Antenna device and radar device

Abstract

To provide an antenna device capable of restricting unwanted radiation from an antenna connection part.SOLUTION: A first antenna and a second antenna are connected to an antenna connection part 62, the antenna connection part 62 is connected to an eighth side conversion part 60. The eighth side conversion part 60 converts a signal transferred among a waveguide, the first antenna, and the second antenna. A dielectric layer is provided on a side surface of the antenna connection part 62, and a plurality of via holes 48 are formed in the dielectric layer along the periphery of the antenna connection part 62.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an antenna device and a radar device. [Background technology]

[0002] For example, Patent Document 1 listed below describes an antenna device to which a pair of microstrip antennas are connected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6365494 Summary of the Invention [Problem to be solved by the invention]

[0004] When a pair of microstrip antennas is connected as described above, there is a risk that unwanted radiation from the connection portion will cause the antenna directivity to deviate from the intended one. [Means for solving the problem]

[0005] In order to solve the above problems, the antenna device comprises a conductor layer A (L8), a conductor layer B (L7), and a dielectric layer (P7) sandwiched between the conductor layer A and the conductor layer B, and a first antenna (66a), a second antenna (66b), and connecting conductors (60, 62, 64) connected to both the first antenna and the second antenna are formed on the conductor layer A, and a guard conductor (48) is provided on the dielectric layer, and the guard conductor is arranged along the outer periphery of the connecting conductor, excluding at least a first connection point which is a connection point with the first antenna, and a second connection point which is a connection point with the second antenna.

[0006] According to the above configuration, the A conductor layer, the B conductor layer, and the guard conductor can form an internal waveguide within the substrate for propagating signals between the antenna connection portion and the first antenna and second antenna, thereby suppressing unwanted radiation from the antenna connection portion. [Brief description of the drawings]

[0007] [Figure 1] 1 is an exploded perspective view showing a configuration of a radar device according to an embodiment; [Diagram 2] FIG. 2 is a diagram illustrating an example of the arrangement of a radar device according to the embodiment. [Diagram 3] FIG. 2 is a cross-sectional view showing a cross-sectional configuration of the antenna device according to the embodiment. [Figure 4] FIG. 2 is an exploded perspective view showing the configuration of the antenna device according to the embodiment. [Diagram 5] 6A and 6B are diagrams showing members connected to a first conversion part in the embodiment. [Figure 6] FIG. 13 is a plan view showing an eighth side conversion unit, an antenna connection unit, and an antenna in the embodiment. [Figure 7] 13 is a perspective view showing the arrangement of vias connected to an eighth side conversion section and an antenna connection section in the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of a radar device will be described with reference to the drawings. 1 shows the configuration of a radar device 10 according to this embodiment. The radar device 10 is a device in which an antenna device 18 is accommodated in a space defined by a radome 12 and a lower case 20, and a connector 22 is attached to the lower case 20.

[0009] Fig. 2 shows an example of the arrangement of the radar devices 10. Fig. 2 shows an example in which one radar device 10 is arranged in the center of the front of the vehicle VC, and one each on the left and right sides of the rear. FIG. 3 shows a cross-sectional configuration of the antenna device 18. The antenna device 18 is a substrate in which a first conductor layer L1, a first dielectric layer P1, a second conductor layer L2, a second dielectric layer P2, a third conductor layer L3, a third dielectric layer P3, a fourth conductor layer L4, a fourth dielectric layer P4, a fifth conductor layer L5, a fifth dielectric layer P5, a sixth conductor layer L6, a sixth dielectric layer P6, a seventh conductor layer L7, a seventh dielectric layer P7, and an eighth conductor layer L8 are sequentially laminated. As shown in FIG. 3, the lamination direction is hereinafter referred to as the z direction. In particular, the direction proceeding from the first conductor layer L1 to the eighth conductor layer L8 is referred to as the positive z direction.

[0010] For the sake of convenience, the antenna device 18 will be hereinafter classified into a first outer layer portion 30, an inner layer portion 32, and a second outer layer portion 34. The first outer layer portion 30 includes a first conductor layer L1, a first dielectric layer P1, a second conductor layer L2, and a second dielectric layer P2. The inner layer portion 32 includes a third conductor layer L3, a third dielectric layer P3, a fourth conductor layer L4, a fourth dielectric layer P4, a fifth conductor layer L5, a fifth dielectric layer P5, and a sixth conductor layer L6. The second outer layer portion 34 includes a sixth dielectric layer P6, a seventh conductor layer L7, a seventh dielectric layer P7, and an eighth conductor layer L8.

[0011] A waveguide 36 is provided in the inner layer portion 32 so as to penetrate the inner layer portion 32. The third conductor layer L3, the fourth conductor layer L4, the fifth conductor layer L5, and the sixth conductor layer L6 constituting the inner layer portion 32 are all grounded and form a ground plane.

[0012] FIG. 4 shows an exploded perspective view of the antenna device 18. As shown in FIG. As shown in FIG. 4, the first conductor layer L1 is formed with a microstrip line 52 and a first side conversion section 50 that converts a signal transmitted from either the waveguide 36 or the microstrip line 52 to the other.

[0013] As shown in FIG. 5, a monolithic microwave integrated circuit (MMIC 54 ) is connected to the first side conversion section 50 via a microstrip line 52 . The MMIC 54 according to this embodiment includes two-channel terminals for transmission and three-channel terminals for reception. Therefore, in reality, a separate first-side converter 50 is formed for each of these channels on the first conductor layer L1. The first-side converter 50 for transmission is a member for converting a high-frequency signal from the MMIC 54 into an electromagnetic wave and outputting the electromagnetic wave to the waveguide 36. The first-side converter 50 for reception is a member for converting an electromagnetic wave from the waveguide 36 into a high-frequency signal that is output to the microstrip line 52.

[0014] The MMIC 54 executes a transmission process of generating a high frequency signal of 76 to 77 GHz and transmitting it to the microstrip line 52, and a reception process of receiving a high frequency signal of 76 to 77 GHz input via the microstrip line 52. The MMIC 54 also includes a mixer and the like that combines the high frequency signal transmitted by the transmission process and the high frequency signal received by the reception process.

[0015] The waveguide 36 is made of metal and has a tubular structure. A pair of ends in the z direction, which is the axial direction of the waveguide 36, are connected to the third conductor layer L3 and the sixth conductor layer L6, respectively. In this embodiment, the signal to be transmitted by the waveguide 36 is a signal of a single fundamental mode of the TE mode. This is because signal processing is easier than when signals of multiple modes are transmitted. Specifically, a waveguide equivalent to a rectangular waveguide is adopted as the waveguide 36, and a signal of the fundamental mode of the TE mode, which is a single mode, is a cutoff frequency of each mode that is lower than the frequency band of 76 to 77 GHz. The waveguide 36 of this embodiment is equivalent to a rectangular wave waveguide, and it is presumed that the TE mode is defined so as to satisfy the boundary condition that the electric field is zero at both ends in the longitudinal direction.

[0016] The MMIC 54 is connected to a microcomputer (microcomputer 56). The microcomputer 56 includes a CPU 56a and a memory 56b, and the CPU 56a executes a program stored in the memory 56b. The processes executed by the CPU 56a include a process for controlling the transmission process and reception process of the high-frequency signal by the MMIC 54. The processes executed by the CPU 56a also include a process for calculating the relative distance and relative speed between the radar device 10 and an object that reflects the high-frequency signal transmitted from the radar device 10 based on the signal mixed by the mixer, and a process for transmitting the calculation result to the outside of the radar device 10 via the connector 22.

[0017] Returning to FIG. 4, the eighth conductor layer L8 is provided with an antenna 66 and an eighth-side converter 60 that converts a signal transmitted from either the antenna 66 or the waveguide 36 to the other.

[0018] As shown in Fig. 3 and Fig. 4, the second conductor layer L2 is formed with a second side slit 38. Also, the second dielectric layer P2 is provided with a via 42. More specifically, a vertical projection of the via 42 onto a plane that includes the second conductor layer L2 and is perpendicular to the z direction results in a figure that surrounds the second side slit 38. Each of the multiple vias 42 extends in the z direction to connect the second conductor layer L2 and the third conductor layer L3. As a result, the second conductor layer L2 is also grounded, forming a ground plane.

[0019] Also, the first dielectric layer P1 is formed with vias 44. More specifically, the figure obtained by vertically projecting the vias 44 onto a plane including the first conductor layer L1 and perpendicular to the z direction is formed along the outer periphery of the first side conversion unit 50 except for the vicinity of the connection with the microstrip line 52. Also, the figure obtained by vertically projecting the vias 44 onto a plane including the first conductor layer L1 and perpendicular to the z direction is a figure that surrounds the figure obtained by vertically projecting the second side slit 38 onto the same plane except for the vicinity of the connection. This is a setting for reducing the transmission loss of signals between the microstrip line 52 and the first side conversion unit 50. The multiple vias 44 each connect the second conductor layer L2 and the first conductor layer L1 by extending in the z direction.

[0020] A seventh side slit 40 is formed in the seventh conductor layer L7. Also, a via 46 is provided in the sixth dielectric layer P6. More specifically, a vertical projection of the via 46 onto a plane including the seventh conductor layer L7 and perpendicular to the z direction results in a figure surrounding the seventh side slit 40. Each of the vias 46 extends in the z direction to connect the seventh conductor layer L7 and the sixth conductor layer L6. As a result, the seventh conductor layer L7 is also grounded, forming a ground plane.

[0021] Furthermore, the seventh dielectric layer P7 is provided with a via 48. The via 48 extends in the z-direction to connect the seventh conductor layer L7 and the eighth conductor layer L8. FIG. 6 shows a part of the eighth conductor layer L8.

[0022] The dashed line shown in Fig. 6 is a figure obtained by vertically projecting the waveguide 36 onto a plane including the eighth conductor layer L8 and perpendicular to the z direction. As shown in Fig. 6, this figure is included in the eighth-side conversion section 60. This figure almost overlaps with a figure obtained by vertically projecting the seventh-side slit 40 onto a plane including the eighth conductor layer L8 and perpendicular to the z direction. This figure is also surrounded by a figure obtained by vertically projecting the via 46 onto a plane including the eighth conductor layer L8 and perpendicular to the z direction.

[0023] The eighth-side converter 60 is connected to an antenna connection section 62 whose length in the y direction gradually increases. The antenna connection section 62 is connected to an antenna 66 via an impedance conversion circuit 64. More specifically, a first antenna 66a and a second antenna 66b are connected via each of the pair of impedance conversion circuits 64. Here, the impedance conversion circuit 64 has a length Ln2 in the y direction at the connection point with the antenna 66 that is shorter than a length Ln1 in the y direction at the connection point with the antenna connection section 62. The impedance conversion circuit 64 has a shape in which the length in the y direction gradually decreases as it proceeds from the antenna connection section 62 to the antenna 66. This is a setting for suppressing a sudden change in impedance in a path from one of the antenna connection section 62 and the first antenna 66a and the second antenna 66b to the other.

[0024] The first antenna 66a and the second antenna 66b are laid out along the x direction. In Fig. 6, the direction in which the first antenna 66a and the second antenna 66b extend is defined as the positive x direction.

[0025] Of the ends of the antenna connection portion 62 in the positive x direction, side protrusions 63a are provided at both ends in the y direction to sandwich a pair of impedance conversion circuits 64. The side protrusions 63a are rectangular conductors that protrude from the antenna connection portion 62 in the positive x direction.

[0026] An intermediate protrusion 63b is provided between the connection points of the ends of the antenna connecting portion 62 in the positive x direction and the pair of impedance converting circuits 64. The intermediate protrusion 63b is a rectangular conductor that protrudes in the positive x direction from the antenna connecting portion 62.

[0027] FIG. 7 shows the eighth converter 60, the antenna connection portion 62, the impedance conversion circuit 64, the side protrusion 63a, and the intermediate protrusion 63b as viewed from the negative z direction. As shown in Fig. 7, the vias 48 include a plurality of side vias 48a formed in a row along the outer periphery of each of both ends in the y direction of the eighth side conversion section 60 and the antenna connection section 62. The side vias 48a include those connected to the side protrusion section 63a. In other words, the side vias 48a include those arranged at positions along the side protrusion section 63a. Specifically, the shapes of the side vias 48a vertically projected onto a plane including the eighth conductor layer L8 and perpendicular to the z direction are included in the eighth side conversion section 60, the antenna connection section 62, and the side protrusion section 63a.

[0028] The via 48 has a plurality of back-side vias 48b formed in a row along the outer periphery on the end side in the negative x direction of the eighth side conversion section 60. Specifically, the figures of the back-side vias 48b vertically projected onto a plane that includes the eighth conductor layer L8 and is perpendicular to the z direction are included in the eighth side conversion section 60.

[0029] The vias 48 also include a plurality of inter-vias 48c formed in a row along the x direction in the center of the antenna connection portion 62 in the y direction. The inter-vias 48c also include one connected to the inter-protrusion portion 63b. In other words, the inter-vias 48c include one arranged at a position along the inter-protrusion portion 63b. Specifically, the figures of the inter-vias 48c vertically projected onto a plane that includes the eighth conductor layer L8 and is perpendicular to the z direction are encompassed by the antenna connection portion 62 and the inter-protrusion portion 63b.

[0030] Furthermore, with this configuration, the vertical projection of the waveguide 36 onto a plane that includes the eighth conductor layer L8 and is perpendicular to the z-direction is surrounded by the vertical projection of the via 48 onto the same plane, except for the vicinity of a pair of impedance conversion circuits 64.

[0031] Here, the operation and effects of this embodiment will be described. The first antenna 66a and the second antenna 66b are connected to the eighth-side conversion section 60 via the antenna connection section 62, and the side vias 48a are connected along the outer periphery of each of the two ends in the y direction of the antenna connection section 62. As a result, an in-substrate waveguide is formed by the seventh conductor layer L7, the eighth conductor layer L8, and the side vias 48a. Therefore, compared to a case where the side vias 48a are not provided, it is possible to suppress unnecessary radiation from the antenna connection section 62, and thus to suppress distortion of the directivity achieved by the first antenna 66a and the second antenna 66b from the intended one.

[0032] According to the present embodiment described above, the following actions and effects can be obtained. (1) The via hole 48c is connected to the antenna connection portion 62. This makes it possible to form, in the waveguide within the substrate, a distributor that distributes signals from the eighth side conversion portion 60 to the first antenna 66a and the second antenna 66b, and a coupler that combines signals from the first antenna 66a and the second antenna 66b to the eighth side conversion portion 60. Therefore, unnecessary radiation from the antenna connection portion 62 can be suppressed.

[0033] (2) The eighth-side conversion unit 60 is connected to the antenna connection unit 62, and the eighth-side conversion unit 60 converts the signal exchanged between the waveguide 36 and the antenna connection unit 62. In this case, a distributor or coupler formed between the eighth-side conversion unit 60 and the first and second antennas 66a and 66b can be configured with a simple design using an in-substrate waveguide formed by the antenna connection unit 62 and the vias 48. Furthermore, the in-substrate waveguide can propagate a signal in the same mode as the signal propagated through the waveguide 36, so that signal transmission loss can be easily reduced compared to, for example, transmitting a signal from the MMIC 54 to the eighth conductor layer L8 through a coaxial line.

[0034] (3) The first antenna 66a and the second antenna 66b are connected to the antenna connection unit 62 via the impedance conversion circuit 64. This makes it possible to prevent a sudden change in impedance when a signal is transmitted from either the antenna connection unit 62 or the first antenna 66a or the second antenna 66b to the other.

[0035] (4) The side protrusion 63a is connected to the seventh conductor layer L7 by the via 48. This makes it possible to prevent unwanted radio waves from being emitted through the impedance conversion circuit 64.

[0036] (5) The projection 63b is connected to the seventh conductor layer L7 by the via 48. This makes it possible to prevent unwanted radio waves from being emitted through the impedance conversion circuit 64. <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0037] "About the side protrusions" The length of the side protrusion 63a extending in the x direction is not necessarily shorter than the length of the impedance conversion circuit 64 in the x direction. For example, the length may be equal to the length of the impedance conversion circuit 64 in the x direction, or may be longer than the length of the impedance conversion circuit 64 in the x direction.

[0038] Incidentally, the provision of the side protrusion 63a does not presuppose the provision of the impedance conversion circuit 64. In other words, even if the impedance conversion circuit 64 is not provided, the provision of the side protrusions 63a so as to sandwich the connection points between the antenna connection portion 62 and the first antenna 66a and the second antenna 66b is effective in suppressing electric field leakage.

[0039] "About the protrusions" The length of the inter-protrusion portion 63b extending in the x direction is not necessarily shorter than the length of the impedance conversion circuit 64 in the x direction; for example, it may be equal to the length of the impedance conversion circuit 64 in the x direction, or it may be longer than the length of the impedance conversion circuit 64 in the x direction.

[0040] Incidentally, the provision of the intermediate protrusion 63b does not presuppose the provision of the impedance conversion circuit 64. In other words, even if the impedance conversion circuit 64 is not provided, the provision of the intermediate protrusion 63b between the connection points of the antenna connection portion 62 and the first antenna 66a and the second antenna 66b is effective in suppressing electric field leakage.

[0041] "Number of antennas connected to antenna connector" The number of antennas connected to the antenna connection portion 62 is not limited to two, the first antenna 66a and the second antenna 66b, but may be three or more. Furthermore, each antenna may have a different shape and radiation directivity. Note that it is not essential that all of the multiple antenna connection portions 62 formed in the antenna device 18 are connected to multiple antennas, and an antenna connection portion connected to only one antenna may be included.

[0042] "About connecting conductors" It is not essential to provide an impedance conversion circuit 64 between the antenna connection portion 62 and the first antenna 66a or the second antenna 66b, which gradually changes the impedance from one of a pair of impedances, that is, the impedance of the antenna connection portion 62 and the impedance of the first antenna 66a or the second antenna 66b, to the other value.

[0043] It is not essential to form the antenna connection part 62 by expanding the length in the y direction with respect to the eighth conversion part 60. For example, the eighth conversion part 60 and the antenna connection part 62 may have the same length in the y direction. In this case, it is not essential to separate the eighth conversion part 60 and the antenna connection part 62, for example, in cases where the intermediate via 48c is not provided as described in the "Guard Conductor" section. For example, the eighth conversion part 60 and the antenna connection part 62 may be integrated and inseparable by making the shape of the waveguide 36 projected in the positive direction of the z axis approximately centered at both ends of the eighth conversion part 60 and the antenna connection part 62 in the x axis direction.

[0044] As described in the section "Regarding Waveguides" below, even if the extension direction of the waveguide, which is the axial direction of the waveguide, deviates from the z direction, it is desirable that the figure of the waveguide 36 projected onto a plane perpendicular to the z direction and including the eighth conductor layer L8 by a light ray parallel to the axial direction be included in the eighth side conversion section 60.

[0045] The side protrusions 63a are not essential. It is not essential to provide the intermediate protrusion 63b. "About guard conductors" In the above embodiment, all of the side vias 48a are arranged so that the figure projected perpendicularly onto a plane perpendicular to the z direction and including the eighth conductor layer L8 is included in the eighth conversion section, the antenna connection section 62, and the side protrusion section 63a, but this is not limited thereto. For example, the side vias 48a may be arranged so that a part of the figure projected perpendicularly onto the plane extends beyond the y-direction end of the eighth conversion section, the antenna connection section 62, or the side protrusion section 63a.

[0046] In the above embodiment, the side vias 48a are arranged in one row at each of the eighth conversion section and both ends of the antenna connection section 62 in the y direction, but this is not limited thereto. For example, multiple rows, such as two rows, may be arranged. In this case, for example, the positions of the side vias 48a in the x direction may be different between the first row and the second row. In addition, the portion of the side vias 48a projected onto the side protrusion section 63a in the figure obtained by vertically projecting the side vias 48a onto a plane perpendicular to the z direction and including the eighth conductor layer L8 may also be arranged in multiple rows.

[0047] In such a case, for example, the figure of the first row side via 48a projected vertically onto a plane orthogonal to the z-axis and including the eighth conductor layer L8 may not overlap with any of the eighth side conversion part 60, the antenna connection part 62, and the side protrusion part 63a. In that case, however, it is preferable that the figure of the second row side via 48a projected vertically onto the same plane is included in the eighth side conversion part, the antenna connection part 62, and the side protrusion part 63a.

[0048] It is not essential that the vertical projection of the side via 48a onto a plane perpendicular to the z-direction and including the eighth conductor layer L8 overlaps with the eighth conversion section, the antenna connection section 62, and the side protrusion section 63a. For example, the vertical projection of the side via 48a onto the same plane may be disposed adjacent to the antenna connection section 62, etc.

[0049] In the above embodiment, all of the back side vias 48b are arranged so that the figure obtained by vertically projecting one of the back side vias 48b onto a plane orthogonal to the z direction and including the eighth conductor layer L8 is included in the eighth side conversion part, but this is not limited to the above. For example, the back side vias 48b may be arranged so that a part of the figure obtained by vertically projecting one of the back side vias 48b onto the same plane extends beyond the end of the eighth side conversion part in the x direction.

[0050] In the above embodiment, the multiple back side vias 48b are arranged in one row at the end of the eighth side conversion section 60 in the x direction, but this is not limited to this. For example, multiple rows, such as two rows, may be arranged. In this case, for example, the positions of the back side vias 48b in the y direction may be different between the first row and the second row.

[0051] In such a case, for example, for the back side vias 48b in the first row, a figure vertically projected onto a plane orthogonal to the z direction and including the eighth conductor layer L8 may not have a portion overlapping with the eighth side conversion section 60. However, in that case, for the back side vias 48b in the second row, a figure vertically projected onto the same plane is desirably included in the eighth side conversion section 60.

[0052] It is not essential that the vertical projection of the back-side via 48b onto a plane perpendicular to the z-direction and including the eighth conductor layer L8 overlaps with the eighth-side conversion unit 60. For example, the vertical projection of the back-side via 48b onto the same plane may be disposed adjacent to the eighth-side conversion unit 60.

[0053] In the above embodiment, all of the intermediate vias 48c are arranged such that the figure, which is projected perpendicularly onto a plane that is perpendicular to the z direction and includes the eighth conductor layer L8, is encompassed by the antenna connection portion 62 and the intermediate protrusion 63b, but this is not limited thereto. For example, one of the intermediate vias 48c may be arranged such that a part of the figure, which is projected perpendicularly onto a plane that is perpendicular to the z direction and includes the eighth conductor layer L8, protrudes from the end of the intermediate protrusion 63b in the x direction.

[0054] In the above embodiment, the multiple intermediate vias 48c are arranged in one row along a line parallel to the x direction, but this is not limited to the above. For example, multiple rows, such as two rows, may be arranged. In this case, for example, the positions of the intermediate vias 48c in the y direction may be different between the first row and the second row.

[0055] It is not essential to provide the side via 48a, the back side via 48b, and the intermediate via 48c as the guard conductor. For example, the configuration may include the side via 48a and the back side via 48b, but not the intermediate via 48c. In this case, it is desirable to form a slit in the antenna connection portion 62 at the location where the intermediate via 48c was located. Also, for example, the configuration may include the intermediate via 48c, but not the side via 48a.

[0056] The guard conductor is not limited to being composed of a plurality of vias. For example, the portion of the guard conductor consisting of the plurality of side vias 48a and the plurality of back side vias 48b may be composed of a single U-shaped conductor.

[0057] It is not essential that the guard conductor is connected to the eighth conversion unit 60, the antenna connection unit 62, the side protrusions 63a, and the inter-protrusions 63b. For example, a dielectric layer may be interposed between the guard conductor and the eighth conversion unit 60, the antenna connection unit 62, the side protrusions 63a, and the inter-protrusions 63b.

[0058] It is not essential that the guard conductor is connected to the seventh conductor layer L7. For example, a dielectric layer may be interposed between the guard conductor and the seventh conductor layer. "About antenna devices" For example, the fifth conductor layer L5 may be deleted from the inner layer portion 32, and the inner layer portion 32 may be configured with three conductor layers and two dielectric layers. Also, for example, the fourth conductor layer L4 and the fifth conductor layer L5 may be deleted from the inner layer portion 32, and the inner layer portion 32 may be configured with two conductor layers and one dielectric layer. Furthermore, for example, the third conductor layer L3, the fourth conductor layer L4, the fifth conductor layer L5, and the sixth conductor layer L6 may be deleted from the inner layer portion 32, and the waveguide 36 may be embedded in the dielectric layers.

[0059] The second conductor layer L2 may be omitted from the first outer layer portion 30, and the first outer layer portion 30 may be configured with one conductor layer and one dielectric layer. The seventh conductor layer L7 may be omitted from the second outer layer portion 34, and the second outer layer portion 34 may be configured with one conductor layer and one dielectric layer.

[0060] It is not essential that the inside of the waveguide 36 is filled with a dielectric. It is not essential that the microstrip line 52 connecting the first conversion unit 50 and the MMIC 54 is formed on the first conductor layer L1. For example, the MMIC 54 may be directly connected to the first conversion unit 50.

[0061] The transmission path for transmitting a signal along the z direction is not limited to the waveguide 36 . The MMIC 54 is not limited to a configuration in which it is connected only to the first conductor layer L1. For example, the transmitting MMIC 54 may be connected to the first conductor layer L1, while the receiving MMIC 54 may be connected to the eighth conductor layer L8. In other words, by connecting the receiving MMIC 54 to the antenna connection portion 62, a signal received by the first antenna 66a or the second antenna 66b may be transmitted to the MMIC 54 without passing through the waveguide 36.

[0062] The MMIC 54 does not have to be connected to the first conductor layer L1. That is, the MMIC 54 that performs transmission and reception processes may be directly connected to the antenna connection section 62. In that case, the first outer layer section 30 and the inner layer section 32 do not have to be provided.

[0063] "About Waveguides" In the above embodiment, a waveguide in which the high-frequency signal to be transmitted is in only the fundamental mode of the TE mode has been described as an example, but the present invention is not limited to this.

[0064] The cross-sectional shape of the waveguide is not limited to that exemplified in the above embodiment. For example, the waveguide may have a shape in which the length in the short direction is longer at both ends in the long direction than at the center. In the above embodiment, the transmitting waveguide and the receiving waveguide are separate, but the present invention is not limited to this.

[0065] The extension direction of the waveguide, which is the axial direction of the waveguide, is not necessarily parallel to the z direction, which is the lamination direction, and there may be a misalignment between these two directions. "About the processing circuit" In the above embodiment, the MMIC 54 has a plurality of channels, but this is not limiting. For example, one MMIC may be provided for each of a plurality of channels.

[0066] In the above embodiment, the MMIC 54 and the microcomputer 56 that controls the transmission and reception processing by the MMIC 54 and analyzes the signal output by the MMIC 54 are separate components, but they may be integrated.

[0067] "About radar equipment" The number of transmitting antennas and the number of receiving antennas are not limited to those exemplified in the above embodiment. For example, in cases where phased array processing is not performed, only one transmitting antenna may be provided.

[0068] The MMIC 54 and the microcomputer 56 are not limited to being mounted on a single antenna device 18. For example, the MMIC 54 and the microcomputer 56 may be mounted on separate boards.

[0069] The output signal of the radar device is not limited to a signal indicating the detection result of the relative speed and distance between the vehicle and an object outside the vehicle. For example, the output signal may be a signal used for calculating the relative speed and distance between the vehicle and an object outside the vehicle from outside the radar device.

[0070] The radar device for vehicles is not limited to a device that transmits and receives radar at 76 to 77 GHz. For example, it may be a device that transmits and receives radar at 76 to 80 GHz, or a device that transmits and receives radar in the 24 GHz band. However, it is not limited to a device that transmits and receives millimeter wave radar.

[0071] "Others" The material of the dielectric layer is not limited to the one exemplified in the above embodiment. The material of the conductor layer is not limited to the one exemplified in the above embodiment. [Explanation of symbols]

[0072] 10. Radar equipment 18...Antenna device 48…Beer 60…8th side conversion part 62…Antenna connection 63a…Side protrusion 63b…Protrusion between 64…Impedance conversion circuit 66a…First antenna 66b…Second antenna

Claims

1. A conductive layer (L8); A second conductive layer (L7); A dielectric layer (P7) sandwiched between the first conductor layer and the second conductor layer, The conductor layer is formed with a first antenna (66a), a second antenna (66b), and connecting conductors (60, 62, 64) connected to both the first antenna and the second antenna, The dielectric layer is provided with a guard conductor (48), the guard conductor is disposed along an outer periphery of the connecting conductor, excluding at least a first connection portion which is a connection portion of the connecting conductor with the first antenna and a second connection portion which is a connection portion of the connecting conductor with the second antenna, The guard conductor (48c) is arranged in parallel to the direction in which the first antenna and the second antenna are installed and at a position sandwiched between the first connection point and the second connection point in the antenna device (18).

2. A conductive layer (L8); A second conductive layer (L7); A dielectric layer (P7) sandwiched between the first conductor layer and the second conductor layer, The conductor layer is formed with a first antenna (66a), a second antenna (66b), and connecting conductors (60, 62, 64) connected to both the first antenna and the second antenna, The dielectric layer is provided with a guard conductor (48), the guard conductor is disposed along an outer periphery of the connecting conductor, excluding at least a first connection portion which is a connection portion of the connecting conductor with the first antenna and a second connection portion which is a connection portion of the connecting conductor with the second antenna, the connection conductor includes side protrusions (63 a) protruding in a direction in which the first antenna and the second antenna are laid, the side protrusions (63 a) sandwiching the two connection points, i.e., the first connection point and the second connection point; The antenna device (18) has a guard conductor also disposed at a position along the side protrusion.

3. A conductive layer (L8); A second conductive layer (L7); A dielectric layer (P7) sandwiched between the first conductor layer and the second conductor layer, The conductor layer is formed with a first antenna (66a), a second antenna (66b), and connecting conductors (60, 62, 64) connected to both the first antenna and the second antenna, The dielectric layer is provided with a guard conductor (48), the guard conductor is disposed along an outer periphery of the connecting conductor, excluding at least a first connection portion which is a connection portion of the connecting conductor with the first antenna and a second connection portion which is a connection portion of the connecting conductor with the second antenna, the connection conductor includes a projection (63b) that is sandwiched between two connection points, the first connection point and the second connection point, and that projects in a direction in which the first antenna and the second antenna are laid; The antenna device (18) has a guard conductor also disposed along the intermediate protrusion.

4. A conductive layer (L8); A second conductive layer (L7); A dielectric layer (P7) sandwiched between the first conductor layer and the second conductor layer, The conductor layer is formed with a first antenna (66a), a second antenna (66b), and connecting conductors (60, 62, 64) connected to both the first antenna and the second antenna, The dielectric layer is provided with a guard conductor (48), A waveguide (36) is provided for the connection conductor in a direction from the first conductor layer to the second conductor layer, a figure obtained by projecting the waveguide by a light ray parallel to the axial direction of the waveguide onto a plane perpendicular to the lamination direction of the B conductor layer, the dielectric layer, and the A conductor layer and including the A conductor layer is included in the connecting conductor; The first antenna and the second antenna are configured to extend in the same direction, The antenna device (18) is arranged along the outer periphery of the connecting conductor in the direction in which the first antenna and the second antenna extend, excluding at least a first connection point of the connecting conductor which is a connection point with the first antenna and a second connection point of the connecting conductor which is a connection point with the second antenna, further than the area containing the figure.

5. A waveguide (36) is provided for the connection conductor in a direction from the first conductor layer to the second conductor layer, The antenna device according to any one of claims 1 to 4, wherein a projection of the waveguide by a light ray parallel to the axial direction of the waveguide onto a plane perpendicular to the stacking direction of the B conductor layer, the dielectric layer, and the A conductor layer and including the A conductor layer is contained in the connecting conductor and is surrounded by a vertical projection of the guard conductor onto the plane, excluding at least the first connection point side and the second connection point side.

6. The antenna device according to any one of claims 1 to 5, wherein the first connection point has a portion (64) whose length in a direction perpendicular to the installation direction of the first antenna becomes shorter as it progresses toward the extension direction of the first antenna within the installation direction.

7. 7. The antenna device according to claim 1, wherein the guard conductor is formed of a plurality of vias.

8. An antenna device according to any one of claims 1 to 7; a processing circuit (54, 56) that executes at least one of two processes, a transmission process and a reception process of a high frequency signal using the first antenna and the second antenna.

9. the antenna device includes a C conductor layer in a direction from the A conductor layer to the B conductor layer, 9. The radar device (10) according to claim 8, wherein the processing circuitry is connected to the third conductor layer (L1).

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