle based on, for example, the reception strength of signals from the mobile terminals input from multiple vehicle wireless devices 100 installed in the vehicle. The smart ECU then performs control such as locking or unlocking the doors on the condition that it has confirmed, through wireless communication with the mobile terminal, that the mobile terminal is near the vehicle door. Furthermore, when it has confirmed, through wireless communication with the mobile terminal, that the mobile terminal is inside the vehicle, it starts the driving source based on user operation of a start button (not shown). The PEPS system corresponds to a vehicle electronic key system such as a keyless entry system or a smart entry system.

[0021] <Overall configuration overview> FIG. 1 is a diagram showing an example of a schematic configuration of a vehicle radio device 100 according to the present disclosure. As shown in FIG. 1, the vehicle radio device 100 includes a lower case 1, an upper case 2, a circuit board 3, and an antenna 4. The upper case 2 is combined with the lower case 1 to form a flat rectangular parallelepiped case (in other words, a housing) whose thickness direction is perpendicular to the circuit board 3. That is, the vehicle radio device 100 has a flat rectangular parallelepiped outer shape as a whole. The circuit board 3 is also formed in a substantially rectangular shape corresponding to this shape. The antenna 4 is provided on the circuit board 3, for example.

[0022] The vehicular radio apparatus 100 is mounted to a predetermined position on the vehicle body when in use. For example, the vehicular radio apparatus 100 is mounted on the interior surface of a metal part of the vehicle body that is close to a window 210, such as a B-pillar or a C-pillar. Here, the pillar refers to a pillar that supports the roof, and the B-pillar refers to the second pillar from the front, and the C-pillar refers to the third pillar from the front. The vehicular radio apparatus 100 may be mounted on either the interior surface or the exterior surface of the metal part of the vehicle body. The vehicular radio apparatus 100 is mounted, for example, within 10 cm of the window frame of a side window for the rear seats, with a circuit board parallel portion (described later) parallel to the nearest window frame.

[0023] In another embodiment, the vehicular radio device 100 may be configured on the assumption that it will be disposed near a bumper, a door handle, a roof, a back / side mirror, a trunk door handle, or the like. The vehicular radio device 100 is attached so that a part or the entirety of the circuit board 3 faces an attachment target 200, which is a metal part of the vehicle body corresponding to the attachment destination. The attachment target 200 is determined in advance based on, for example, a request from a vehicle manufacturer. The attachment posture of the vehicular radio device 100 on the attachment target 200 is also set in advance. The surface of the metal part serving as the attachment target 200 corresponds to the attachment surface.

[0024] Hereinafter, the direction perpendicular to the circuit board 3 will be referred to as the up-down direction. The direction from the circuit board 3 toward the lower case 1 corresponds to the downward direction for the vehicle radio device 100, and the direction from the circuit board 3 toward the upper case 2 corresponds to the upward direction. The upward direction corresponds to the direction from the lower side surface, which is the surface facing the attachment target portion 200, to the upper side surface, which is the opposite surface, of the two surfaces of the circuit board 3.

[0025] Furthermore, the configuration of the vehicle radio device 100 will be described below by introducing the concept of a right-handed three-dimensional coordinate system having mutually orthogonal X-, Y-, and Z-axes. The X-axis shown in various drawings such as Fig. 1 represents the longitudinal direction of the circuit board 3, the Y-axis represents the lateral direction of the circuit board 3, and the Z-axis represents the up-down direction. Alternatively, if the circuit board 3 is square, the direction along any one of its sides can be set as the X-axis.

[0026] The three-dimensional coordinate system having the X-axis, Y-axis, and Z-axis is a concept for explaining the configuration of the vehicle radio device 100. When the vehicle radio device 100 is attached to a side surface of the vehicle interior such as a C-pillar, the X-axis corresponds to the longitudinal direction of the vehicle, the Y-axis corresponds to the vertical direction of the vehicle, and the Z-axis corresponds to the width direction of the vehicle. The positive direction of the Z-axis, i.e., the upper side of the vehicle radio device 100, can correspond to the direction from the attachment portion 200 toward the interior of the vehicle interior.

[0027] <Explanation of each component> The circuit board 3 is a substantially rectangular plate-like member formed by mounting various electronic components on a printed circuit board. The printed circuit board may be a multilayer board in which a plurality of conductor layers are built up on an insulating layer such as a glass epoxy board (in other words, FR4: Flame Retardant Type 4). Here, as an example, the circuit board 3 is realized using a glass epoxy resin with a relative dielectric constant of approximately 4.3 to 4.9. The circuit board 3 is a single-sided board or a double-sided board that does not include an internal conductor layer. Note that the circuit board 3 may also be realized using a multilayer board that includes an internal conductor layer, for example.

[0028] Screw holes 33 are formed in the four corners of the circuit board 3 for screwing the circuit board 3 to the lower case 1 and the upper case 2. The positions of the screw holes 33 can be changed as appropriate, as long as they are formed in corresponding positions on the lower case 1, the upper case 2, and the circuit board 3. Corresponding positions correspond to overlapping positions in a top view. The screw holes 33, in other words, the fixing portions for fixing the circuit board 3 to the lower case 1 and the upper case 2, may be provided in four or more locations. In addition to screws, various locking structures such as snap fits can be used to maintain the lower case 1, the upper case 2, and the circuit board 3 in an assembled state.

[0029] 2, an antenna 4, a connector 31, and a control circuit 32 are formed on the upper surface of the circuit board 3. The connector 31 is a component for connecting various cables such as a power cable and a communication cable with the smart ECU. The connector 31 is attached to the end of the circuit board 3 on the negative side of the Y axis, for example.

[0030] The control circuit 32 is a circuit module that controls the operation of the vehicular wireless device 100 and includes electronic components such as ICs. For example, the control circuit 32 includes a transmission / reception circuit and a power supply circuit. The transmission / reception circuit is a circuit module that performs signal processing related to at least one of signal transmission and signal reception. The transmission / reception circuit performs at least one of modulation, demodulation, frequency conversion, amplification, digital-to-analog conversion, and detection. The power supply circuit is a circuit module that converts voltage input from a power cable into a predetermined voltage suitable for the operation of the transmission / reception circuit and outputs the converted voltage.

[0031] The antenna 4 is an antenna for transmitting and receiving radio waves in a frequency band used in short-range wireless communication, such as Bluetooth Low Energy (Bluetooth is a registered trademark) and Wi-Fi (registered trademark). For example, the antenna 4 is configured to be able to transmit and receive radio waves in a frequency band from 2400 MHz to 2500 MHz (hereinafter referred to as the 2.4 GHz band). The target frequency, which is the operating frequency of the antenna 4, is an example and is not limited to the 2.4 GHz band. The target frequency band may be any of the 700 MHz band, 800 MHz band, 900 MHz band, 1.5 GHz band, 1.7 GHz band, 2 GHz band, 2.5 GHz band, 3.4 GHz band, 3.7 GHz band, 4.5 GHz band, 5 GHz, and 28 GHz band.

[0032] The antenna 4 is configured to transmit and receive radio waves of a predetermined target frequency. Of course, in other embodiments, the vehicle radio device 100 may be used for only either transmission or reception. That is, the antenna 4 may be a dual-purpose antenna for transmission and reception, or a dedicated antenna for reception. In this disclosure, the expression "antenna for transmitting and receiving radio signals of a certain frequency band" can include not only an antenna used for both transmission and reception, but also an antenna used only for reception. That is, the expression "transmitting and receiving" can be interpreted as meaning at least one of transmission, reception, or reception. The same applies to descriptions of transmitter / receiver circuits, etc. Because the operation of an antenna is reversible between transmitting and receiving radio waves, an antenna capable of receiving a certain radio wave can also be interpreted as an antenna capable of transmitting that radio wave.

[0033] In addition, the use of antenna 4 is not limited to short-range communication. Antenna 4 may be an antenna for transmitting and receiving radio waves (in other words, wireless signals) in the frequency band used in cellular communication. In other words, it may be an antenna for performing data communication with wireless base stations that constitute 4G or 5G mobile communication systems.

[0034] Hereinafter, "λ" represents the wavelength of radio waves of the target frequency (hereinafter also referred to as the target wavelength). For example, "λ / 2" and "0.5λ" refer to half the target wavelength, while "λ / 4" and "0.25λ" refer to one-quarter of the target wavelength. The wavelength (i.e., λ) of 2.4 GHz radio waves in a vacuum and in air is 125 mm. In the examples of dimensions of components constituting the vehicular wireless device 100, expressions using λ can be interpreted as the electrical length. Here, the electrical length refers to the effective length taking into account factors such as fringing electric fields and the wavelength-shortening effect of dielectrics. The electrical length is sometimes referred to as the effective length. Of course, for portions not affected by the wavelength-shortening effect, λ can be interpreted as the length in a vacuum or in air. For example, if the circuit board 3 is formed using a dielectric with a relative permittivity of 4.3, the λ within the circuit board 3 is theoretically approximately 60 mm due to the wavelength-shortening effect of the dielectric. Therefore, a dielectric plate with a relative dielectric constant of 4.3 and a thickness of 15 mm is electrically equivalent to a member having a thickness of λ / 4.

[0035] The antenna 4 is configured as a three-dimensional inverted-L antenna that stands upright on the surface of the circuit board, for example. In other words, the antenna 4 has a three-dimensional shape. Specifically, the antenna 4 includes an upright portion 41 that stands upright from the circuit board 3 and a board parallel portion 42 that is parallel to the surface of the circuit board 3. The upright portion 41 and the board parallel portion 42 are both predetermined linear conductors, and the upper end of the upright portion 41 is connected to one end of the board parallel portion 42. The expression "linear" also includes shapes that have a certain width / thickness. For example, the linear shape also includes a strip or rod shape whose width or thickness is sufficiently small compared to its longitudinal length.

[0036] The other end (lower end) of the standing portion 41 is electrically connected to a signal terminal of the transmitting / receiving circuit. That is, a feed point is formed at the lower end of the standing portion 41. The feed point is a portion where the signal terminal of the transmitting / receiving circuit and the antenna 4 as a radiating element are electrically connected via a wiring pattern including, for example, a microstrip line. The feed point can be understood as a connection point with the transmitting / receiving circuit or a feeder line.

[0037] The orientation of antenna 4 relative to the surface of the board can be maintained using, for example, solder, a connector, etc. Antenna 4 may be configured so that its orientation relative to circuit board 3 is maintained by inserting a pin-shaped insertion portion provided at the lower end of upright portion 41 into a through-hole formed in circuit board 3.

[0038] The antenna 4 has a configuration equivalent to a λ / 4 monopole bent at a right angle. The inverted-L antenna serving as the antenna 4 is realized by bending a linear (strip-shaped) metal sheet. As shown in FIG. 3, the inverted-L antenna serving as the antenna 4 may be patterned on the surface of a rectangular parallelepiped or plate-shaped support portion 34 made of a dielectric material having a dielectric constant equal to or greater than a predetermined value. The support portion 34 may be integrally formed with the circuit board 3. Such a support portion 34 may also be referred to as a stepped portion. The support portion 34 may also be a separately manufactured dielectric block / plate. The support portion 34 may also be a component attached to the surface of the circuit board 3. The support portion 34 may simply be fixed to the surface of the circuit board 3. From the viewpoint of reducing the height (thickness) of the device by utilizing the wavelength shortening effect, the support portion 34 preferably has a high dielectric constant. Examples of methods for patterning the antenna 4 on the surface of the support portion 34 include electroplating, metal vapor deposition, and application of conductive paint. The conductor pattern corresponding to the substrate parallel portion 42 may be formed inside the support portion 34 .

[0039] The antenna 4 is excited at the target frequency because the total length of the standing portion 41 and the board parallel portion 42 is electrically set to λ / 4. The current component flowing through the standing portion 41 contributes to the radiation of board vertical polarization, which is a linear polarization in which the vibration direction of the electric field is perpendicular to the circuit board 3. The current component flowing through the board parallel portion 42 contributes to the radiation of board parallel polarization, which is a linear polarization in which the vibration direction of the electric field is parallel to the circuit board 3. In other words, the antenna 4 is configured as an inverted L antenna, and therefore functions as an antenna that can transmit and receive both board vertical polarization and board parallel polarization.

[0040] Because the standing portion 41 corresponds to part of a monopole antenna, the gain of the substrate vertically polarized wave is approximately uniform in all directions perpendicular to the standing portion 41. In other words, it has omnidirectionality in the XY plane. The substrate parallel portion 42 also has radiation characteristics similar to those of a monopole antenna. Specifically, it can radiate substrate horizontally polarized wave in all directions perpendicular to the substrate parallel portion 42, including the positive and negative directions of the Z axis. Note that while the characteristics of the antenna 4 have been described here from the perspective of radio wave radiation, the gain characteristics when receiving radio waves are also similar to the radiation characteristics due to the reversibility of transmission and reception. Hereinafter, an antenna capable of transmitting and receiving substrate vertically polarized wave will also be referred to as a parallel-polarized antenna 4x. The antenna 4 including the substrate parallel portion 42 corresponds to a parallel-polarized antenna 4x. An antenna capable of transmitting and receiving substrate vertically polarized wave will also be referred to as a vertically polarized antenna.

[0041] The gain ratio between the substrate-parallel polarization and the substrate-parallel polarization is derived from the aspect ratio of the L-shaped element, i.e., the ratio of the lengths of the standing portion 41 and the substrate-parallel portion 42. Increasing the length of the substrate-parallel portion 42 improves the gain of the substrate-parallel polarization. Therefore, it is preferable that the length of the substrate-parallel portion 42 is set to be equal to or greater than the length of the standing portion 41. For example, the length ratio of the standing portion 41 to the substrate-parallel portion 42 is set to 1:3, 1:2, 2:3, 3:4, 1:1, etc. Of course, in other embodiments, the substrate-parallel portion 42 may be set to be shorter than the standing portion 41. For example, the length ratio of the standing portion 41 to the substrate-parallel portion 42 may be set to 3:1, 2:1, 3:2, 3:2, 4:3, etc.

[0042] The shorter the standing portion 41, the smaller the distance between the board parallel portion 42 and the upper surface of the circuit board 3. From the viewpoint of mountability in a vehicle, it is preferable to design the height to be low. On the other hand, as the standing portion 41 is shortened, the distance between the vehicle body metal serving as the attachment target portion 200 and the board parallel portion 42 becomes smaller, as will be described later, and the metal serving as the attachment target portion 200 acts as a reflector, increasing the risk of narrowing the directivity. It is preferable that the standing portion 41 be set to a value as long as possible within a range in which the gain of the board parallel polarization is at a predetermined required level.

[0043] As shown in FIG. 2 , the antenna 4 is disposed on the positive side of the X-axis relative to the control circuit 32, with the board parallel portion 42 parallel to the Y-axis in a top view. For example, the antenna 4 is disposed within 2 cm from the edge of the circuit board 3 on the positive side of the X-axis, with the board parallel portion 42 parallel to the Y-axis. Note that the positional relationship of the components on the circuit board 3, in other words, the layout, can be changed as appropriate. For example, the antenna 4 may be disposed within 2 cm from the edge of the circuit board 3 on the positive side of the Y-axis, with the board parallel portion 42 parallel to the X-axis. In the following description, the term "board parallel portion 42" can be read as "parallel polarized antenna 4x."

[0044] The circuit board 3 includes a ground layer, which is a conductor layer electrically connected to the ground side line of the power cable via a connector or the like. The ground layer provides a ground potential for various circuits. Here, as an example, the ground layer is formed on the lower surface of the circuit board 3. The conductor pattern formed on the ground layer is referred to as a ground pattern 35. The ground pattern 35 is a plate-shaped conductor member. Here, the plate-shaped member also includes a thin film such as copper foil. The ground pattern 35 corresponds to the ground portion.

[0045] 4, the ground pattern 35 is formed over most of the lower surface of the circuit board 3. However, the ground pattern 35 is formed so as to avoid the portion facing the board parallel portion 42. More specifically, the ground pattern 35 is formed so as to be spaced 2 mm or more from the portion overlapping with the board parallel portion 42. For example, the ground pattern 35 has a slot portion 351 as a notch at the position overlapping with the board parallel portion 42.

[0046] The slot portion 351 is preferably larger than the board parallel portion 42, but this is not necessarily the case. The ground pattern 35 may be formed so as to overlap a portion of the board parallel portion 42. For example, to stabilize the operation of the antenna 4, the ground pattern 35 may be formed in a portion that overlaps with the lower end of the standing portion 41 in a top view. It is sufficient that the slot portion 351 is formed so that more than half of the board parallel portion 42 does not overlap with the ground pattern 35. Note that FIG. 4 is a diagram schematically showing the positional relationship of each component when viewed from the bottom of the circuit board 3. The hatched portion in FIG. 4 indicates the portion where the ground pattern 35 is provided.

[0047] In a configuration in which the ground pattern 35 is formed so as to avoid the portion overlapping with the board parallel portion 42, as shown in FIG. 5 , the board-parallel polarized waves radiated from the board parallel portion 42 can penetrate and propagate below the circuit board 3. Furthermore, the distance from the nearest conductor plate below the board parallel portion 42 to the board parallel portion 42 can be extended. Furthermore, the smaller the distance between the board parallel portion 42 and the conductor plate, the more likely the effective line-of-sight angle becomes narrower due to the influence of reflections from the conductor plate. In response to this situation, the above configuration increases the distance between the board parallel portion 42 and the conductor plate, thereby reducing the risk of the line-of-sight angle becoming narrower. Note that, as a premise, no conductor is formed as a conductor layer at least in the portion of the circuit board 3 that overlaps with the board parallel portion 42. An internal conductor layer may be formed as appropriate in the area of ​​the circuit board 3 that does not overlap with the board parallel portion 42.

[0048] The ground pattern 35 corresponds to a ground plane for the antenna 4. In one aspect, the circuit board 3 corresponds to a configuration in which an inverted-L antenna is disposed on one side of a dielectric plate having a predetermined thickness and relative dielectric constant, and a ground plane is provided on the opposite side. Of course, the ground pattern 35 serving as the ground plane may be formed inside the board. The configuration disclosed here is one example, and the circuit board 3 may, for example, have a power supply layer or the like as another internal conductor layer.

[0049] The lower case 1 is a member that covers the circuit board 3 from below and accommodates and supports the circuit board 3. The lower case 1 corresponds to a member that provides the bottom of the housing of the vehicle radio device 100. Such a lower case 1 corresponds to a configuration that protects the lower surface of the circuit board 3. The lower case 1 is formed using a synthetic resin such as polycarbonate (PC). The lower case 1 is formed, for example, in the shape of a flat plate.

[0050] The lower case 1 is formed in a flat (i.e., shallow) box shape with an open upper surface. That is, the lower case 1 includes a bottom surface 11 that faces the circuit board 3 at a predetermined distance, and a lower wall portion 12 that extends upward from the edge of the bottom surface 11. Note that the lower wall portion 12 is an optional element and may be omitted. The bottom surface 11 is formed with through holes 13 for passing screws at positions corresponding to the screw holes 33 formed in the circuit board 3. For example, the through holes 13 for screw fastening are provided in the four corners of the bottom surface 11.

[0051] As described above, various resins such as polycarbonate can be used as the material of the lower case 1. The material of the lower case 1 may be a resin material that can maintain a desired strength within the expected temperature range (hereinafter referred to as the operating temperature range) in which the vehicle wireless device 100 is used. The operating temperature range is set to, for example, -20°C or higher and 120°C or lower.

[0052] As another example, the lower case 1 may be made of metal, as will be described later. A metal lower case 1 is expected to have the effect of improving the strength of the device and the stability of the electrical connection with the vehicle body, in other words, the circuit ground. Furthermore, the lower case 1 may be realized by combining a metal member and a resin. For example, the lower case 1 may have a configuration in which a metal frame is covered with resin, in other words, a configuration in which a metal frame is embedded inside a resin member that provides the exterior shape. The portion of the lower case 1 that faces the board parallel portion 42, which will be described later, is preferably made of resin so that radio waves can pass through.

[0053] The upper case 2 is a member that covers the circuit board 3 from above and houses and protects the circuit board 3. The upper case 2 is made of a resin material such as polycarbonate to allow radio waves to pass through. The upper case 2 is configured to be able to fit into the lower case 1 while housing the circuit board 3.

[0054] The upper case 2 is formed in a generally box-like shape with an open lower surface. Specifically, it includes a ceiling portion 21 that faces the upper surface of the circuit board 3 at a predetermined distance, and side wall portions 22 that extend downward from the edges of the ceiling portion 21. The ceiling portion 21 corresponds to a configuration that provides the upper surface of the housing of the vehicle wireless device 100. The side wall portions 22 are sized and shaped so that their lower ends fit together with the upper end of the bottom wall portion 12. The outer surfaces of the side wall portions 22 correspond to the side surfaces.

[0055] A notch 23 is formed in the side wall 22 of the upper case 2 in a portion corresponding to the connector 31 to expose the vicinity of the tip of the connector 31. Furthermore, a marker 24 indicating the position of the board parallel portion 42 is formed in the side wall 22 of the upper case 2 in a portion located to the side of the board parallel portion 42. The marker 24 may be a printed line or a three-dimensional structure such as a step or groove. By providing the marker 24 on the side surface of the upper case 2, it is easy to adjust the board parallel portion 42 to a position λ / 4 away from the surface of the attachment target portion 200 during attachment. Note that the marker 24 is an optional element and may be omitted. In addition, a step or the like with a hole for accommodating a screw is formed on the inside of the upper case 2 at a position corresponding to the screw hole 33.

[0056] The case formed by combining the lower case 1 and the upper case 2 is configured to have an electrical thickness of λ / 4 or more at least in the portion where the antenna 4 is formed, due to the wavelength shortening effect provided by the circuit board 3 and the seal material Sg. In addition, metal fittings for attaching the vehicular wireless device 100 to the vehicle body may be attached to the side wall portion 22 or the bottom surface portion 11. A variety of attachment mechanisms can be used to fix the vehicular wireless device 100 to the vehicle body.

[0057] <About vehicle installation and effects> Since the above-described vehicle radio device 100 is mounted with the circuit board 3 facing the mounting target 200, the substrate parallel polarization corresponds to a linear polarization in which the electric field vibration direction is also parallel to the surface of the mounting target 200. In other words, the parallel polarization antenna corresponds to an antenna that can transmit and receive linear polarization in which the electric field vibration direction is parallel to the metal surface of the mounting target 200. Furthermore, the substrate vertical polarization corresponds to a linear polarization in which the electric field vibration direction is also perpendicular to the mounting target 200.

[0058] The developers of the present disclosure conducted simulations under various conditions in which the distance between the vehicle body and the antenna and the mounting position were changed, and found that, compared to a vertically polarized antenna, the line of sight tends to become narrower as the distance from the parallel polarized antenna 4x to the mounting target portion 200 becomes smaller. More specifically, they found that the shorter the distance between the parallel polarized antenna 4x and the vehicle body, the less likely it is that radio waves will bend around to the back side of the mounting target portion 200.

[0059] Figures 6 and 7 show the results of a simulation of the propagation strength of direct waves when a dipole antenna 4d, serving as a parallel polarized antenna 4x, is attached to the interior surface of a metal C-pillar located on the right side of the vehicle, oriented along the vehicle height direction. Figure 6 shows the strength distribution when the distance between the dipole antenna 4d, serving as a parallel polarized antenna, and the C-pillar surface is set to 9 mm (equivalent to 0.075λ). Figure 7 shows the strength distribution when the distance between the dipole antenna 4d and the C-pillar surface is set to 60 mm (equivalent to 0.5λ).

[0060] As a simulation condition, the dipole antenna 4d is mounted at a height of 110 cm from the ground. Figures 6 and 7 show the maximum electric field strength for a period of 5 nanoseconds from the start of radio wave emission on a plane 110 cm above the ground. If the propagation strength observation period were set to 5 nanoseconds or longer, the effects of reflected waves from metal parts of the vehicle body 1.5 m or more away from the mounting target 200, such as the left C-pillar, would be mixed in, making it difficult to determine the propagation range of the direct wave. For this reason, the propagation strength observation period is set to within 5 nanoseconds from the start of radio wave emission.

[0061] Pmn in Figures 6 and 7 represents the operating lower limit, which is the lowest limit of the reception strength at which the mobile terminal can successfully decode the signal from the antenna 4. The operating lower limit Pmn corresponds to the lowest signal level at which communication between the mobile terminal and the vehicular radio device 100 is established. The operating lower limit Pmn varies depending on the power at which the vehicular radio device 100 transmits the radio signal and the reception sensitivity. Depending on the settings of the transmission power, reception sensitivity, etc., the operating lower limit Pmn can be 130 dBuV / m, 110 dBuV / m, or 80 dBuV / m. The density of the dot patterns in Figures 6 and 7 indicates the propagation strength. The higher the density of the dot pattern, the stronger the propagation strength. Naturally, areas where the propagation strength is higher than the operating lower limit Pmn are areas where communication is more stable.

[0062] As can be seen by comparing Figures 6 and 7, the electric field strength near the door outside the vehicle cabin is stronger in Figure 7 than in Figure 6. This is presumably because the closer the parallel polarized wave antenna is to the C-pillar serving as the mounting target 200, the more likely the radiated parallel polarized wave from the substrate is to be repelled toward the inside of the vehicle cabin by the metal surface, making it less likely to bend around to the outside of the vehicle cabin through the window 210. Furthermore, as shown in Figures 7 and 6, the closer the dipole antenna 4d is to the C-pillar, the narrower the angular range in which the signal propagates while maintaining an intensity above a predetermined value. This is presumably because the C-pillar located behind the dipole antenna 4d acts as a reflector.

[0063] In the above, an example has been described in which the mounting target 200 is assumed to be a reflector of the radio waves emitted by the parallel polarized antenna 4x, but a conductive plate such as the ground pattern 35 can also act as a reflector. In order to maintain good communication performance of the parallel polarized antenna, it is preferable to place the parallel polarized antenna 4x as far away as possible from conductive plates that can act as reflectors.

[0064] The vehicle radio device 100 of this embodiment has been made in consideration of the above-mentioned circumstances. That is, because the ground pattern 35 is formed so as to avoid the portion facing the board parallel portion 42 and the lower case 1 is made of resin, the back conductor plate BM for the board parallel portion 42 becomes the attachment target portion 200. Here, the back conductor plate BM refers to the conductor plate that is closest to the board parallel portion 42 and directly below the board parallel portion 42. Here, the conductor plate also includes a thin-film conductor having a certain area, such as the ground pattern 35, which is patterned by plating or the like.

[0065] According to the above configuration, the distance from the board parallel portion 42 to the rear conductor plate BM can be made longer than when the ground pattern 35 is formed directly below the board parallel portion 42 or when the lower case 1 is made of metal.

[0066] Specifically, when the ground pattern 35 is formed directly below the board parallel portion 42, the ground pattern 35 corresponds to the rear conductor plate BM. Therefore, the distance from the board parallel portion 42 to the rear conductor plate BM is Dm+Dn as shown in FIG. 8. Dm is the distance from the board parallel portion 42 to the upper side of the circuit board 3. Dn indicates the electrical distance according to the thickness of the circuit board 3. Dn can be calculated as an effective length that takes into account the wavelength shortening effect of the dielectric.

[0067] Furthermore, if the ground pattern 35 is not formed directly below the board parallel portion 42 but the lower case 1 is made of metal, the lower case 1 corresponds to the rear conductor plate BM. Therefore, the distance from the board parallel portion 42 to the rear conductor plate BM is Dm+Dn+Dp. Dp refers to the distance from the lower surface of the circuit board 3 to the bottom portion 11.

[0068] In contrast to these assumed configurations, according to the above embodiment, the distance from the board parallel portion 42 to the rear conductor plate BM is the distance Ds from the board parallel portion 42 to the attachment target portion 200. In other words, it is longer by the thickness of the bottom surface portion 11 and the gap between the surface of the attachment target portion 200 and the bottom surface portion 11. Therefore, compared to the assumed configurations described above, the influence of the rear conductor plate BM on the formation of the communication area can be reduced, and as a result, the communication area can be formed well. The influence of the rear conductor plate BM refers to, for example, the reflection of radio waves, which causes the effective communication area to have a sharper angle or makes it difficult for the radio waves to reach the back side of the attachment target portion 200.

[0069] The developers of the present disclosure discovered that setting the distance from the board parallel portion 42 to the back conductor plate BM to λ / 4 or more increases the gain in the direction along the attachment target portion 200 and the amount of wraparound to the back side of the attachment target portion 200. Therefore, it is preferable that the board parallel portion 42 be attached so as to be spaced λ / 4 or more from the vehicle body metal 8. In other words, it is preferable that the attachment be performed in a manner that satisfies the relationship Ds > λ / 4. Note that the back side of the attachment target portion 200 refers to the outside of the vehicle cabin when, for example, the vehicle wireless device 100 is attached to the interior surface of the vehicle body metal. Furthermore, when the vehicle wireless device 100 is attached to the exterior surface of the vehicle body metal, the back side of the attachment target portion 200 refers to the inside of the vehicle cabin.

[0070] However, if there are no markers 24 on the outer surface of the upper case 2, the specific position of the board parallel portion 42 inside the case is unclear. This can make it difficult for an installer of the vehicular radio apparatus 100 to install the vehicular radio apparatus 100 in a manner that satisfies the relationship Ds>λ / 4. To address this issue, the configuration in which the markers 24 are provided on the outer surface of the upper case 2 makes it easier to install the vehicular radio apparatus 100 on the installation target portion 200 so that the relationship Ds>λ / 4 is satisfied. In other words, it becomes easier to maintain an appropriate distance and improves installation workability.

[0071] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. Various modifications and a second embodiment described below are also included within the technical scope of the present disclosure. Furthermore, various modifications other than those described below can be implemented without departing from the gist of the present disclosure. For example, the various supplements and modifications described below can be implemented in appropriate combinations as long as no technical contradictions arise. Note that components having the same functions as the components described above are given the same reference numerals, and their description may be omitted. Furthermore, when only a portion of the configuration is mentioned, the above description can be applied to the other portions.

[0072] In the above-described embodiment, the lower case 1 is made of resin, but the lower case 1 may also be made of metal. When the lower case 1 is made of metal and the ground pattern 35 is formed so as to avoid the board parallel portion 42 as shown in Fig. 9, it is preferable that the distance Dt from the board parallel portion 42 to the lower case 1 is set to be electrically λ / 4 or more. The above-described configuration corresponds to a configuration in which a conductive plate such as the ground pattern 35 is not provided in the region below the board parallel portion 42 that is within λ / 4.

[0073] Since λ / 4 in a vacuum or in air corresponds to 30 mm, if the wavelength shortening effect is only applied to the inside of the circuit board 3, the height of the device will increase. Since the space available for mounting the vehicular radio device 100 in a vehicle is limited, it is preferable that the vehicular radio device 100 be made as thin as possible.

[0074] For this reason, as shown in FIG. 10, a support portion 34 made of a dielectric material having a dielectric constant equal to or greater than a predetermined value may be inserted between the substrate parallel portion 42 and the circuit board 3. This configuration allows for a longer effective length from the substrate parallel portion 42 to the bottom portion 11 (rear conductor plate BM) than the configuration shown in FIG. 9 in which the space between the substrate parallel portion 42 and the circuit board 3 is hollow. As a result, the height of the device required to electrically set the distance Dt to λ / 4 or greater can be reduced. In one respect, the configuration shown in FIG. 10 corresponds to the configuration in which the antenna 4 is formed on the surface of the support portion 34, as illustrated in FIG. 3. The space between the substrate parallel portion 42 and the circuit board 3 may be partially hollow.

[0075] Furthermore, if a dielectric material is inserted between the board parallel portion 42 and the circuit board 3, the electrical distance Dt increases. Based on this perspective, the inside of the case may be filled with a gel-like sealant Sg as shown in FIG. 11. The sealant Sg corresponds to a sealing material. A variety of materials can be used for the sealant Sg, including urethane resins such as polyurethane prepolymers, epoxy resins, and silicone resins. A configuration in which the sealant Sg is filled inside the case not only reduces the height of the device and the narrowing of the communication area, but also improves waterproofness, dustproofness, and vibration resistance. The control circuit 32 is not shown in FIG. 11.

[0076] Although the above description has been made on the case where only one circuit board 3 is housed in the case, this is not limiting. As shown in Fig. 12, the vehicle radio device 100 may include a first board 3A on which the antenna 4 and part of the control circuit 32 are formed, and a second board 3B on which the remaining part of the control circuit 32 is formed. The second board 3B is disposed below the first board 3A in a position facing the first board 3A.

[0077] A ground pattern 35A is formed on the lower surface of the first substrate 3A so as to avoid the area that overlaps with the board parallel portion 42 in a top view. Meanwhile, a ground pattern 35B is formed on the lower surface of the second substrate 3B, also in the area that overlaps with the board parallel portion 42 in a top view. The second substrate 3B is preferably disposed in a position where the distance from the board parallel portion 42 to the ground pattern 35B is electrically λ / 4 or more. The ground pattern 35B provided on the second substrate 3B corresponds to the second substrate ground portion.

[0078] Furthermore, if the thickness of the circuit board 3 is electrically λ / 4 or more, the ground pattern 35 may also be formed on the lower surface of the circuit board 3 in a portion facing the board parallel portion 42 .

[0079] Furthermore, although the above example discloses an embodiment in which antenna 4 functioning as parallel polarized wave antenna 4x is an inverted L antenna erected on circuit board 3, the type / shape of antenna 4 is not limited to this.

[0080] For example, as shown in FIG. 13 , the antenna 4 and the parallel-polarized antenna 4x may be dipole antennas. The dipole antenna serving as the parallel-polarized antenna 4x is disposed, for example, on the upper surface of the support portion 34. In the embodiment shown in FIG. 13 , the entire dipole antenna corresponds to the board parallel portion. In this case, the support portion 34 is formed in a rectangular parallelepiped shape with a longitudinal length of λ / 2 or more. Note that the support portion 34 may have any shape that allows the dipole antenna to be mounted thereon. If a structure that reduces the size of the dipole antenna is adopted, such as when the dipole antenna is partially bent or formed in a meandering shape, the support portion 34 may have a length of λ / 2 or less. Furthermore, the dipole antenna serving as the antenna 4 does not necessarily need to be formed on the support portion 34 that protrudes from the surface of the circuit board 3. The dipole antenna serving as the antenna 4 may be formed on the upper surface of the circuit board 3.

[0081] Furthermore, antenna 4 may be configured as an inverted-F antenna as shown in FIG. 14. The inverted-F antenna serving as antenna 4 is disposed, for example, on the upper surface of support portion 34. In the position shown in FIG. 14, the entire inverted-F antenna corresponds to the parallel portion of the board. Support portion 34 may have any shape that allows the inverted-F antenna serving as antenna 4 to be mounted thereon. Note that the inverted-F antenna serving as antenna 4 does not need to be formed on support portion 34 either. The inverted-F antenna serving as antenna 4 may also be formed on the upper surface of circuit board 3. Note that although FIGS. 13 and 14 are not cross-sectional views, antenna 4 is hatched with a diagonal line pattern to clearly indicate where antenna 4 is formed.

[0082] The antenna 4 may be configured as a three-dimensional inverted-F antenna as shown in FIG. 15 . The three-dimensional inverted-F antenna serving as the antenna 4 is attached to the circuit board 3, for example, at the end of the circuit board 3 on the positive Y-axis side, so as to stand upright from the circuit board 3. That is, the three-dimensional inverted-F antenna serving as the antenna 4 is formed in an inverted-F shape including a first standing portion 41a having a feed point at its lower end, a second standing portion 41b having its lower end connected to the ground pattern 35, and a board parallel portion 42. The first standing portion 41a and the second standing portion 41b are both linear conductors standing upright on the circuit board 3. The first standing portion 41a and the second standing portion 41b may be configured to stand on their own with respect to the circuit board 3, or may be configured to be supported by the support portion 34. They may be formed on the surface of or inside the support portion 34.

[0083] The length of the substrate parallel portion 42 is set to an electrical length of λ / 4. The first upright portion 41a and the second upright portion 41b are equal, and their lengths can be any value. In the shape shown in FIG. 15, the substrate parallel portion 42 operates to transmit and receive substrate-parallel polarized waves, while the first upright portion 41a operates to transmit and receive substrate-vertical polarized waves. In other words, the three-dimensional inverted-F antenna shown in FIG. 15 can transmit and receive both substrate-parallel polarized waves and substrate-vertical polarized waves with a single element.

[0084] 1 and the like, the board parallel portion 42 is supported by a single upright portion 41, whereas in the three-dimensional inverted-F antenna, the board parallel portion 42 is supported by two portions, the first upright portion 41a and the second upright portion 41b. Therefore, a configuration employing a three-dimensional inverted-F antenna as the antenna 4 can increase the strength of fixing the antenna 4 to the circuit board 3 compared to a configuration employing a three-dimensional inverted-L antenna. In particular, when the antenna 4 is mounted in a vehicle, vibrations of the vehicle body act on the antenna 4. If the fixing strength between the circuit board 3 and the antenna 4 is insufficient, the antenna 4 may become detached from the circuit board 3 due to vehicle body vibrations. For these reasons, a three-dimensional inverted-F antenna is preferable to a three-dimensional inverted-L antenna for the antenna 4.

[0085] Furthermore, in the three-dimensional inverted-F antenna, it is preferable that more than half of the board parallel portion 42 is arranged so that it does not overlap with the ground pattern 35. In other words, it is preferable that the antenna 4 is arranged so that the majority of the board parallel portion 42 is located above the non-ground forming portion 36. This is because if the ground pattern 35 is present below the board parallel portion 42, the electromagnetic waves resulting from the current flowing in the board parallel portion 42 and the electromagnetic waves resulting from the current flowing in the ground pattern 35 will act to cancel each other out, reducing the gain of the board-parallel polarized waves.

[0086] The dashed line in Fig. 15 indicates the area where ground pattern 35 is formed. Fig. 15 shows a configuration in which part of the section of board-parallel portion 42 closer to the open end than first upright portion 41a is arranged to be flush with ground pattern 35. Of course, it is preferable that board-parallel portion 42 be located as high above non-ground forming portion 36 as possible.

[0087] By the way, an inverted-F radiating element looks like an F when viewed from the other side. The term "inverted-F antenna" follows the conventional name in the antenna technology field. The term "inverted-F antenna" also includes non-inverted F-shaped antennas. In other words, an inverted-F antenna can also be called an F-shaped antenna. Similarly, the term "inverted-L antenna" also includes non-inverted L-shaped antennas.

[0088] Additionally, the antenna 4 may have any structure as long as it is configured to be able to receive waves polarized parallel to the substrate, and various structures such as a patch antenna may be employed. The antenna 4 may be provided on the circuit board 3 in a position that allows it to receive waves polarized parallel to the substrate. As a method for feeding power to the antenna 4, a direct feeding method in which power is fed directly using a conductive pin or conductor pattern, as well as an electromagnetic coupling feeding method, may be employed.

[0089] 13 and 14 show a configuration in which the antenna 4 is provided near the end of the circuit board 3 on the positive side of the Y axis, but as mentioned above, the position of the antenna 4 can be changed as appropriate. The antenna 4 may also be patterned on the inner surface of the ceiling portion 21. The antenna 4 formed inside the ceiling portion 21 can be fed using a feeder line formed along the inner surface of the side wall portion 22, for example. With this configuration, the antenna 4 can be placed at the highest position inside the case, further reducing the influence of the back conductor plate BM.

[0090] In the above-described embodiment, as illustrated in FIG. 4 , a configuration was disclosed in which a slot portion 351 was provided as a local cutout in the ground pattern 35. However, the configuration for transmitting radio waves from the board parallel portion 42 downward through the circuit board 3, in other words, the configuration for extending the distance of the board parallel portion 42 from the rear conductor plate BM, is not limited to this. For example, as illustrated in FIG. 16 , a non-ground forming portion 36, which is an area where the ground pattern 35 is not provided, may be set to be sufficiently larger than the antenna 4 for parallel polarization. Note that FIG. 16 illustrates an example in which an inverted-F antenna is used as the antenna 4. For convenience, the area where the ground pattern 35 is formed is indicated by diagonal hatching.

[0091] It is preferable that the ground pattern 35 is formed at least in an area corresponding to the area below the control circuit 32. The slot portion 351 described above also corresponds to the non-ground forming portion 36. The above embodiment corresponds to a configuration in which the board parallel portion 42 / parallel polarization antenna 4x is formed above the non-ground forming portion 36. The position and shape of the non-ground forming portion 36 can be changed as appropriate. The non-ground forming portion 36 may be rectangular, circular, or triangular.

[0092] 17, in addition to the parallel polarization antenna 4x, a vertical polarization antenna 5 may be provided on the circuit board 3. The vertical polarization antenna 5 is configured as, for example, a zero-order resonance antenna. That is, the vertical polarization antenna 5 includes an opposing conductor plate 51 which is a flat metal conductor arranged to face the ground pattern 35, and a short-circuit portion 52 which electrically connects the center of the opposing conductor plate 51 to the ground pattern 35. The size of the opposing conductor plate 51 is configured so that it resonates in parallel at a target frequency due to the inductance of the short-circuit portion 52 and the electrostatic capacitance formed between the ground pattern 35 and the opposing conductor plate 51.

[0093] The zeroth-order resonant antenna has a mushroom structure, which is the basic structure of metamaterials, and is equivalent to an antenna that utilizes the phenomenon of resonating at a frequency where the phase constant β becomes zero (0) among the dispersion characteristics of metamaterials. A zeroth-order resonant antenna can also be called a metamaterial antenna. Vertically polarized antenna 5, which serves as a zeroth-order resonant antenna, is characterized by operating by LC parallel resonance between the capacitance formed between ground pattern 35 and opposing conductor plate 51 and the inductor provided in short-circuit portion 52.

[0094] Fig. 17 illustrates a configuration in which an L-shaped antenna patterned on the upper side of circuit board 3 is used as parallel polarized antenna 4x. Fig. 18 is a cross-sectional view taken along line XVIII-XVIII shown in Fig. 17. In order to clearly show each component in Fig. 18, the scale of the drawing has been changed from that of Fig. 19.

[0095] 17, the dashed line indicated by 35 indicates the area where ground pattern 35 is formed. Ground pattern 35 is not formed in the area overlapping with parallel polarized wave antenna 4x, but is formed in the area overlapping with opposing conductor plate 51. In other words, parallel polarized wave antenna 4x is disposed in the area where ground pattern 35 is not formed, while opposing conductor plate 51 is disposed in the area where ground pattern 35 is formed.

[0096] The opposing conductor plate 51 is a plate-shaped conductive member made of a conductive material such as copper. As mentioned above, the plate-shaped member here also includes a thin film such as copper foil. The opposing conductor plate 51 is disposed so as to face the ground pattern 35 via the dielectric layer of the circuit board 3. The opposing conductor plate 51 may also be patterned on the upper surface of the circuit board 3.

[0097] The opposing conductor plate 51 is disposed opposite the ground pattern 35, thereby forming a capacitance according to the area of ​​the opposing conductor plate 51 and the distance between the opposing conductor plate 51 and the ground pattern 35. The opposing conductor plate 51 is sized to form a capacitance that resonates in parallel with the inductance of the short-circuiting portion 52 at the main target frequency. The area of ​​the opposing conductor plate 51 may be appropriately designed to provide a desired capacitance. The desired capacitance is a capacitance that operates at the main target frequency in cooperation with the inductance of the short-circuiting portion 52. Note that if the operating frequency is f, the inductance of the short-circuiting portion 52 is Ls, and the capacitance formed between the opposing conductor plate 51 and the ground pattern 35 is C, then the relationship f≒1 / {2π√(Ls·C)} holds. Those skilled in the art can determine the appropriate area of ​​the opposing conductor plate 51 based on this relationship.

[0098] For example, the opposing conductor plate 51 is formed in a square shape with each side measuring 25 mm. Of course, the length of each side of the opposing conductor plate 51 can be changed as appropriate and may be 20 mm, 30 mm, 40 mm, etc. The dimensions of the opposing conductor plate 51 can be determined in consideration of the target wavelength and the wavelength shortening effect of the dielectric provided in the circuit board 3. The planar shape of the opposing conductor plate 51 may be a circle, a regular octagon, a regular hexagon, etc. Furthermore, the opposing conductor plate 51 may be a rectangle, an elongated ellipse, etc.

[0099] The short-circuiting portion 52 is a conductive member that electrically connects the ground pattern 35 and the opposing conductive plate 51. The short-circuiting portion 52 may be realized using a conductive pin (hereinafter, short pin). The inductance of the short-circuiting portion 52 can be adjusted by adjusting the diameter and length of the short pin that serves as the short-circuiting portion 52. The radius (r) of the short-circuiting portion 52 is set to, for example, 3 mm. Of course, the radius may be 1 mm, 2 mm, or 5 mm.

[0100] The short-circuit portion 52 has an inductance according to its diameter and length. The inductance value of the short-circuit portion 52 can be changed by adjusting the diameter (in other words, thickness) and length in the Z direction of the short-circuit portion 52, for example.

[0101] The short-circuit portion 52 may be a linear member having one end electrically connected to the ground pattern 35 and the other end electrically connected to the opposing conductor plate 51. A via hole in the circuit board 3 or the like can be used as the short-circuit portion 52.

[0102] The short-circuit portion 52 is provided so as to be located, for example, at the center of the opposing conductor plate 51. Note that, when the opposing conductor plate 51 is, for example, square or rectangular, the center of the opposing conductor plate 51 corresponds to the intersection of the diagonals. In the present disclosure, the center of the opposing conductor plate 51 will hereinafter also be referred to as the conductor plate center.

[0103] The position where the short-circuit portion 52 is formed does not need to coincide strictly with the center of the conductor plate. The short-circuit portion 52 may be shifted from the center of the conductor plate by several millimeters. The short-circuit portion 52 only needs to be formed in the central region of the opposing conductor plate 51. The central region of the opposing conductor plate 51 refers to the region inside the line connecting the points that divide the distance from the center of the conductor plate to the edge at a ratio of 1:5. From another perspective, the central region corresponds to the region where concentric figures obtained by reducing the opposing conductor plate 51 to about one-sixth of their original size overlap.

[0104] The feeding point is placed at a position where impedance matching can be achieved on the opposing conductor plate 51. Impedance matching here means that the impedance value on the signal sending side and the impedance value on the signal receiving side are approximately the same.

[0105] As described above, by including the vertically polarized antenna 5 in addition to the parallel polarized antenna 4x, the vehicle radio device 100 can transmit and receive two types of radio waves whose polarization planes are orthogonal to each other. This enables polarization diversity and improves robustness.

[0106] Furthermore, the position of a mobile terminal such as a smartphone, which is assumed to be one of the communication partners of the vehicle radio apparatus 100, relative to the vehicle radio apparatus 100 changes depending on how the user holds it. Therefore, the polarization plane of the radio waves from the mobile terminal that arrive at the vehicle radio apparatus 100 may vary. In light of this situation, a configuration including a vertically polarized antenna 5 in addition to a parallel polarized antenna 4x makes it possible to better receive radio signals from the mobile terminal carried by the user. As a result, it may be possible to more accurately detect the approach of the user (mobile terminal) to the vehicle and the user's position relative to the vehicle.

[0107] Note that the substrate vertically polarized wave propagates along the back conductor plate BM regardless of the distance from the back conductor plate BM. Therefore, from the viewpoint of improving the amount of light that wraps around to the back side of the back conductor plate BM, it is not necessary to consider the distance between the vertically polarized antenna 5 and the back conductor plate BM.

[0108] Furthermore, if the thickness of the circuit board 3 is electrically λ / 4 or greater, a ground pattern may also be formed on the lower surface of the circuit board 3 in a portion overlapping with the parallel polarization antenna 4x. If the thickness of the circuit board 3 is electrically λ / 4 or greater, for example, as shown in FIG. 19 , a ground pattern 35β for the vertical polarization antenna 5 may be provided on a layer different from the ground pattern 35α for the parallel polarization antenna 4x. The ground patterns 35α and 35β may be electrically connected by buried vias or blind vias (not shown). Dw in FIG. 19 indicates the distance from the upper surface to the lower surface of the circuit board 3, i.e., the thickness of the circuit board 3, and satisfies the electrical relationship Dw > λ / 4. Dv in FIG. 19 indicates the distance between the opposing conductor plate 51 and the ground pattern 35β. The distance Dv may be set to create the capacitance required to generate LC parallel resonance at the target frequency.

[0109] Alternatively, the vertically polarized antenna 5 may be a monopole antenna erected on the circuit board 3. A variety of antenna structures can be employed for the vertically polarized antenna 5. However, a configuration employing a zero-order resonant antenna as the vertically polarized antenna 5 has the advantage of being able to reduce the height of the device compared to a configuration using a monopole antenna or the like. The erected portion 41 of the three-dimensional antenna shown in FIG. 1 etc. can also be used as the vertically polarized antenna 5. The antenna 4 including the erected portion 41 and the board parallel portion 42 corresponds to an antenna that functions as both the vertically polarized antenna 5 and the parallel polarized antenna 4x. The erected portion 41 here also includes the first erected portion 41a.

[0110] <Supplementary information on the operating principle of zero-order resonance antennas> Opposing conductor plate 51 constituting the zero-order resonant antenna is designed to have an area that forms a capacitance that resonates in parallel at a desired frequency (operating frequency) with the inductance of short-circuit portion 52. Opposing conductor plate 51 is short-circuited to ground pattern 35 at short-circuit portion 52 provided in its central region.

[0111] Therefore, when power of the operating frequency is input from the feed point to the opposing conductor plate 51, LC parallel resonance occurs due to energy exchange between the inductor and capacitor, and an electric field perpendicular to the ground pattern 35 is generated between the ground pattern 35 and the opposing conductor plate 51. In other words, an electric field is generated in the Z-axis direction. This perpendicular electric field propagates from the short-circuit portion 52 toward the edge of the opposing conductor plate 51, and at the edge of the opposing conductor plate 51 becomes a wave polarized vertically to the substrate and propagates through space.

[0112] Here, the propagation direction of the vertical electric field generated by the LC parallel resonance is symmetrical with respect to the short-circuit part 52, and therefore has the same degree of gain in all directions perpendicular to the short-circuit part 52. In other words, one zero-order resonance antenna has directivity in all directions from the central region of the opposing conductor plate 51 toward the edge.

[0113] Furthermore, the operation of the antenna when it transmits (radiates) radio waves and the operation when it receives radio waves are reversible. Although the above description has been given using the example of radiating radio waves, the above configuration can also receive substrate vertically polarized waves.

[0114] <About the configuration of lower case 1> As shown in FIG. 20, the lower case 1 may have a configuration in which a metal frame 14 is embedded inside a resin member. FIG. 20 is a conceptual diagram showing the internal structure of the lower case 1. Reference numeral 15 in FIG. 20 denotes resin that fills gaps in the metal frame 14. The metal frame 14 is preferably configured so as not to overlap portions that face the parallel polarization antenna 4x, such as the board parallel portion 42. In other words, the parallel polarization antenna 4x is preferably formed in an area of ​​the circuit board 3 that overlaps with the hole in the metal frame 14. Note that a portion of the parallel polarization antenna 4x may overlap the metal frame 14, as shown in FIG. 20.

[0115] <Number of antennas installed> Although the above describes a configuration including one parallel polarized antenna 4x, multiple parallel polarized antennas 4x may be provided. For example, as shown in Figures 21 and 22, multiple antennas 4 including substrate parallel portions 42 may be provided in a row. The configuration shown in Figure 21 corresponds to a configuration in which multiple (three) three-dimensional inverted-L antennas as antennas 4 are arranged in the X-axis direction at predetermined intervals to function as an array antenna. Furthermore, the configuration shown in Figure 22 corresponds to a configuration in which multiple (two) three-dimensional inverted-F antennas as antennas 4 are arranged in parallel in the X-axis direction.

[0116] A configuration in which multiple parallel polarized antennas 4x are arranged side by side allows them to function as an array antenna. It is preferable that the parallel polarized antenna 4x be configured so that radio waves travel in the direction of the window 210 when installed in a vehicle. In an array antenna, the directivity (beam) can be dynamically adjusted by adjusting the weighting coefficient for each antenna 4. Therefore, by setting the weighting coefficient for each antenna 4 based on the positional relationship between the installation target 200 and the window 210 and testing after or before installation in the vehicle, it is possible to adjust the directivity in the direction from the vehicular wireless device 100 toward the window 210. As a result, it is possible to increase the amount of radio waves that reach the back side of the installation target 200. The weighting coefficient is sometimes called a digital weight or an array factor. The weighting coefficient includes an amplitude coefficient that adjusts the amplitude and a phase coefficient that adjusts the phase. Various methods can be used to adjust the beam. While the above description concerns a configuration in which multiple parallel polarized antennas 4x are arranged, multiple vertically polarized antennas 5 may also be provided.

[0117] <Applicable vehicles> The vehicular wireless device 100 described above can be applied to a variety of vehicles traveling on roads. That is, the present disclosure can be installed in a variety of vehicles that can travel on roads, such as four-wheeled vehicles, two-wheeled vehicles, and three-wheeled vehicles. A motorized bicycle can also be considered a two-wheeled vehicle. A vehicle to which the system / device / method described herein can be applied may be a privately owned car or a service car. A service car refers to a vehicle used for a car-sharing service or a vehicle rental service, for example. Service cars include taxis, route buses, and shared buses. Service cars may also be driverless vehicles such as robot taxis or driverless buses. Service cars can broadly include vehicles that provide transportation services. Service cars can also include vehicles that function as unmanned delivery robots that automatically transport packages to a specified destination.

[0118] <Additional remarks> In the above embodiments, multiple functions of one component may be realized by multiple components, or one function of one component may be realized by multiple components. Furthermore, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. In addition, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0119] 100 Vehicle radio device, 200 Mounting target portion, 1 Lower case, 2 Upper case, 3 Circuit board, 32 Control circuit, 34 Support portion, 35 Ground pattern (ground portion), 35B Ground pattern (second board ground portion), 4 Antenna (parallel polarized wave antenna), 41 Standing portion, 42 Board parallel portion, 4x Parallel polarized wave antenna, 5 Vertical polarized wave antenna, 51 Opposing conductor plate, 52 Short circuit portion, BM Back conductor plate

Claims

1. a circuit board (3) made of a dielectric material and having mounted thereon a circuit (32) for transmitting or receiving radio waves at a predetermined target frequency of 700 MHz or more; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, A ground portion (35) which is a conductor plate that provides a ground potential for the circuit is not formed in an area of ​​the circuit board that overlaps with the board parallel portion, A marker (24) is provided on the side surface of the case, which is a line indicating the position of the substrate parallel portion within the case, At least a portion of the bottom surface of the case that faces the board parallel portion is made of resin, The vehicle radio device is mounted on a vehicle body with the parallel portion of the board spaced apart from the vehicle body by λ / 4 or more (λ is the wavelength of the radio wave).

2. a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, The bottom surface of the case is made of metal, The substrate parallel portion is disposed at a position electrically above the bottom surface (11) of the case by λ / 4 or more (λ is the wavelength of the radio wave), a conductive plate facing the board parallel portion is not disposed in a region within λ / 4 below the board parallel portion within a region inside the case that overlaps with the board parallel portion, a first substrate (3A) as the circuit board; and a second substrate (3B) that is a substrate different from the first substrate, A second substrate ground portion (35B) which is a conductive plate that provides a ground potential is formed on the lower surface or inside of the second substrate, The second board is disposed below the first board in a position facing the first board, with the board parallel portion and the second board ground portion electrically spaced apart by λ / 4 or more.

3. 3. The vehicular wireless device according to claim 2, In the circuit board, a ground portion (35) which is a conductive plate that provides a ground potential for the circuit is not formed in an area overlapping with the board parallel portion.

4. a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, The bottom surface of the case is made of metal, The substrate parallel portion is disposed at a position electrically above the bottom surface (11) of the case by λ / 4 or more (λ is the wavelength of the radio wave), a conductive plate facing the board parallel portion is not disposed in a region within λ / 4 below the board parallel portion within a region inside the case that overlaps with the board parallel portion, The circuit board includes a ground layer on which a ground portion (35) that is a conductive plate that provides a ground potential for the circuit is formed, The vehicle radio device is configured such that the parallel board portion is disposed relative to the circuit board such that the electrical separation between the ground layer and the parallel board portion is λ / 4 or more.

5. 5. The vehicular wireless device according to claim 1, The antenna has a three-dimensional shape in which an upright portion (41) stands upright from the circuit board and the board parallel portion is connected at the upper end of the upright portion.

6. a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, The bottom surface of the case is made of metal, The substrate parallel portion is disposed at a position electrically above the bottom surface (11) of the case by λ / 4 or more (λ is the wavelength of the radio wave), a conductive plate facing the board parallel portion is not disposed in a region within λ / 4 below the board parallel portion within a region inside the case that overlaps with the board parallel portion, The antenna has a three-dimensional shape in which an upright portion (41) stands upright from the circuit board and the board parallel portion is connected at the upper end of the upright portion.

7. A vehicle wireless device according to claim 6, In the circuit board, a ground portion (35) which is a conductive plate that provides a ground potential for the circuit is not formed in an area overlapping with the board parallel portion.

8. 8. The vehicular wireless device according to claim 5, The vehicle radio device, wherein the antenna is an inverted L-type antenna or an inverted F-type antenna.

9. 9. The vehicular wireless device according to claim 1, The board parallel portion is formed on the surface or inside of a support portion (34) made of resin and having a predetermined thickness, and is disposed on the upper side of the circuit board.

10. a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, The bottom surface of the case is made of metal, The substrate parallel portion is disposed at a position electrically above the bottom surface (11) of the case by λ / 4 or more (λ is the wavelength of the radio wave), a conductive plate facing the board parallel portion is not disposed in a region within λ / 4 below the board parallel portion within a region inside the case that overlaps with the board parallel portion, The board parallel portion is formed on the surface or inside of a support portion (34) made of resin and having a predetermined thickness, and is disposed on the upper side of the circuit board.

11. A vehicle wireless device according to claim 10, In the circuit board, a ground portion (35) which is a conductive plate that provides a ground potential for the circuit is not formed in an area overlapping with the board parallel portion.

12. 12. The vehicular wireless device according to claim 1, In addition to the parallel polarized antenna, A vehicle wireless device comprising a vertically polarized antenna (5) capable of receiving board vertically polarized waves, which are radio waves whose electric field vibration direction is perpendicular to the circuit board.

13. a circuit board (3) on which a circuit (32) for transmitting or receiving radio waves of a predetermined target frequency of 700 MHz or more is mounted; a parallel polarization antenna (4, 4x) for receiving the radio waves, which is configured to receive board-parallel polarized waves, which are radio waves whose vibration direction of the electric field is parallel to the circuit board, by having a board-parallel portion (42) that is a portion parallel to the circuit board; a case (1, 2) for accommodating the circuit board and the parallel polarized antenna; The circuit board is mounted in a position facing a predetermined mounting surface of a vehicle, The bottom surface of the case is made of metal, The substrate parallel portion is disposed at a position electrically above the bottom surface (11) of the case by λ / 4 or more (λ is the wavelength of the radio wave), a conductive plate facing the board parallel portion is not disposed in a region within λ / 4 below the board parallel portion within a region inside the case that overlaps with the board parallel portion, In addition to the parallel polarized antenna, A vehicle wireless device comprising a vertically polarized antenna (5) capable of receiving board vertically polarized waves, which are radio waves whose electric field vibration direction is perpendicular to the circuit board.

14. A vehicle radio device according to claim 13, In the circuit board, a ground portion (35) which is a conductive plate that provides a ground potential for the circuit is not formed in an area overlapping with the board parallel portion.

15. 15. The vehicular wireless device according to claim 12, A ground portion (35) which is a conductive plate that provides a ground potential for the circuit is formed on the lower surface or inside of the circuit board, The vertically polarized antenna is an opposing conductor plate (51) which is a flat conductor member provided at a predetermined distance from the ground portion and has a power supply point; a short-circuiting portion (52) provided in a central region of the opposing conductor plate and electrically connecting the opposing conductor plate and the ground portion, The vehicle radio device is configured to resonate in parallel at the target frequency using an inductance provided in the short-circuit portion and a capacitance formed by the ground portion and the opposing conductor plate.

16. 16. A vehicular wireless device according to any one of claims 1 to 15, a plurality of the parallel polarized antennas; The plurality of parallel polarized antennas are arranged in a predetermined direction in the vehicle radio apparatus.

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