JP2011182082A - Substrate structure and radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for preventing leakage of an electromagnetic wave to be transmitted in a waveguide to be formed by joining a plurality of substrates from a substrate joining surface. <P>SOLUTION: In the electromagnetic wave whose frequency changes in time between an upper limit frequency and a lower limit frequency, a choke groove having a depth corresponding to a predetermined position from the waveguide is provided at a position corresponding to the wavelength of a frequency to be selected from a range from the upper limit frequency to the lower limit frequency. In addition, a choke groove having a depth corresponding to the predetermined position from the waveguide is provided at a position corresponding to the wavelength of a frequency different from the frequency to be selected from the range from the upper limit frequency to the lower limit frequency. Thus, the leakage of the electromagnetic wave from the joining surface of the plurality of substrates is prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for preventing leakage of electromagnetic waves.

  Generally, when an electromagnetic wave generated by a high-frequency circuit provided in a radar device is transmitted from an antenna as a transmission wave, or when the transmission wave is reflected from an object and received from an antenna as a reception wave, and transmitted to a high-frequency circuit, It passes through waveguides provided on substrates such as dielectric substrates and metal plates. Thus, the waveguide serving as an electromagnetic wave transmission path is formed by bonding substrates together. Then, due to the warpage of the substrates to be bonded and the unevenness of the bonding surfaces, when electromagnetic waves are transmitted through the waveguide, there is a problem that the electromagnetic waves leak from the gaps between the bonding surfaces where the plurality of substrates are bonded.

  On the other hand, the free space wavelength of the electromagnetic wave transmitted using the waveguide is λ, and a depth of λ / 4 is formed in a part of the portion along the opening edge of the waveguide and λ / 4 away from the opening edge. A technique for providing a choke groove having a thickness is disclosed. (For example, Patent Document 1)

JP 2009-200591 A

  However, in the technique of Patent Document 1, a specific frequency can be electrically short-circuited to prevent leakage of electromagnetic waves. However, in the case of an electromagnetic wave whose frequency changes with time, a substrate bonding surface having a frequency other than the specific frequency. Electromagnetic leakage from the gap cannot be electrically short-circuited. Therefore, in the case of electromagnetic waves whose frequency changes with time, there has been a problem that leakage of electromagnetic waves from the gap between the substrate bonding surfaces cannot be sufficiently prevented.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of preventing leakage of electromagnetic waves transmitted through a waveguide formed by bonding a plurality of substrates from a substrate bonding surface. To do.

  In order to solve the above-mentioned problem, the invention of claim 1 is a substrate structure in which a plurality of substrates are joined so as to communicate a waveguide that transmits an electromagnetic wave whose frequency changes temporally between an upper limit frequency and a lower limit frequency. The wavelength of the electromagnetic wave of the first frequency selected from the range from the upper limit frequency to the lower limit frequency is λa; different from the first frequency selected from the range from the upper limit frequency to the lower limit frequency When the wavelength of the electromagnetic wave of the second frequency is λb, each of the substrates to be bonded to each other is provided at a position approximately λa / 4 away from the waveguide on the bonding surface side with the other substrate, The first choke groove having a depth of approximately λa / 4 and the other substrate are provided at a position approximately λb / 4 away from the waveguide on the joint surface side with the one substrate, and approximately λb / 4 depth And a second choke groove.

  According to a second aspect of the present invention, in the substrate structure according to the first aspect, each of the plurality of waveguides that communicate with the plurality of substrates and extend in parallel with each other includes the first choke groove and the first chord groove. The two choke grooves are provided on the side where other adjacent waveguides exist with respect to each of the plurality of waveguides.

  According to a third aspect of the present invention, in the substrate structure according to the first or second aspect, the first frequency is the lower limit frequency, and the second frequency is the upper limit frequency.

  Further, the invention of claim 4 is a substrate body having the substrate structure according to any one of claims 1 to 3, and an electromagnetic wave provided on the substrate body, the frequency of which varies with time between an upper limit frequency and a lower limit frequency. And a high-frequency circuit for generating.

  According to invention of Claim 1 thru | or 4, the 1st choke groove and the 2nd choke groove short-circuit the electromagnetic waves corresponding to the wavelength of a specific frequency, respectively. Thereby, when performing transmission / reception of electromagnetic waves whose frequency changes with time, electromagnetic waves can be prevented from leaking from the gaps between the bonded surfaces of the bonded substrates.

  According to the invention of claim 2 in particular, the first choke groove and the second choke groove are provided on the side where the other adjacent waveguides exist with respect to each of the plurality of waveguides. It is possible to prevent an electromagnetic wave transmitted through one waveguide from affecting an electromagnetic wave transmitted through another adjacent waveguide.

  In particular, according to the invention of claim 3, it is possible to effectively prevent leakage of electromagnetic waves whose frequency changes temporally between the upper limit frequency and the lower limit frequency.

  In particular, according to the invention of claim 4, since the electromagnetic wave is transmitted and received inside the waveguide by using the substrate structure having the choke structure based on the frequency modulation, the leakage of the electromagnetic wave can be prevented and the accuracy is high. An object can be detected.

FIG. 1 is a diagram showing the configuration of the first substrate body. FIG. 2 is a cross-sectional view of the substrate body viewed from the position II-II in FIG. FIG. 3 is an enlarged view of a part of the substrate structure of FIG. FIG. 4 is a cross-sectional view of the substrate body viewed from the position IV-IV in FIG. FIG. 5 is a diagram showing the configuration of the second substrate body. FIG. 6 is a cross-sectional view of the substrate body viewed from the position VI-VI in FIG. FIG. 7 is a diagram showing the configuration of the third substrate body. 8 is a cross-sectional view of the substrate body as viewed from the position VIII-VIII in FIG. FIG. 9 is an overview of the radar apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram illustrating a configuration of a substrate body according to the first embodiment. 2 is a cross-sectional view of the substrate body 1 as viewed from the position II-II in FIG. The substrate body 1 has a substrate structure in which a plurality of substrates are stacked and bonded together. In the following, directions are appropriately indicated using XYZ orthogonal coordinate axes shown in the drawing. The orthogonal coordinate axes of XYZ are fixed relative to the substrate body 1, the longitudinal direction of the substrate body 1 is the X-axis direction, the direction in which the plurality of substrates of the substrate body 1 are stacked is the Y-axis direction, The short side direction of the substrate body 1 corresponds to the Z-axis direction.

  The substrate body 1 includes a high-frequency circuit board 11a on the upper side (−Y direction) on which a plurality of substrates are stacked, and has a bonding surface with another substrate on the back side (+ Y direction) of the high-frequency circuit board 11a. is doing. On the back surface of the substrate, a voltage controlled oscillator (VCO) 101, a high frequency circuit unit (MMIC) 102, a transmission line 103, a waveguide 105, and a choke groove 106a are provided.

  Here, the substrate body 1 is configured by laminating a plurality of substrates, and the plurality of substrates are joined so as to communicate with the waveguide 105 that transmits an electromagnetic wave whose frequency changes temporally between an upper limit frequency and a lower limit frequency. Has been. Hereinafter, the substrate refers to various plates such as a dielectric substrate and a metal substrate.

  The voltage controlled oscillator 101 outputs a frequency-modulated electromagnetic wave to the high frequency circuit unit 102 in accordance with a triangular wave frequency modulation signal. For example, the electromagnetic wave frequency-modulated with 38 GHz as the center frequency is output to the high-frequency circuit 102.

  The high frequency circuit unit 102 multiplies and amplifies the output power from the voltage controlled oscillator 101 and transmits the electromagnetic wave to the waveguide 105 through the transmission path 103. In the present embodiment, the frequency of the frequency-modulated electromagnetic wave having a center frequency of 36 GHz from the voltage controlled oscillator 101 is multiplied to set the center frequency to 76.5 GHz, the upper limit frequency to 76.7 GHz, and the lower limit. The description will be made based on an electromagnetic wave having a frequency of 76.3 GHz. However, frequency modulation may be performed between an arbitrary upper limit frequency and a lower limit frequency with a frequency other than this as a center frequency.

  The transmission line 103 is a line that transmits electromagnetic waves from the high-frequency circuit unit 102 to the waveguide 105 in the case of transmission, and transmits electromagnetic waves from the waveguide 105 to the high-frequency circuit unit 102 in the case of reception.

  The waveguide 105 serves as a transmission path from the high-frequency circuit unit 102 to the antenna board 13a via the transmission path 103 when electromagnetic waves are transmitted from the antenna board 13a. Further, when receiving electromagnetic waves, it becomes a transmission path from the antenna substrate 13 a to the high frequency circuit section 102 via the transmission path 103.

  The size of the waveguide 105 varies depending on the frequency band of the electromagnetic wave to be transmitted. The approximate size of the opening of the waveguide 105 based on the frequency band of 76 GHz used in this embodiment is about 2.5 mm in the horizontal direction (Z-axis direction) and about 2.5 mm in the vertical direction (X-axis direction). The dimension is 1.3 mm.

  The choke groove 106 a is a groove provided on a joint surface between the high-frequency circuit board 11 a and another substrate, and is provided so as to surround the periphery of the waveguide 105. As will be described in detail below, the high-frequency circuit board 11a is provided at a predetermined position from the waveguide 105 on the joint surface side with another board. Here, the predetermined position is a position corresponding to the wavelength of the frequency selected from the range from the upper limit frequency to the lower limit frequency in the electromagnetic wave whose frequency changes temporally between the upper limit frequency and the lower limit frequency. The choke groove 106 a has a depth corresponding to a predetermined position from the waveguide 105.

  As shown in FIG. 2, the substrate body 1 is composed of a plurality of substrates including a high-frequency circuit substrate 11a, a metal substrate 12a, and an antenna substrate 13a. As described above, the high-frequency circuit board 11a includes the voltage-controlled oscillator 101, the high-frequency circuit unit 102, the transmission line 103, the waveguide 105, and the choke groove 106a. Performs transmission wave and reception wave processing.

  The metal substrate 12a is a substrate for connecting the high-frequency circuit substrate 11a to an antenna substrate 13a described later, and is directly joined to the high-frequency circuit substrate 11a and guided to a position where it communicates with a waveguide of another substrate. A tube 105 is provided. Further, the position of the choke groove 106a provided in the high-frequency circuit board 11a on the bonding surface with the high-frequency circuit board 11a on the surface side (−Y direction) of the metal substrate 12a with respect to the position from the waveguide 105, The choke groove 106b having a depth different from the depth of the choke groove 106a is provided so as to surround the periphery of the waveguide 105 at different positions.

  That is, the choke groove 106a provided in the high-frequency circuit board 11a and the choke groove 106b provided in the metal substrate 12a are different in the distance from the waveguide 105 to the choke groove and the depth of the choke groove. The distance and the depth correspond to different frequencies selected in the range from the upper limit frequency to the lower limit frequency of the electromagnetic wave transmitted through the waveguide 105 with the respective choke grooves as a reference.

  Among them, λa is a wavelength based on the upper limit frequency of the electromagnetic wave to be frequency-modulated, and λb is a wavelength based on the lower limit frequency of the electromagnetic wave to be frequency-modulated, whereby the frequency is temporally changed between the upper limit frequency and the lower limit frequency. Electromagnetic leakage can be effectively prevented.

  In this embodiment, as an example, the wavelength at the lower limit frequency is λa, and the wavelength at the upper limit frequency is λb.

The lower limit frequency is 76.3 GHz, and the upper limit frequency is 767 GHz. The wavelength of the lower limit frequency (hereinafter also referred to as λa) is the speed of light (approximately 3 × 10 ⁸ m / s) at the lower limit frequency of 76.3 GHz. The value obtained by the division is about 3.93 mm.

The wavelength of the upper limit frequency (hereinafter also referred to as λb) is a value obtained by dividing the speed of light (about 3 × 10 ⁸ m / s) by the frequency of the upper limit frequency of 76.7 GHz, and is about 3.91 mm. A value of ¼ of each of λa and λb corresponds to the position and depth of the choke groove from the waveguide.

  In FIG. 2, the choke groove 106a of the high-frequency circuit board 11a is provided at a position approximately λa / 4 away from the waveguide 105 and has a depth of approximately λa / 4. The choke groove 106b of the metal substrate 12a is provided at a position approximately λb / 4 away from the waveguide 105 and has a depth of approximately λb / 4.

  The choke groove 106 a and the choke groove 106 b are provided so as to surround the periphery of the waveguide 105. Thus, by providing choke grooves based on different frequencies on the substrate bonding surfaces of the respective substrates, frequency-modulated electromagnetic waves passing through the gaps between the bonding surfaces of the high-frequency circuit board 11a and the metal substrate 12a are generated in the choke grooves 106a and It proceeds in the reverse direction by the choke groove 106b. Then, a standing wave is generated by a traveling wave that has penetrated into the gap at the joint surface later, and a node of the standing wave is formed at the entrance portion of the gap at the joint surface, thereby electrically shorting the electromagnetic wave. And electromagnetic leakage from the gap can be prevented.

  Thereby, leakage of electromagnetic waves close to the lower limit frequency is prevented in the choke groove 106a, and leakage of electromagnetic waves close to the upper limit frequency is prevented in the choke groove 106b. Therefore, even the electromagnetic wave whose frequency changes with time can be prevented from leaking by any one of the choke grooves 106a and 106b.

  In the present embodiment, it has been described that the choke groove is provided with the wavelength of the lower limit frequency being λa and the wavelength of the upper limit frequency being λb. However, any frequency within the range from the upper limit frequency to the lower limit frequency is described. It may be λa.

  Further, any frequency may be used as λb as long as the frequency is different from λa within the range from the upper limit frequency to the lower limit frequency. Further, in the present embodiment, the position of the choke groove from the waveguide and the depth from the position are set to 1/4 of the wavelengths λa and λb, but the odd multiple of 3/4 or 5/4, etc. Also good.

  The choke groove is an electromagnetic wave in a high frequency band of about 76 GHz as described above, and a groove having the same depth is provided at a position corresponding to the wavelength of the electromagnetic wave to be frequency-modulated. When a plurality of substrates are generated on the same plane of the substrate, the distance between the respective choke grooves becomes very close, making it difficult to provide the choke grooves. However, by generating choke grooves based on different frequencies separately for the high-frequency circuit board 11a and the metal board 12a as described above, the machining accuracy of the choke grooves is lowered and the manufacture becomes easy.

  FIG. 3 is an enlarged view of a part of the region RE of the substrate structure of FIG. In the region RE, a gap 107 is formed on the joint surface between the high-frequency circuit board 11a and the metal substrate 12a. The gap 107 is formed on the bonding surface between the substrates due to warpage of each substrate to be bonded, unevenness of the bonding surface, and the like.

  A choke groove 106a is provided at a position away from the waveguide 105 by ¼ of λa (in the + X direction). The depth (−Y direction) of the choke groove 106 a is λa / 4, which is the same as the distance from the waveguide 105.

  Further, a choke groove 106b is provided at a position (in the + X direction) that is ¼ of λb away from the waveguide 105. The depth (+ Y direction) of the choke groove 106b is λb / 4, which is the same as the distance from the waveguide 105.

  In the present embodiment, in the relationship between λa / 4 and λb / 4, the length of the wavelength is in a relationship of λa> λb, and the choke groove 106a of λa / 4 is formed on the back surface side (+ Y direction) of the high-frequency circuit board 11a. ) And the λb / 4 choke groove 106b is provided on the front surface side (−Y direction) of the metal substrate 12a, but the λb / 4 choke groove 106b is provided on the back surface side (+ Y direction) of the high-frequency circuit board 11a. It is also possible to provide a λa / 4 choke groove 106a on the surface side (−Y direction) of the metal substrate 12a.

  Returning to FIG. 2, on the back surface side (+ Y direction) of the metal substrate 12a, the electromagnetic wave transmission / reception surface (+ Y direction) of the antenna substrate 13a and the back surface side (-Y direction) opposite to the opposite direction are joined. The periphery of the waveguide 105 on the back surface side (+ Y direction) of the metal substrate 12a is at a depth of ¼ of the wavelength λa at a position away from the waveguide 105 by ¼ of λa (+ X direction and −X direction). A (-Y direction) choke groove 106a is provided. The choke groove 106a is provided so as to surround the periphery of the waveguide 105 of the metal substrate 12a.

  Further, the choke groove 106b of the antenna substrate 13a is provided at a quarter position (+ X direction and −X direction) that is λb away from the waveguide 105 and at a depth (¼ Y direction) of the wavelength λb. . The choke groove 106b is provided so as to surround the periphery of the waveguide 105 of the metal substrate 12a provided in the upper direction (−Y direction).

  In this way, a plurality of choke grooves based on electromagnetic waves that are frequency-modulated are provided in the gaps between the substrate bonding surfaces formed by the plurality of substrates stacked on the substrate body 1. Thereby, when performing transmission / reception of electromagnetic waves whose frequency changes with time, electromagnetic waves can be prevented from leaking from the gaps between the bonded surfaces of the bonded substrates.

  4 is a cross-sectional view of the substrate body 1 as viewed from the position IV-IV in FIG. The substrate body 1 includes a high-frequency circuit board 11a, a metal board 12a, and an antenna board 13a. The high-frequency circuit board 11a and the metal substrate 12a are provided with a waveguide 105, and the connected waveguide 105 is formed by joining the plurality of substrates. In order to prevent leakage of electromagnetic waves from the respective connection surfaces, choke grooves are provided.

  In the high-frequency circuit board 11a, a choke having a depth (−Y direction) λa / 4 is located at a position (λ direction) and λa / 4 away from the waveguide 105 (+ Z direction and −Z direction) based on a wavelength of λa. A groove 106 a is provided so as to surround the periphery of the waveguide 105.

  Further, on the surface side (−Y direction) which is a joint surface of the metal substrate 12a with the high frequency circuit board 11a, the metal substrate 12a is separated from the waveguide 105 by λb / 4 based on the wavelength of ¼ of λb of the high frequency circuit board 11a. Further, a choke groove 106b having a depth (+ Y direction) λb / 4 is provided at a position (+ Z direction and −Z direction) so as to surround the periphery of the waveguide 105.

  In addition, on the back surface side (+ Y direction) which is a joint surface of the metal substrate 12a with the antenna substrate 13a, the depth (−Y direction) is located at a position away from the waveguide 105 by λa / 4 (+ Z direction and −Z direction). A direction) λa / 4 choke groove 106 a is provided so as to surround the periphery of the waveguide 105.

  Furthermore, the depth (+ Y direction) is located at the position (λ) and λb / 4 away from the waveguide 105 (+ Z direction and −Z direction) on the joint surface with the metal substrate 12a on the back side (−Y direction) of the antenna substrate 13a. A λb / 4 choke groove 106b is provided so as to surround the periphery of the waveguide 105 of the metal substrate 12a.

In this way, when a plurality of substrates are joined, a choke groove corresponding to a different frequency is provided on each of the joint surfaces around the waveguide so that the electromagnetic waves whose frequency changes with time are joined. Electromagnetic waves can be prevented from leaking from the gaps between the bonding surfaces of the substrates.
<Second Embodiment>
FIG. 5 is a diagram showing the configuration of the substrate body 2 according to the second embodiment. In the following, description of the same configuration as that described in the first embodiment is omitted, and only different portions from the configuration of the first embodiment are described. The high-frequency circuit board 11 b of the substrate body 2 transmits electromagnetic waves from the high-frequency circuit unit 102 to the waveguide via the transmission line 13. In the first embodiment, the electromagnetic wave from one transmission path 103 is transmitted to one waveguide 105. However, in the second embodiment, a plurality of waveguides 105a are used. , 105b, 105c are provided.

  That is, as shown in FIG. 5, the transmission path 103 branches into three and transmits electromagnetic waves to the waveguide 105a, the waveguide 105b, and the waveguide 105c, respectively. Note that the frequency of the transmitted electromagnetic wave is the same in any waveguide, and when the frequency changes with time, the electromagnetic wave having a modulated frequency is supplied from the transmission path 103 to each waveguide. In this embodiment, the case where there are three waveguides will be described, but the present invention can be applied to a case where a plurality of waveguides other than three are provided.

  Next, FIG. 6 shows a cross-sectional view of the substrate body 2 viewed from the position VI-VI in FIG. A substrate body 2 including waveguides 105a, 105b, and 105c that communicate with a plurality of substrates of the high-frequency circuit substrate 11b, the metal substrate 12b, and the antenna substrate 13b and extend parallel to each other along the Y-axis direction is formed. Yes.

  The substrate body 2 having a substrate structure in which a plurality of substrates 11b, 12b, and 13b are joined is provided with a plurality of waveguides of a waveguide 105a, a waveguide 105b, and a waveguide 105c. A choke groove in which the wavelengths λa and λb having the frequencies described in the first embodiment are reversed is provided around each waveguide.

  Specifically, in the high-frequency circuit board 11b, the waveguides 105a, 105b, and 105c are surrounded by λb / so as to surround the waveguides 105a, 105b, and 105c. A choke groove 106b having a depth (−Y direction) λb / 4 is provided at a position 4 away (+ Z direction and −Z direction).

  In addition, on the surface side (−Y direction) which is a joint surface of the metal substrate 12b with the high frequency circuit substrate 11b, at a position away from the waveguides 105a, 105b and 105c by λa / 4 (+ Z direction and −Z direction), A choke groove 106a having a depth (+ Y direction) λa / 4 is provided so as to surround each waveguide.

  Further, on the back surface side (+ Y direction) which is a joint surface of the metal substrate 12b with the antenna substrate 13b, the depth is at a position away from the waveguides 105a, 105b, 105c by λb / 4 (+ Z direction and −Z direction). A choke groove 106a of (−Y direction) λb / 4 is provided so as to surround each waveguide.

  Further, the depth (+ Y direction) is located at the position (λ direction) in which the antenna substrate 13b is bonded to the metal substrate 12b (−Y direction) and separated from the waveguides 105a, 105b, 105c by λa / 4 (+ Z direction and −Z direction). ) A λa / 4 choke groove 106a is provided so as to surround the periphery of the waveguide 105 of the metal substrate 12b.

Even when a plurality of waveguides are provided in this way, by providing choke grooves corresponding to different frequencies on the joint surfaces when a plurality of substrates are joined, around each of the plurality of waveguides. When electromagnetic waves whose frequency changes with time are transmitted and received, electromagnetic waves can be prevented from leaking from the gaps between the bonded surfaces of the bonded substrates.
<Third Embodiment>
FIG. 7 is a diagram showing the configuration of the substrate body according to the third embodiment. In the following, description of the same configuration as that described in the first and second embodiments is omitted, and only parts different from the configurations of the first and second embodiments are described.

  In FIG. 7, in the plurality of waveguides 105a, 105b, and 105c of the high-frequency circuit board 11c of the substrate body 3, choke grooves corresponding to different frequencies are provided on the bonding surfaces when the plurality of substrates are bonded.

  However, unlike the second embodiment, the choke groove is provided only on the side where another adjacent waveguide exists, with respect to each of the plurality of waveguides. Specifically, in the waveguide 105b of FIG. 7, the other adjacent waveguide 105a exists in the −Z direction, and the waveguide 105c exists in the + z direction. Therefore, a choke groove 106b is provided on the side where each waveguide exists. That is, the choke groove 106b is provided so as to surround the periphery of the waveguide 105b.

  Next, since the waveguide 105a has another waveguide 105b adjacent in the + Z direction, a choke groove 106d is provided. However, since there is no other adjacent waveguide 105b in the −Z direction, no choke groove is provided. That is, in the waveguide 105a, more than a half circumference around the waveguide 105a in the + Z direction on the side where another waveguide is adjacent (both long sides of the waveguide 105a and the other waveguide 105b are adjacent to each other). A choke groove 106d is provided so as to surround the short side).

  Since the waveguide 105c has another waveguide 105b adjacent in the -Z direction, a choke groove 106d is provided. However, no choke groove is provided in the + Z direction because there is no other adjacent waveguide. That is, in the waveguide 105c, more than half a circumference around the waveguide 105c in the -Z direction on the side where the other waveguide 105b is adjacent (both long sides of the waveguide 105c and the other waveguide 105b). The choke groove 106d is provided so as to surround the short side of the adjacent side.

  FIG. 8 is a cross-sectional view of the substrate body 3 as viewed from the position VIII-VIII in FIG. On the back surface side (+ Y direction) of the high-frequency circuit board 11c, a choke groove 106b having a depth (−Y direction) λb / 4 is guided to a position (λ direction) and λb / 4 away from the waveguide 105b (+ Z direction and −Z direction). It is provided so as to surround the periphery of the wave tube 105b.

  In the waveguide 105a on the back surface side of the high-frequency circuit board 11c, a choke groove having a depth (−Y direction) λb / 4 is located at a position separated by λb / 4 on the side where the other waveguide 105b exists (+ Z direction). 106c is provided.

  In the waveguide 105c on the back surface side of the high-frequency circuit board 11c, a choke having a depth (−Y direction) λb / 4 is located at a position separated by λb / 4 on the side where the other waveguide 105b exists (−Z direction). A groove 106d is provided.

  In addition, on the surface side (−Y direction) which is a joint surface of the metal substrate 12c with the high frequency circuit substrate 11c, the depth (+ Y) is located at a position λa / 4 away from the waveguide 105b (+ Z direction and −Z direction). Direction) A choke groove 106a of λa / 4 is provided so as to surround the periphery of the waveguide 105b.

  In the waveguide 105a on the surface side of the metal substrate 12c, on the side where the other waveguide exists (+ Z) based on the wavelength ¼ of the wavelength λa selected from the range from the upper limit frequency to the lower limit frequency. The choke groove 106c having a depth (−Y direction) λa / 4 is provided at a position away from λa / 4 in the direction).

  In the waveguide 105c on the surface side of the metal substrate 12b, a choke groove having a depth (−Y direction) λa / 4 is located at a position separated by λa / 4 on the side where the other waveguide 105b exists (−Z direction). 106c is provided.

  Further, on the back surface side (+ Y direction) which is a joint surface of the metal substrate 12c with the antenna substrate 13c, the depth (−Y direction) is located at a position λb / 4 away from the waveguide 105b (+ Z direction and −Z direction). ) A λb / 4 choke groove 106b is provided so as to surround the periphery of the waveguide 105b.

  In the waveguide 105a on the back surface side of the metal substrate 12c, a choke groove 106d having a depth (−Y direction) λb / 4 is located at a position separated by λb / 4 on the side where the other waveguide 105b exists (+ Z direction). Is provided.

  In the waveguide 105c on the back side of the metal substrate 12c, a choke groove having a depth (−Y direction) λb / 4 is located at a position separated by λb / 4 on the side where the other waveguide 105b exists (−Z direction). 106d is provided.

  Further, on the back side of the antenna substrate 13c (−Y direction), a wave is guided through the choke groove 106a having a depth (+ Y direction) λa / 4 at a position (λ direction) that is λa / 4 away from the waveguide 105b (+ Z direction and −Z direction). It is provided so as to surround the periphery of the tube 105b.

    In the waveguide 105a joined to the back side of the antenna 13c, a choke having a depth (−Y direction) λa / 4 is located at a position separated by λa / 4 on the side where the other waveguide 105b exists (+ Z direction). A groove 106c is provided.

  In the waveguide 105c joined to the back side of the antenna 13c, the depth (−Y direction) of λa / 4 is located at a position separated by λa / 4 on the side where the other waveguide 105b exists (−Z direction). A choke groove 106c is provided.

  By providing choke grooves corresponding to different frequencies on the joint surfaces when a plurality of substrates are joined in this way on the side where another adjacent waveguide exists, the electromagnetic wave transmitted by one waveguide Can be prevented from affecting electromagnetic waves transmitted through other adjacent waveguides. Further, by not providing the choke groove on the side where there is no adjacent waveguide, it is possible to reduce the substrate processing cost and facilitate the processing process.

  FIG. 9 shows an overview of the radar device 5. As shown in FIG. 9, by using any of the substrate bodies 1, 2 and 3 described so far for the radar device 5, a substrate structure having a choke structure corresponding to frequency modulation can be used. Leakage of electromagnetic waves can be prevented during transmission of electromagnetic waves, and highly accurate objects can be detected.

  In addition, the substrate structure of the above-described embodiment is an electronic scan radar that estimates the angle based on the phase difference of each received electromagnetic wave, even if it is a mechanical scan radar device that mechanically scans the antenna. Even an apparatus can be used.

DESCRIPTION OF SYMBOLS 1 ... Board | substrate body 11a ... High frequency circuit board 12a ... Metal substrate 13a ... Antenna board 101 ... Voltage-controlled oscillator 102 ... High frequency circuit part 103 ... Transmission path 105 ... Conduction Wave tube 106a ... Choke groove

Claims (4)

A substrate structure in which a plurality of substrates are joined so as to communicate a waveguide that transmits an electromagnetic wave whose frequency changes temporally between an upper limit frequency and a lower limit frequency,
A wavelength of the electromagnetic wave having a first frequency selected from a range from the upper limit frequency to the lower limit frequency is λa;
The wavelength of the electromagnetic wave having a second frequency different from the first frequency selected from the range from the upper limit frequency to the lower limit frequency is λb,
And each
A first choke groove having a depth of approximately λa / 4, provided at a position approximately λa / 4 away from the waveguide on the side of the bonding surface with the other substrate in one of the substrates bonded to each other;
A second choke groove having a depth of approximately λb / 4 provided at a position approximately λb / 4 away from the waveguide on the joint surface side with the one substrate in the other substrate;
A substrate structure comprising: The substrate structure according to claim 1, wherein
A plurality of waveguides each communicating the plurality of substrates and extending parallel to each other;
With
The substrate structure according to claim 1, wherein the first choke groove and the second choke groove are provided on a side where another adjacent waveguide exists with respect to each of the plurality of waveguides. The substrate structure according to claim 1 or 2,
The first frequency is the lower limit frequency,
The second frequency is the upper limit frequency,
A substrate structure characterized by the following. A substrate body having the substrate structure according to claim 1;
A high-frequency circuit that is provided on the substrate body and generates an electromagnetic wave whose frequency changes temporally between the upper limit frequency and the lower limit frequency;
A radar apparatus comprising: