Double-sided substrate, radar device, transmission member, and method for manufacturing a transmission member

Abstract

The double-sided substrate (32) includes a first conductor layer (L1, L8), a second conductor layer (L1, L8), a waveguide-filled dielectric layer (P3-P5), and a waveguide (36). The waveguide-filled dielectric layer (P3-P5) is a dielectric layer disposed between the first conductor layer and the second conductor layer. The waveguide (36) is disposed through the waveguide-filled dielectric layer in a direction extending from either of the two conductor layers (the first and second conductor layers) to the other. The cross-section of the waveguide on a plane parallel to the first conductor layer has a long side direction and a short side direction orthogonal to the long side direction. The cross-section of the waveguide is divided into a central portion along the long side direction and ends located on both sides of the central portion. The length of the short side direction of the ends is longer than the length of the short side direction of the central portion.

Description

[0001] Cross-references to related applications

[0002] This application is based on Japanese Application No. 2020-038397, filed on March 6, 2020, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a double-sided substrate, a radar device, a transmission component, and a method for manufacturing the transmission component. Background Technology

[0004] For example, Patent Document 1 describes a double-sided substrate that transmits signals from one side of the two sides of the substrate to the other via a waveguide with a generally rectangular cross-sectional shape.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-180020

[0006] In order to reduce the loss when using waveguides to transmit signals, it is necessary to extend the length of the long side of the waveguide to a certain extent, which may become a constraint on the miniaturization of double-sided substrates. Summary of the Invention

[0007] The double-sided substrate that solves the above-mentioned problem includes: a first conductor layer (L1, L8); a second conductor layer (L1, L8); a waveguide-filled dielectric layer (P3 to P5), which is a dielectric layer disposed between the first conductor layer and the second conductor layer; and a waveguide (36), which is disposed through the waveguide-filled dielectric layer in a direction that extends from either of the first conductor layer to the other. The cross-section of the waveguide on a plane parallel to the first conductor layer has a long side direction and a short side direction orthogonal to the long side direction. The cross-section of the waveguide is divided into a central portion along the long side direction and ends located on both sides of the central portion. The length of the short side direction of the ends is longer than the length of the short side direction of the central portion.

[0008] There is a tendency that the longer the waveguide's long side, the lower the frequency at which transmission loss decreases. Here, according to the structure described above, by forming the waveguide's cross-section such that the length of the short side at the ends is longer than the length of the short side at the center, the frequency at which transmission loss decreases can be reduced compared to the case where the lengths of the short sides are equal at both ends and the center, while keeping the lengths of the long side the same. Therefore, in the above structure, compared to the case where the lengths of the short sides are equal at both ends and the center, the length of the long side can be shortened, thus achieving a suitable balance between reducing signal transmission loss using the waveguide and miniaturizing the double-sided substrate. Attached Figure Description

[0009] The above-mentioned objects, as well as other objects, features, and advantages of this disclosure, will become clearer with reference to the accompanying drawings and through the following detailed description.

[0010] Figure 1 This is an exploded perspective view showing the structure of a radar device according to one embodiment.

[0011] Figure 2 This is a diagram illustrating the configuration of the radar device according to the above-described embodiment.

[0012] Figure 3 This is a cross-sectional view showing the cross-sectional structure of the double-sided substrate according to the above embodiment.

[0013] Figure 4 This is an exploded perspective view showing the structure of the double-sided substrate according to the above embodiment.

[0014] Figure 5 This is a diagram showing the component connected to the first-side conversion unit in the above embodiment.

[0015] Figure 6 This is a top view showing the eighth-side conversion unit and the antenna in the above embodiment.

[0016] Figure 7 This is a cross-sectional view showing the cross-sectional structure of the waveguide according to the above embodiment.

[0017] Figure 8 (a)~ Figure 8 (c) is a diagram used to illustrate the technical significance of the waveguide in the above-described embodiments.

[0018] Figure 9 (a)~ Figure 9 (d) is a cross-sectional view showing the waveguide forming process of the above embodiment.

[0019] Figure 10 This is a top view showing the shape of the gap in the above-described embodiment.

[0020] Figure 11 (a) represents the layout of the waveguide in the above embodiment. Figure 11 (b) and Figure 11 (c) indicates the waveguide layout in the comparative example.

[0021] Figure 12 (a) and Figure 12 (b) is a top view showing the electric field distribution in the above-described embodiments and comparative examples. Detailed Implementation

[0022] Hereinafter, an embodiment of the double-sided substrate will be described with reference to the accompanying drawings.

[0023] Figure 1 The structure of the radar device 10 according to this embodiment is shown. The radar device 10 is a device that houses a shielding plate 14, an electromagnetic wave absorber 16, and a double-sided substrate 18 within a space divided by a radome 12 and a lower housing 20, and a connector 22 is mounted on the lower housing 20. Here, the shielding plate 14 is a metal plate used to suppress unwanted noise electromagnetic waves from the outside from entering the double-sided substrate 18. In addition, the electromagnetic wave absorber 16 is a component that absorbs electromagnetic waves to suppress diffuse reflection of electromagnetic waves in the portion of the double-sided substrate 18 covered by the shielding plate 14.

[0024] Figure 2 The configuration of radar device 10 is illustrated. Figure 2 The text describes an example of a radar device 10 being configured with one radar in the center of the front of a vehicle VC and one radar on each side of the rear.

[0025] Figure 3 This shows the cross-sectional structure of the double-sided substrate 18. The double-sided substrate 18 is a substrate formed by sequentially stacking 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. Either the first conductor layer L1 or the eighth conductor layer L8 functions as a first type of conductor layer, and either of them functions as a second type of conductor layer. Furthermore, as... Figure 8 As shown, in the following, the stacking direction is defined as the z-direction. In other words, the direction (first direction) from either the first conductor layer L1 or the eighth conductor layer L8 towards the other is defined as the z-direction. In particular, the direction from the first conductor layer L1 to the eighth conductor layer L8 is defined as the positive z-direction.

[0026] Here, the first dielectric layer P1, the second dielectric layer P2, the third dielectric layer P3, the fourth dielectric layer P4, the fifth dielectric layer P5, the sixth dielectric layer P6, and the seventh dielectric layer P7 are all made of resin material. Specifically, in this embodiment, epoxy resin with a glass cloth substrate is exemplified as the material for the second dielectric layer P2, the third dielectric layer P3, the fourth dielectric layer P4, the fifth dielectric layer P5, and the sixth dielectric layer P6. Polyphenylene ether resin is exemplified as the material for the first dielectric layer P1 and the seventh dielectric layer P7.

[0027] For convenience, the double-sided substrate 18 will be categorized below as a first outer layer 30, an inner layer 32, and a second outer layer 34. The first outer layer 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 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 34 includes a sixth dielectric layer P6, a seventh conductor layer L7, a seventh dielectric layer P7, and an eighth conductor layer L8.

[0028] A waveguide 36 is provided in the inner layer 32 in a manner that penetrates the inner layer 32. In addition, 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 32 are all grounded, forming a ground plane.

[0029] Figure 4 This is an exploded perspective view of the double-sided substrate 18.

[0030] like Figure 4 As shown, a microstrip line 52 and a first-side conversion section 50 are formed in the first conductor layer L1 to convert signals transmitted from either the waveguide 36 or the microstrip line 52 to the other.

[0031] like Figure 5 As shown, the first-side transition section 50 has a protrusion CP with a width greater than the linewidth of the microstrip line 52 at the connection point with the microstrip line 52, and cutouts SL are provided at both ends of the protrusion CP. The protrusion CP has the function of causing the impedance in the connection path between the microstrip line 52 and the first-side transition section 50 to change slowly. Furthermore, the function of the cutouts SL will be described in detail later. A monolithic microwave integrated circuit (MMIC54) is connected to the first-side transition section 50 via the microstrip line 52.

[0032] The MMIC 54 in this embodiment has two channel terminals for transmitting and three channel terminals for receiving. Therefore, a first-side conversion section 50 is formed in the first conductor layer L1 for each of these channels. Furthermore, the first-side conversion section 50 for transmitting serves as a component for converting high-frequency signals from the MMIC 54 into electromagnetic waves and outputting them to the waveguide 36. In addition, the first-side conversion section 50 for receiving serves as a component for converting electromagnetic waves from the waveguide 36 into high-frequency signals output to the microstrip line 52.

[0033] The MMIC54 performs transmission processing, generating a high-frequency signal of 76–77 GHz and sending it to the microstrip line 52, and reception processing, receiving the high-frequency signal of 76–77 GHz input via the microstrip line 52. Additionally, the MMIC54 includes a mixer for combining the high-frequency signal transmitted through the transmission processing and the high-frequency signal received through the reception processing.

[0034] The MMIC 54 is connected to a microcomputer (microcomputer 56). The microcomputer 56 includes a CPU 56a and a memory 56b. The CPU 56a executes programs stored in the memory 56b. Here, the processing performed by the CPU 56a includes processing for controlling the transmission and reception of high-frequency signals based on the MMIC 54. In addition, the processing performed by the CPU 56a includes: calculating the relative distance and relative speed between the object reflecting the high-frequency signal transmitted from the radar device 10 and the radar device 10 based on the signal synthesized by the mixer described above; and transmitting the calculation results to the outside of the radar device 10 via connector 22.

[0035] Return to Figure 4 An antenna 62 and an eighth-side conversion section 60 are formed on the eighth conductor layer L8 to convert signals transmitted from either the antenna 62 or the waveguide 36 to the other.

[0036] like Figure 6 As shown, the eighth-side conversion section 60 has a protrusion CP with a width greater than the linewidth of the microstrip line 52 at the connection point with the antenna 62, and cutouts SL are provided at both ends of the protrusion CP. The protrusion CP has the function of causing the impedance in the connection path between the antenna 62 and the eighth-side conversion section 60 to change slowly. Furthermore, the function of the cutouts SL will be described in detail later.

[0037] like Figure 3 as well as Figure 4 As shown, a second side gap 38 is formed in the second conductor layer L2. Additionally, a via 42 is provided in the second dielectric layer P2. Specifically, the pattern obtained by projecting the via 42 perpendicularly onto a plane containing the second conductor layer L2 and orthogonal to the z-direction forms a pattern surrounding the second side gap 38. Furthermore, multiple vias 42 extend along the z-direction, thereby connecting the second conductor layer L2 and the third conductor layer L3. Therefore, the second conductor layer L2 is grounded, forming a ground plane.

[0038] Furthermore, a via 44 is provided in the first dielectric layer P1. Specifically, the pattern obtained by projecting the via 44 perpendicularly onto a plane containing the first conductor layer L1 and orthogonal to the z-direction is formed along the edge of the first side transition section 50, except near the connection point with the microstrip line 52. Additionally, the pattern obtained by projecting the via 44 perpendicularly onto a plane containing the first conductor layer L1 and orthogonal to the z-direction surrounds the pattern obtained by projecting the second side slot 38 perpendicularly onto the plane, except near the aforementioned connection point. This is a setting to reduce signal transmission loss between the microstrip line 52 and the first side transition section 50. In particular, in this embodiment, the pattern obtained by projecting the via 44 perpendicularly onto the plane is not included in the area sandwiched between a pair of cutouts SL. Furthermore, multiple vias 44 extend along the z-direction, thereby connecting the second conductor layer L2 and the first conductor layer L1.

[0039] A seventh side gap 40 is formed in the seventh conductor layer L7. Additionally, a via 46 is provided in the sixth dielectric layer P6. Specifically, the pattern obtained by projecting the via 46 perpendicularly onto a plane containing the seventh conductor layer L7 and orthogonal to the z-direction forms the pattern surrounding the seventh side gap 40. Furthermore, multiple vias 46 extend along the z-direction, thereby connecting the seventh conductor layer L7 and the sixth conductor layer L6. Thus, the seventh conductor layer L7 is grounded, forming a ground plane.

[0040] Furthermore, a via 48 is provided in the seventh dielectric layer P7. Specifically, the pattern obtained by projecting the via 44 perpendicularly to the plane containing the eighth conductor layer L8 and orthogonal to the z-direction is formed inside the eighth-side transition section 60, except near the connection point with the antenna 62. Additionally, the pattern obtained by projecting the via 44 perpendicularly to the plane containing the eighth conductor layer L8 and orthogonal to the z-direction surrounds the pattern obtained by projecting the seventh-side slot 40 perpendicularly to the plane. This is a setting to reduce signal transmission loss between the eighth-side transition section 60 and the antenna 62. In particular, in this embodiment, the pattern obtained by projecting the via 48 perpendicularly to the plane containing the eighth conductor layer L8 and orthogonal to the z-direction is not included in the area sandwiched between a pair of cutouts SL. Furthermore, multiple vias 48 extend along the z-direction, thereby connecting the seventh conductor layer L7 and the eighth conductor layer L8.

[0041] In this embodiment, the signal to be transmitted based on waveguide 36 is set as the base mode signal in the TE mode. This is because signal processing is easier to perform compared to transmitting signals of multiple modes.

[0042] Figure 7 This represents the cross-sectional shape of waveguide 36 on the xy plane, which is orthogonal to the z-direction.

[0043] like Figure 7 As shown, waveguide 36, in the xy plane, includes a rectangle with its shorter side in the x-direction and its longer side in the y-direction, and circles overlapping the two ends of the rectangle in the y-direction. Each circle has a diameter of length Wl, which is longer than the shorter side Ws of the rectangle. Here, the straight line Lim connecting the centers PO1 and PO2 of the two circles is parallel to the y-direction. Furthermore, the straight line Lim is located at the center of both ends of the waveguide 36 in the x-direction.

[0044] Therefore, the cross-sectional shape of the waveguide 36 in the xy plane is linearly symmetric with respect to the straight line Lim. Furthermore, the central PC of the waveguide 36 in the xy plane, between the centers PO1 and PO2 in the straight line Lim, is linearly symmetric with respect to the straight line Ln, which is orthogonal to Lim. In other words, the cross-sectional shape of the waveguide 36 has a shape that is linearly symmetric with respect to lines parallel to the long side and with respect to lines parallel to the short side.

[0045] In detail, in this embodiment, when the waveguide 36 is divided along the y-direction into a central portion 36a and end portions 36b located at both ends of the central portion 36a, the length Ln1e of the end portion 36b in the y-direction is less than "1 / 3" of the length Ln1 in the y-direction of the waveguide 36. Furthermore, the end portion 36b is the portion of the waveguide 36 whose length in the x-direction is longer than its length Ws.

[0046] The waveguide 36 is configured in this way to reduce the transmission loss of the signal being transmitted via the waveguide 36 in this embodiment. This will be explained below.

[0047] Figure 8 (a) illustrates a waveguide with a constant length at both ends in the y-direction (long side) and the x-direction (short side). This is equivalent to a rectangular waveguide, whose outer perimeter is defined by drilling holes in the substrate using a drill with a cutting diameter slightly smaller than the length h, thus resulting in a semi-circular cross-sectional shape in the xy-plane at both ends in the long side direction. Figure 8 The waveguide of shape shown in (a) has a length in the long side that is greater than the length of the waveguide in order to make the transmission loss within an acceptable range. Figure 7 The waveguide 36 shown has a long side length Ln1. This is presumably because the shielding frequency of the rectangular waveguide is inversely proportional to the length of its long side.

[0048] That is, as is known, the signal with the lowest shielding frequency among the signals to be transmitted based on the rectangular waveguide is the signal of the base mode in the TE mode. Specifically, in a boundary condition satisfying that the amplitude of the electric field at both ends along the long side of the rectangular waveguide is zero, the wavelength of the electric field in the y-direction is twice the length of the long side of the inner circumference of the rectangular waveguide. In this embodiment, setting the signal to be transmitted based on the rectangular waveguide as this single-mode signal simplifies control. Therefore, it is preferable to set the shielding frequency relative to this single-mode signal to be lower than the operating frequency of 76-77 GHx. On the other hand, the shielding frequency relative to this single-mode signal is inversely proportional to the length of the long side of the inner circumference of the rectangular waveguide. Therefore, the minimum length of the long side of the inner circumference of the rectangular waveguide creates a constraint due to the shielding frequency, which in turn creates a constraint on the length of the long side of the outer circumference of the rectangular waveguide.

[0049] Here, in Figure 8 In the case of the waveguide described in (a), although it is not strictly different from the rectangular waveguide, it is considered to be roughly equivalent to the rectangular waveguide. Therefore, it is speculated that in terms of transmitting the base mode signal in the TE mode as a signal with a higher frequency than the shielding frequency, it is necessary to ensure the length of the long side of the inner circumferential surface.

[0050] To mitigate the constraint of the length along the longer side, such as Figure 8 As shown in (b), the inventors studied a waveguide where the length of the short side at both ends in the long direction is longer than that at the center. Specifically, they studied an H-shape formed such that the length H of the short side at both ends in the long direction is longer than the length h of the short side at the center. More specifically, they studied a symmetrical cross-sectional shape with equal lengths Lh1, Lh2, Lh3, and Lh4 of the portions protruding in the positive x-direction and negative x-direction at each end. Furthermore, in Figure 8 In the waveguide shown in (b), the x-direction ends of the two ends in the y-direction are semi-circular because the outer periphery of the waveguide is determined by drilling holes in the substrate.

[0051] Figure 8 (c) indicates that Figure 8 The transmission loss Loss in (b) is calculated when the length H of the short sides at both ends of the waveguide in the long direction is varied. The transmission loss Loss indicates that the larger the absolute value of the negative value, the greater the loss. For example... Figure 8 As shown in (c), by increasing the length H, the transmission loss in the 76–77 GHz frequency range can be reduced. This is presumably because increasing the length H lowers the shielding frequency.

[0052] Furthermore, during the research process, no Figure 8 The length of the short side in the waveguide shown in (a) is always extended because in this case, it is equivalent to a rectangular waveguide with an increased length in the short side. On the other hand, it is theoretically known that increasing the length of the short side of a rectangular waveguide does not help to reduce the shielding frequency of the signal in the single mode mentioned above.

[0053] Given that through Figure 8 The study shown demonstrates the insight that it is effective to increase the length of the short sides at both ends of the long side of the waveguide. In this embodiment, a waveguide with... Figure 7 Waveguide 36 with the cross-sectional shape shown. Here, it is not used. Figure 8 The cross-sectional shape shown in (b) is due to the fact that, compared to repeatedly using a drill to create holes of length h at both ends to elongate the length in the short side direction, the method employed... Figure 9 The manufacturing process shown makes it easier to improve machining accuracy.

[0054] Figure 9 This indicates the manufacturing process of waveguide 36.

[0055] Figure 9 (a) indicates the cross-sectional structure at the moment when the fourth conductor layer L4, the third conductor layer P3 and the third conductor layer L3, the fifth conductor layer L5, the fifth conductor layer P5 and the sixth conductor layer L6 are stacked on both sides of the fourth dielectric layer P4, thereby forming the prototype component 32a, which is the prototype of the inner layer 32.

[0056] As Figure 9 The process following (a), Figure 9 (b) indicates the process of penetrating the prototype component 32a in the z-direction using a large-diameter drill 70 for creating a hole of length Wl. The diameter of the large-diameter drill 70 is slightly smaller than the length Wl. In this embodiment, the same large-diameter drill 70 is used to create two holes in the prototype component 32a to form a cavity HL.

[0057] As Figure 9 The process following (b), Figure 9 (c) indicates the process of penetrating the prototype component 32a in the z-direction using a small-diameter drill 72 for creating a hole of length Ws. The diameter of the small-diameter drill 72 is slightly smaller than the length Ws. In this embodiment, in order to... Figure 9 The pair of cavities HL formed in the process shown in (b) are connected, and holes are drilled multiple times on the prototype part 32a using a small-diameter drill bit 72.

[0058] As Figure 9 The process following (c), Figure 9(d) indicates the process of plating the inner circumferential surface of the prototype component 32a, which is divided into hollow sections, to form the waveguide 36.

[0059] like Figure 9 As shown, in this embodiment, the outer peripheral surface shape of both ends of the waveguide 36 in the long side direction is formed by drilling holes using a large-diameter drill bit 70 on the prototype component 32a. Furthermore, in Figure 9 After step (d), in the step of stacking the second dielectric layer P2 and the sixth dielectric layer P6, the waveguide 36 is also filled with dielectric.

[0060] Figure 10 This represents the shape of the second side slit 38 and the seventh side slit 40 on the xy plane. Figure 10 In the diagram, the cross-sectional shape of the outer peripheral surface of the waveguide 36 is shown together with dashed lines. This corresponds to a diagram obtained by projecting the waveguide 36 and the second side slot 38 perpendicularly to the z-direction and including the first conductor layer L1. Additionally, this corresponds to a diagram obtained by projecting the waveguide 36 and the seventh side slot 40 perpendicularly to the z-direction and including the eighth conductor layer L8.

[0061] like Figure 10 As shown, in this embodiment, both the second side gap 38 and the seventh side gap 40 have varying lengths at both ends in the long side direction (y-direction) and the short side direction (x-direction). Specifically, the length Ln2e of the portion in the short side direction that is longer than the central portion is "1 / 3" shorter than the length Ln2 in the long side direction.

[0062] Furthermore, such as Figure 10 As shown, in this embodiment, the pattern obtained by projecting the second side slot 38 and the seventh side slot 40 perpendicularly onto a plane orthogonal to the z-direction and including the first conductor layer L1 or the eighth conductor layer L8 is included in the pattern obtained by projecting the waveguide 36 perpendicularly onto the same plane. That is, the length Ln2 of the long side of the second side slot 38 and the seventh side slot 40 is shorter than the length Ln1 of the long side of the waveguide 36. Furthermore, the length Ln2e of the portion of the long side of the second side slot 38 and the seventh side slot 40 that is longer in the short side direction compared to the central portion is shorter than the length Ln1e of the portion of the long side of the waveguide 36 that is longer in the short side direction compared to the central portion.

[0063] Here, the function and effects of this embodiment will be explained.

[0064] Figure 11 (a) illustrates a portion of the configuration of the eighth-side conversion unit 60 and the antenna 62. Figure 11As shown in (a), in this embodiment, the configuration space in the y direction is reduced by arranging the waveguides 36 adjacently in the y direction.

[0065] Figure 11 (b) indicates the use of having Figure 8 A comparative example of waveguide 80 with the same configuration as shown in (a). In this case, as Figure 11 As shown in (b), waveguides 80 interfere with each other.

[0066] Figure 11 (c) indicates that the configuration is set to enable the following: Figure 8 Example (a) shows a pair of waveguides 80 with cross-sectional shapes that do not interfere with each other. In this case, as... Figure 11 As shown in (c), a wider space is required in the x-direction compared to this embodiment.

[0067] Thus, according to this embodiment, by studying the cross-sectional shape of the waveguide 36, the waveguide 36 can be easily arranged adjacently in the y direction, thereby making it easy to miniaturize the double-sided substrate 18.

[0068] Based on the above-described embodiment, the following functions and effects are further obtained.

[0069] (1) The outer periphery of the waveguide 36 is determined by the process of drilling two holes in parallel in the z-direction using a large-diameter drill bit 70 with a larger cutting diameter on the prototype component 32a, and by drilling holes in parallel in the z-direction using a small-diameter drill bit 72 with a smaller cutting diameter. Thus, with... Figure 8 Compared to waveguides with the cross-sectional shape shown in (b), it is easier to improve the processing accuracy, thus enabling the realization of waveguide 36 with excellent mass production capabilities.

[0070] (2) The process of connecting the two cavities HL using a small-diameter drill 72 with a smaller cutting diameter is as follows: Figure 9 Prior to the process shown in (c), a process is performed in which two holes are drilled in the z-direction using a large-diameter drill 70 with a larger cutting diameter to form the cavity HL. Figure 9 The process shown in (b) makes it easier to improve machining accuracy compared to reversing the two processes.

[0071] (3) Cutouts SL are provided at both ends of the connection portion between the first-side conversion section 50 and the microstrip line 52. This allows for suppression of... Figure 12 In (a), the electric field represented by a point is concentrated at both ends in the y direction of the first side conversion section 50, near the microstrip line 52, thus reducing electric field losses. In contrast, as... Figure 12As shown in (b), without the cutout SL, the transmission loss increases because electric field concentration occurs at both ends in the y direction near the microstrip line 52 at the x-direction end.

[0072] (4) The first side conversion section 50 and the second conductor layer L2 are connected by multiple through-holes 44. The pattern obtained by projecting the through-holes 44 perpendicularly to the z-direction and including the first side conversion section 50 is surrounded by the area of ​​the pattern obtained by projecting the waveguide 36 perpendicularly to the z-direction, excluding the area sandwiched by a pair of cutouts SL. It is not easy to form through-holes 44 in the area where cutouts SL are formed. Therefore, cutouts SL are provided in the area where it is not easy to form through-holes 44, so as to compensate for the electric field leakage caused by not providing through-holes 44.

[0073] (5) Cutouts SL are provided at both ends of the connection portion with the antenna 62 in the eighth-side conversion section 60. This allows for suppression of... Figure 12 In (a), the electric field is concentrated at both ends in the y-direction of the eighth-side conversion section 60 near the antenna 62, as indicated by the point, thus reducing electric field loss. In contrast, as... Figure 12 As shown in (b), without the notch SL, the transmission loss increases because electric field concentration occurs at both ends in the y direction near the antenna 62 at the x-direction end.

[0074] (6) The pattern obtained by connecting the eighth-side transition section 60 and the seventh conductor layer L7 through multiple through-holes 48, and by vertically projecting the through-holes 48 onto a plane orthogonal to the z-direction and including the eighth-side transition section 60, surrounds the portion of the pattern obtained by vertically projecting the waveguide 36 onto the plane, excluding the area sandwiched by a pair of cutouts SL. It is difficult to form through-holes 48 in areas where cutouts SL are formed; therefore, cutouts SL are provided in areas where it is difficult to form through-holes 48, thereby compensating for electric field leakage caused by the absence of through-holes 48.

[0075] (7) The pattern obtained by projecting the second side slot 38 perpendicularly onto a plane orthogonal to the z-direction and including the first conductor layer L1 is included in the pattern obtained by projecting the waveguide 36 perpendicularly onto the same plane. This reduces the size of the pattern corresponding to the second side slot 38, thereby sufficiently suppressing the exposure of the pattern obtained by projecting the second side slot 38 perpendicularly onto a plane orthogonal to the z-direction and including the first conductor layer L1 from the pattern obtained by projecting the waveguide 36 perpendicularly onto the same plane, even in the event of a positional shift during the manufacturing process. Therefore, even in the event of a positional shift during the manufacturing process, electric field leakage between the waveguide 36 and the first side conversion section 50 can be suppressed, thus reducing transmission losses between the waveguide 36 and the first side conversion section 50.

[0076] (8) A pattern obtained by connecting the second conductor layer L2 and the third conductor layer L3 through multiple through-holes 42, and by projecting these through-holes 42 perpendicularly onto a plane orthogonal to the z-direction and including the first conductor layer L1, surrounds the waveguide 36 projected perpendicularly onto that plane. This suppresses electric field leakage between the waveguide 36 and the first side conversion section 50, thereby reducing transmission losses between the waveguide 36 and the first side conversion section 50.

[0077] (9) The pattern obtained by projecting the seventh side slot 40, which is orthogonal to the z-direction and includes the eighth conductor layer L8, vertically into the pattern obtained by projecting the waveguide 36 vertically into the same plane. This reduces the size of the pattern corresponding to the seventh side slot 40, thus sufficiently suppressing the exposure of the pattern obtained by projecting the seventh side slot 40, which is orthogonal to the z-direction and includes the eighth conductor layer L8, from the pattern obtained by projecting the waveguide 36 vertically into the same plane, even in the event of a positional shift during the manufacturing process. Therefore, even in the event of a positional shift during the manufacturing process, electric field leakage between the waveguide 36 and the eighth side conversion section 60 can be suppressed, thereby reducing transmission losses between the waveguide 36 and the eighth side conversion section 60.

[0078] (10) A pattern obtained by connecting the sixth conductor layer L6 and the seventh conductor layer L7 through multiple vias 46, and by projecting these vias 46 perpendicularly onto a plane orthogonal to the z-direction and including the eighth conductor layer L8, surrounds the waveguide 36 projected perpendicularly onto that plane. This suppresses electric field leakage between the waveguide 36 and the eighth-side conversion section 60, thereby reducing transmission losses between the waveguide 36 and the eighth-side conversion section 60.

[0079] <Other Implementation Methods>

[0080] Furthermore, this embodiment can be modified as follows. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0081] Regarding the cross-sectional shape of waveguides

[0082] In the above embodiment, the long side direction of the cavity portion defining the outer periphery of the waveguide 36 is formed using the same drilling tool, thereby forming these cross-sectional shapes into identical circles, but this is not a limitation. For example, one cavity portion at each end can be formed using one of a pair of different drilling tools, and the other cavity portion at each end can be formed using the other. Here, if the specifications of the pair of drilling tools are the same, then the cross-sectional shapes of the two ends can be made into identical circles. However, the identical circles here allow for tolerances in the diameter of the pair of drilling tools.

[0083] In the above embodiment, the straight line Lim connecting the centers PO1, PO2 of a pair of circles at both ends of the cavity portion on the long side direction of the outer periphery of the waveguide 36 is parallel to the long side direction, but is not limited thereto, and may be intentionally slightly offset from parallel.

[0084] • The cross-sectional shape parallel to the xy-plane of the waveguide is not limited to a shape where a circle overlaps with the two ends of a rectangle. For example, it can also be as follows: Figure 8 The example shown is an H-shape. Even in this case, in order to clearly distinguish it from the rectangular waveguide with the length in the x-direction increased, it is preferable that the length in the y-direction is less than "1 / 3" of the overall length at the two ends with the longer length in the x-direction.

[0085] Furthermore, the H-shape is not limited to having a semi-circular end. For example, a drill with a smaller cutting diameter can be used to form a hollow portion that resembles a waveguide, thereby making the end shape as flat as possible.

[0086] Furthermore, as an H-shape, it is not limited to Figure 8 The lengths Lh1, Lh2, Lh3, and Lh4 are equal to each other. For example, lengths Lh2 and Lh3 can be equal, lengths Lh1 and Lh4 can be equal, and lengths Lh2 and Lh3 can be intentionally made longer than lengths Lh1 and Lh4. Furthermore, here, "equal" means that manufacturing tolerances are allowed.

[0087] • The extension direction of the waveguide, which is the axial direction of the waveguide, does not necessarily have to be parallel to the z-direction, which is the stacking direction; it can also be offset in this pair of directions.

[0088] Regarding gaps

[0089] • It is not necessary for the pattern obtained by projecting a light ray parallel to the extension direction of the waveguide (which is the axial direction of the waveguide) onto the plane orthogonal to the z-direction and including the first conductor layer L1 to be included in the pattern obtained by projecting the waveguide 36 onto the same plane. For example, the end of the pattern obtained by projecting the second side slot 38 onto the same plane perpendicularly may overlap with the end of the pattern obtained by projecting the waveguide 36 onto the same plane perpendicularly.

[0090] • The cross-sectional shape of the second side gap 38 in the xy plane is not limited to the two ends in the long side direction, but the shape in which the length in the short side direction is longer than the length in the central direction.

[0091] • It is not necessary for the pattern obtained by projecting a light ray parallel to the extension direction of the waveguide (which is the axial direction of the waveguide) onto the seventh side slit 40, which is orthogonal to the z-direction and includes the eighth conductor layer L8, to be included in the pattern obtained by projecting the waveguide 36 onto the plane. For example, the end of the pattern obtained by projecting the seventh side slit 40 onto the plane vertically may overlap with the end of the pattern obtained by projecting the waveguide 36 onto the plane vertically.

[0092] • The cross-sectional shape of the seventh side gap 40 in the xy plane is not limited to the two ends in the long side direction, but the shape in which the length in the short side direction is longer than the length in the central direction.

[0093] • In the above embodiment, the cross-sectional shapes of the second side gap 38 and the seventh side gap 40 are set to be the same, but it is not limited to this. In particular, for example, when the materials of the dielectric layer sandwiching the second conductor layer L2 and the dielectric layer sandwiching the seventh conductor layer L7 are different, or when there is a certain asymmetry in the structure, the cross-sectional shapes may be intentionally designed to be different.

[0094] Even when a second conductor layer L2 is provided, providing a second side gap 38 is not necessary. For example, as the second conductor layer L2, a conductor that does not contact the ground plane of the second conductor layer L2 may be provided within the second side gap 38.

[0095] Even when a seventh conductor layer L7 is provided, it is not necessary to provide a seventh side gap 40. For example, as the seventh conductor layer L7, a conductor that does not contact the ground plane of the seventh conductor layer L7 can be provided in the seventh side gap 40.

[0096] Regarding the Conversion Department

[0097] The protrusion CP provided in the first-side transition section 50 as the connection point with the microstrip line 52 is not limited to having a constant length in the y-direction; for example, it may have a shape in which the length in the y-direction decreases as it approaches the microstrip line 52. That being said, providing the protrusion CP in the first-side transition section 50 is not essential in itself.

[0098] • Forming a notch SL in the first-side transition section 50 is not necessary. For example, even if only the through hole 44 is provided, leakage of the electric field can be suppressed.

[0099] The protrusion CP provided as the connection point with the antenna 62 in the eighth-side conversion section 60 is not limited to having a constant length in the y-direction; for example, it may have a shape in which the length in the y-direction decreases as it approaches the antenna 62. That being said, providing the protrusion CP in the eighth-side conversion section 60 is not essential in itself.

[0100] • Forming a notch SL in the eighth-side transition section 60 is not necessary. For example, even if only the through hole 48 is provided, leakage of the electric field can be suppressed.

[0101] Regarding the surrounding conductor

[0102] • It is not necessary for the via 42 to contact the second conductor layer L2. This can be achieved, for example, by creating a via without penetrating the second dielectric layer P2 after the second conductor layer L2 has been stacked and formed, and filling the via with a conductor.

[0103] • It is not necessary for the via 42 to contact the third conductor layer L3. This can be achieved, for example, by creating a via without penetrating the second dielectric layer P2 after the second dielectric layer P2 has been stacked on the third conductor layer L3, and filling the via with a conductor.

[0104] • As an enclosure conductor, a cylindrical groove can also be formed in the second dielectric layer P2, and a conductor can be filled into the groove to provide a cylindrical conductor instead of providing a through hole 42.

[0105] For example, if it is difficult to form a via 46 in the second dielectric layer P2, the via 42 or other surrounding conductors may not be provided, such as when the first outer layer 30 is bonded to the inner layer 32.

[0106] • It is not necessary for the via 46 to contact the seventh conductor layer L7.

[0107] • It is not necessary for the via 46 to contact the sixth conductor layer L6.

[0108] • As an enclosing conductor, a cylindrical groove can also be formed in the sixth dielectric layer P6, and a conductor can be filled into the groove to provide a cylindrical conductor instead of providing a through hole 46.

[0109] For example, if it is difficult to form a via 46 in the sixth dielectric layer P6 when the second outer layer 34 is bonded to the inner layer 32, the via 46 or the surrounding conductor may not be provided.

[0110] Regarding protective conductors

[0111] • The via 44 may not be in contact with the second conductor layer L2.

[0112] • The through hole 44 may not be in contact with the first side conversion part 50.

[0113] • The protective conductor provided on the first dielectric layer P1 is not limited to being composed of multiple vias 44. For example, a conductor in the shape that connects the two vias 44 closest to each other may be provided, except between the two vias 44 closest to the connection point with the microstrip line 52.

[0114] • The pattern obtained by projecting the via 44 perpendicularly onto a plane orthogonal to the z-direction and containing the first conductor layer L1 is not necessarily contained in the cutout SL, or in the region sandwiched between a pair of cutouts SL.

[0115] • It is not necessary to provide a protective conductor such as a via 44 in the first dielectric layer P1.

[0116] • The via 48 may not be in contact with the seventh conductor layer L7.

[0117] • The through hole 48 may not be in contact with the eighth side conversion part 60.

[0118] • The protective conductor provided on the seventh dielectric layer P7 is not limited to being composed of multiple vias 48. For example, a conductor in the shape that connects the two vias 48 closest to each other may be provided, except between the two vias 48 closest to the connection point with the antenna 62.

[0119] • The pattern obtained by projecting the via 48 perpendicularly onto a plane orthogonal to the z-direction and containing the eighth conductor layer L8 is not necessarily contained in the cutout SL, or in the region sandwiched between a pair of cutouts SL.

[0120] • It is not necessary to provide a protective conductor such as a via 48 in the seventh dielectric layer P7.

[0121] Regarding double-sided substrates

[0122] For example, the fifth conductor layer L5 can be removed from the inner layer 32, and the inner layer 32 can be composed of three conductor layers and two dielectric layers. Alternatively, the fourth conductor layer L4 and the fifth conductor layer L5 can be removed from the inner layer 32, and the inner layer 32 can be composed of 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 can be removed from the inner layer 32, and a waveguide 36 can be embedded in the dielectric layer.

[0123] Alternatively, the second conductor layer L2 can be removed from the first outer layer 30, and the first outer layer 30 can be composed of a conductor layer and a dielectric layer.

[0124] Alternatively, the seventh conductor layer L7 can be removed from the second outer layer 34, and the second outer layer 34 can be composed of a conductor layer and a dielectric layer.

[0125] • It is not necessary to fill the inside of waveguide 36 with dielectric.

[0126] It is not necessary for the microstrip line 52 connecting the first-side transition section 50 and the MMIC 54 to be formed on the first conductor layer L1. For example, the MMIC 54 can also be directly connected to the first-side transition section 50.

[0127] • Not limited to the structure where MMIC54 is only connected to the first conductor layer L1. For example, the transmitting MMIC54 can also be connected to the first conductor layer L1, and the receiving MMIC54 can be connected to the eighth conductor layer L8. In other words, the receiving MMIC54 can also be connected to the antenna 62, so that the signal received by the antenna 62 can be transmitted to the MMIC54 without passing through the waveguide 36.

[0128] "Regarding the manufacturing process of waveguides"

[0129] In the above embodiment, after the first penetration step of the prototype component 32a through using the large-diameter drill 70, the second penetration step of the prototype component 32a through using the small-diameter drill 72 is performed. However, the order of the first penetration step and the second penetration step is not limited to this.

[0130] • The method for forming a cavity in the dielectric of the outer periphery of a specified waveguide is not limited to the method of using a drill, but may also be the method of using a laser.

[0131] "About waveguides"

[0132] • In the above embodiments, a waveguide is illustrated in which a signal higher than the shielding frequency, i.e., the signal to be transmitted, is only the base mode in the TE mode, but it is not limited thereto.

[0133] • In the above embodiments, the waveguide for transmitting and the waveguide for receiving are different, but it is not limited to this.

[0134] Regarding the configuration of waveguides

[0135] It is not necessary to arrange multiple waveguides adjacent to each other in the long direction. Even if multiple waveguides are not arranged adjacent to each other in the long direction, it is effective to shorten the length in the long direction by using the waveguides illustrated in the above embodiments and their modifications, while satisfying various configuration constraints. Furthermore, this is also the case when the double-sided substrate 18 and the radar device 10 have only a single waveguide.

[0136] Regarding the processing circuitry

[0137] In the above embodiment, the MMIC54 has multiple channels, but is not limited to this. For example, one MMIC can be provided for each of the multiple channels.

[0138] In the above embodiments, the MMIC54 and the microcomputer 56 that performs control of the MMIC54-based transceiver processing and analyzes the signals output by the MMIC54 are set as different components, but they can also be integrated.

[0139] Regarding the radar equipment

[0140] The number of transmitting antennas 62 and receiving antennas 62 is not limited to the cases illustrated in the above embodiments. For example, in the absence of phased array processing, only one transmitting antenna 62 may be provided.

[0141] • It is not limited to mounting the MMIC54 and the microcomputer56 on a single double-sided substrate 18. For example, the double-sided substrate with the MMIC54 and the substrate with the microcomputer56 can be set as different substrates.

[0142] • As a radar device, the output signal is not limited to a detection result signal that includes the relative speed and distance to objects outside the vehicle. For example, a signal used outside the radar device to calculate the relative speed and distance to objects outside the vehicle may also be set as the output signal.

[0143] • As a radar device for vehicles, it is not limited to a device that transmits and receives radar in the 76-77 GHz band. For example, it could also be a device that transmits and receives radar in the 76-80 GHz band, or, for example, 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.

[0144] "other"

[0145] • The material used as the dielectric layer is not limited to those exemplified in the above embodiments.

[0146] • The material used as the conductor layer is not limited to those exemplified in the above embodiments.

[0147] This disclosure is described based on embodiments, but it should be understood that this disclosure is not limited to those embodiments or constructions. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and methods, including only one element, one or more, or one or fewer of these elements, are also included in the scope and spirit of this disclosure.

Claims

1. A double-sided substrate, comprising: The first type of conductor layer; The second type of conductor layer; The waveguide is filled with a dielectric layer, which is a dielectric layer disposed between the first conductor layer and the second conductor layer; and A waveguide is provided by extending through a dielectric layer in a direction from either the first conductor layer or the second conductor layer towards the other. The waveguide's internal cross-section, located on a plane parallel to the first conductor layer, has a long side direction and a short side direction orthogonal to that long side direction. The internal cross-section of the waveguide is divided into a central portion along the long side and ends located on both sides of the central portion. The length of the short side of the end portion is longer than the length of the short side of the central portion.

2. The double-sided substrate according to claim 1, wherein, The waveguide on a plane parallel to the first conductor layer has an internal cross-sectional shape comprising a rectangle and circles overlapping the two ends of the long side of the rectangle. The diameter of the circle is longer than the length of the shorter side of the rectangle.

3. The double-sided substrate according to claim 1, wherein, In the internal cross-section of the waveguide on a plane parallel to the first conductor layer, the length of each end in the long side direction is less than 1 / 3 of the length of the long side direction of the waveguide.

4. The double-sided substrate according to claim 1, wherein, The waveguide is at least one of a first waveguide and a second waveguide. The first waveguide and the second waveguide are arranged adjacent to each other in the long side direction.

5. The double-sided substrate according to claim 1, wherein, The first type of conductor layer includes a transition section and a conductor connected to the transition section, i.e., a connecting conductor. The conversion section is a conductor that mediates the power transmission between the connecting conductor and the waveguide. The conversion section includes a portion connected to the connecting conductor and two ends located at both ends of the portion connected to the connecting conductor. Cutouts are formed at both ends.

6. The double-sided substrate according to claim 5, wherein, The direction of travel from either the first type of conductor layer or the second type of conductor layer towards the other is defined as the first direction. The double-sided substrate also features: The tube-opposed dielectric layer is composed of a dielectric material covering the end of one of the pair of ends of the waveguide that is close to the first conductor layer in a direction parallel to the first direction. The connecting conductor layer is a conductor layer stacked on the back side of the surface opposite the waveguide and opposite the first type of conductor layer in the tube-opposite dielectric layer; as well as The connecting dielectric layer is a dielectric layer sandwiched between the connecting conductor layer and the first type of conductor layer. A protective conductor is provided in the connecting dielectric layer. The pattern obtained by projecting the protective conductor perpendicularly onto a plane orthogonal to the direction parallel to the first direction and containing the first type of conductor layer is located outside the region sandwiched by the pair of cutouts.

7. The double-sided substrate according to claim 5 or 6, wherein, The connecting conductor is an antenna.

8. The double-sided substrate according to claim 5 or 6, wherein, The second type of conductor layer includes an antenna.

9. The double-sided substrate according to any one of claims 1 to 6, wherein, The direction of travel from either the first type of conductor layer or the second type of conductor layer towards the other is defined as the first direction. The double-sided substrate also features: The tube-opposed dielectric layer is composed of a dielectric material covering the end of one of the pair of ends of the waveguide that is close to the first conductor layer in a direction parallel to the first direction. The connecting conductor layer is a conductor layer stacked on the back side of the surface opposite the waveguide and opposite the first type of conductor layer in the tube-opposite dielectric layer; as well as The connecting dielectric layer is a dielectric layer sandwiched between the connecting conductor layer and the first type of conductor layer. The first type of conductor layer includes a transition section and a connecting conductor. The transition section is positioned opposite the waveguide, separated by the connecting dielectric layer, the connecting conductor layer, and the tube-opposite dielectric layer. The connecting conductor is a conductor connected to the transition section. The conversion section is a conductor that mediates the power transmission between the connecting conductor and the waveguide. A gap is formed between the connecting conductor layer and the conversion section. The pattern obtained by projecting the slit onto a plane orthogonal to the first direction and containing the first type of conductor layer is included in the pattern obtained by projecting the waveguide onto the same plane.

10. The double-sided substrate according to claim 9, wherein, A surrounding conductor is provided in the dielectric layer opposite the tube. The pattern obtained by projecting the surrounding conductor perpendicularly onto a plane that is orthogonal to the direction parallel to the first direction and contains the connecting conductor layer becomes the pattern surrounding the gap.

11. A radar device, wherein, One of the two conductor layers, the first conductor layer and the second conductor layer, includes an antenna. The other layer of the two layers is connected to a processing circuit that performs at least one of the two processes: high-frequency signal transmission processing and high-frequency signal reception processing. The radar device includes: The double-sided substrate as described in any one of claims 1 to 10; and The processing circuit.

12. The radar device according to claim 11, wherein, The radar device is mounted on a vehicle. The processing circuit performs the sending process and the receiving process. The receiving process is the process of receiving reflected waves from objects around the vehicle, which are sent by the transmitting process and are reflected by the high-frequency signal.

13. A transmission component, wherein, The waveguide and the waveguide-filled dielectric layer are provided in the double-sided substrate as described in any one of claims 1 to 10.

14. A method for manufacturing a transmission component, wherein, The method for manufacturing the transmission component as described in claim 13 comprises: The first penetration process involves using a large-diameter drill to penetrate the waveguide filling dielectric layer; and... In the second penetration process, a small-diameter drill bit with a smaller cutting diameter than the large-diameter drill bit is used to penetrate the waveguide filling dielectric layer. The first through-through process forms cavities corresponding to the two ends of the waveguide, and the second through-through process forms cavities corresponding to the portions connected to the two ends of the waveguide.

15. The method for manufacturing the transmission component according to claim 14, wherein, The first through-through process is performed before the second through-through process.

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