Waveguide member, waveguide device, and method for manufacturing waveguide member

Abstract

A waveguide member 100 comprises: a member 10 composed of a non-electroconductive material, the member 10 having an upper surface 11, a lower surface 12, a belt-form portion 14 that is dug from the lower surface 12 toward the upper surface 11 and has a first top surface 15 expanding in a belt-form shape, and a plurality of holes 16 that extend from the lower surface 12 toward the upper surface 11 and are arranged adjacent to at least part of the belt-form part 14, the plurality of holes 16 having a second top surface 17 and a side peripheral surface 18; and an electroconductive film 20 that covers at least the upper surface 11, the lower surface 12, the first top surface 15 of the belt-form portion 14, and the second top surface 17 and the side peripheral surface 18 of the plurality of holes 16 of the member 10.

Description

Waveguide member, waveguide device, and method for manufacturing a waveguide member

[0001] The present invention relates to a waveguide member, a waveguide device, and a method for manufacturing a waveguide member.

[0002] In recent years, research and development into millimeter-wave sensing and communications has expanded, necessitating the development of high-gain, low-loss, wideband, and multi-channel antennas. In response to this demand, WRG (Waffle Iron Ridge WaveGuide) technology, useful as a next-generation antenna and waveguide, has been developed (see, for example, Patent Documents 1 and 2). Figure 3 of Patent Document 1 discloses the basic structure of a WRG. Patent Document 2, as a subordinate structure, discloses a WRG structure for high-frequency bands such as millimeter waves, in which two conductive members constituting this basic structure are fixed outside the waveguide region. One of the features of the WRG technology is the formation of separation walls to prevent mutual coupling between adjacent waveguides in multiple waveguides within an antenna located from a millimeter-wave IC (Monolithic Microwave Integrated Circuit) to the antenna radiation hole for transmitting and receiving millimeter-wave electromagnetic waves. This prevents leakage of propagating electromagnetic waves, thereby maintaining transmission loss comparable to that of a metal waveguide and minimizing interference with electromagnetic waves transmitted through adjacent waveguides. In conventionally used microstrip waveguides and microstrip antennas, no such separating wall exists.

[0003] A major application of millimeter-wave antennas is imaging radar sensing, which has multiple transmit and receive channels. When a microstrip antenna is used for this purpose, in addition to the large loss in the waveguide, interference due to mutual coupling between adjacent waveguides and antenna radiating elements within the antenna can cause problems such as reduced target detection accuracy. On the other hand, when WRG technology is used for such multi-channel antennas, not only is the loss in the waveguide extremely low, but the mutual coupling between adjacent waveguides within the antenna is also significantly reduced. Furthermore, the use of antenna radiating holes suitable for WRG, such as mini-horn antennas and slot antennas, can further reduce mutual coupling. This ensures accurate signal transmission and reception between the antenna transmit and receive holes and the MMIC terminals that transmit and receive these signals. As a result, in millimeter-wave radar sensing, for example, the target signal contained in the received electromagnetic waves from the target can be accurately detected, enabling accurate target detection.

[0004] In WRG technology, this separation wall is realized by magnetic walls on both sides of the ridge waveguide, which are realized by periodic structures such as rod arrays. When this magnetic wall is realized with a single rod array, the isolation effect is expected to be approximately 30 dB. To further enhance this isolation effect, if two rod arrays are provided between the two ridge waveguides, the isolation effect is expected to be approximately 40 dB, achieving high isolation performance suitable for an array antenna. Such magnetic walls have a confinement function that stops the propagation of electromagnetic waves in the corresponding frequency band. The structures that constitute them are called artificial magnetic conductors (AMCs), and can be realized with structures other than rod arrays (see, for example, Patent Document 2). For example, the description in the middle of paragraph 0015 of Patent Document 2 that "The texture or structure is often periodic or quasi-periodic and is designed to interact with waves so as to behave macroscopically as an artificial magnetic conductor (AMC), an electromagnetic band gap (EBG) surface, or a soft surface" is helpful.

[0005] Patent Documents 3 and 4 disclose means for adjusting the characteristics of a ridge waveguide, which is a WRG waveguide, and provide means for adjusting the waveguide characteristics when used in a wide range of applications.

[0006] International Publication No. 03 / 065497 Special Publication No. 2011-527171 Special Publication No. 2018-511187 Japanese Patent Application Laid-Open No. 2017-130924

[0007] The basic structure of a WRG is a structure in which a first conductive member including, for example, a ridge or a rod array is assembled with a second conductive member constituting a top plate. In recent years, in response to the expansion of applications of WRG technology, there has been a demand for simple and inexpensive manufacturing of waveguide members and waveguide devices using WRG.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to simplify and reduce the cost of manufacturing a waveguide member and a waveguide device using WRG technology.

[0009] The present invention is a waveguide member comprising: a member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and extending in a band shape, and a plurality of hole portions extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of hole portions having a second top surface and a side peripheral surface; and a conductive film covering at least the upper surface of the member, the lower surface, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of hole portions.

[0010] The present invention is a waveguide member comprising: a first member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and extending in a band shape, and a plurality of hole portions extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of hole portions having a second top surface and a side peripheral surface; a conductive film covering at least the lower surface of the first member, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of hole portions; and a second member provided on the upper surface side of the first member, the second member having a conductive lower surface.

[0011] The present invention is a waveguide member comprising: a member made of a non-conductive material having an upper surface, a lower surface, a strip-shaped portion having a first top surface that is dug from the lower surface toward the upper surface and extends in a strip-like shape, and a plurality of holes that penetrate from the lower surface to the upper surface and are arranged adjacent to at least a portion of the strip-shaped portion; and a conductive film that covers all surfaces of the member.

[0012] The present invention provides a waveguide device comprising the waveguide member described above, in which a waveguide is formed between the conductive film provided on the first top surface and the conductive film provided on the upper surface, and an electromagnetic wave propagation barrier is formed by the conductive film provided in the plurality of hole portions.

[0013] The present invention is a waveguide device comprising the waveguide member described above, in which a waveguide is formed between the conductive film provided on the first top surface and the second member, and an electromagnetic wave propagation barrier is formed by the conductive film provided in the multiple hole portions.

[0014] The present invention provides a method for manufacturing a waveguide member, comprising the steps of: forming a member made of a non-conductive material, the member having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and extending in a band shape; and a plurality of hole portions extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of hole portions having a second top surface and a side peripheral surface; and forming a conductive film that covers at least the upper surface of the member, the lower surface, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of hole portions.

[0015] The present invention provides a method for manufacturing a waveguide member, the method comprising the steps of: forming a first member made of a non-conductive material, the first member having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and extending in a band shape; and a plurality of holes extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of holes having a second top surface and a side peripheral surface; forming a conductive film that covers at least the lower surface of the first member, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of holes; and forming a second member having a conductive lower surface on the upper surface side of the first member.

[0016] The present invention provides a method for manufacturing a waveguide member, comprising the steps of: forming a member made of a non-conductive material, the member having an upper surface, a lower surface, a band-shaped portion having a first top surface that is dug from the lower surface toward the upper surface and extends in a band shape; and a plurality of holes that penetrate from the lower surface to the upper surface and are arranged adjacent to at least a portion of the band-shaped portion; and forming a conductive film that covers all surfaces of the member.

[0017] According to the present invention, the waveguide member and the waveguide device can be manufactured easily and inexpensively using the WRG technology.

[0018] FIG. 1(a) is a plan view of a waveguide according to Example 1, FIG. 1(b) is a cross-sectional view taken along line A-A of FIG. 1(a), and FIG. 1(c) is a cross-sectional view of a waveguide device using the waveguide according to Example 1. FIGS. 2(a) and 2(c) are plan views showing a manufacturing method of the waveguide according to Example 1, and FIGS. 2(b) and 2(d) are cross-sectional views taken along line A-A of FIGS. 2(a) and 2(c). FIG. 3 is a cross-sectional view of a waveguide according to a modified example of Example 1 and a waveguide device using this waveguide. FIG. 4(a) is a cross-sectional view of a waveguide according to Example 2 and a waveguide device using this waveguide. FIG. 4(b) is a cross-sectional view of a waveguide according to a modified example of Example 2 and a waveguide device using this waveguide. FIG. 5(a) is a plan view of a waveguide member according to Example 3 and a waveguide device using this waveguide member, FIG. 5(b) is a cross-sectional view taken along line A-A of FIG. 5(a), and FIG. 5(c) is a cross-sectional view of a waveguide member according to a modified example of Example 3 and a waveguide device using this waveguide member. FIGS. 6(a) to 6(c) are cross-sectional views showing a manufacturing method of a waveguide member according to Example 3. FIG. 7(a) is a plan view of a waveguide member according to Example 4 and a waveguide device using this waveguide member, FIG. 7(b) is a cross-sectional view taken along line A-A of FIG. 7(a), and FIG. 7(c) is a cross-sectional view of a waveguide member according to a modified example of Example 4 and a waveguide device using this waveguide member. FIGS. 8(a) to 8(c) are cross-sectional views showing a manufacturing method of a waveguide member according to Example 4. FIG. 9(a) is a plan view of a waveguide member according to Example 5 and a waveguide device using this waveguide member, and FIG. 9(b) is a cross-sectional view taken along line A-A of FIG. 9(a). 10(a) and 10(b) are cross-sectional views showing a method for manufacturing a waveguide member according to Example 5. Fig. 11 is a block diagram showing a vehicle driving control device according to Example 6.

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] FIG. 1(a) is a plan view of a waveguide member 100 according to a first embodiment, and FIG. 1(b) is a cross-sectional view taken along line A-A of FIG. 1(a). FIG. 1(c) is a cross-sectional view of a waveguide device 600 using the waveguide member 100 according to the first embodiment. The thickness direction of the member 10 made of a non-conductive material is defined as the Z-axis direction. Directions perpendicular to the Z-axis direction and perpendicular to each other are defined as the X-axis direction and the Y-axis direction. Note that the terms "upper" and "lower" used in this specification and claims are used for convenience to make it easier to understand the explanation of the relative positions of objects, and do not limit the scope of the present invention.

[0021] 1( a) and 1(b), the waveguide member 100 includes a member 10 and a conductive film 20. The member 10 has an upper surface 11, a lower surface 12, four side surfaces 13 connecting the periphery of the upper surface 11 and the periphery of the lower surface 12, a strip-shaped portion 14 carved from the lower surface 12 toward the upper surface 11, and a plurality of holes 16 extending from the lower surface 12 toward the upper surface 11. The member 10 is formed of a resin material such as polyimide. In this specification, the term "upper surface" refers to a collection of surfaces that can be captured on the surface of the member 10 when the member 10, which is arranged along the XY plane, is viewed from the +Z-axis direction. The term "lower surface" is also used in the same sense.

[0022] The band-shaped portion 14 has a first top surface 15 that extends in a band shape and an inner surface 19 that connects to the first top surface 15. The band-shaped portion 14 extends in the Y-axis direction. The first top surface 15 and the upper surface 11 are surfaces that face each other, and the member 10 is present in a region 32 between the first top surface 15 and the upper surface 11. In this specification, the term "opposing surfaces" refers to surfaces that are within the field of view when viewing one surface from an observation point on the other surface in the Z-axis direction. At least a portion of the inner surface 19 of the band-shaped portion 14 may be tapered downward.

[0023] At least a portion of the plurality of holes 16 is disposed adjacent to the band-shaped portion 14. The hole 16 has a second top surface 17 and a side peripheral surface 18 connected to the second top surface 17. The second top surface 17 and the upper surface 11 are surfaces facing each other, and the member 10 is present in a region 42 between the second top surface 17 and the upper surface 11. The hole 16 has, for example, a rectangular shape when viewed from the Z-axis direction, but is not limited to this and may have other shapes such as a circle or an ellipse. Furthermore, at least a portion of the side peripheral surface 18 of the hole 16 may be tapered to widen downward.

[0024] The conductive film 20 covers the entire surface of the member 10. That is, the conductive film 20 covers the top surface 11, bottom surface 12, four side surfaces 13, the first top surface 15 and inner surface 19 of the band-shaped portion 14, and the second top surface 17 and side surface 18 of the hole 16. The band-shaped portion 14 and the hole 16 are hollow inside the conductive film 20. Instead of being hollow, at least a portion of the band-shaped portion 14 and the hole 16 may be covered or filled with a non-conductive material. The conductive film 20 is a conductive metal film containing, for example, copper or nickel. The conductive film 20 provided on the first top surface 15 of the band-shaped portion 14 and the conductive film 20 provided on the second top surface 17 of the hole 16 face the conductive film 20 provided on the top surface 11 of the member 10, with the member 10 sandwiched between them. The conductive film 20 provided on the inner surface 19 of the band-shaped portion 14 is in contact with the conductive film 20 provided on the first top surface 15 and the conductive film 20 provided on the bottom surface 12. Furthermore, the conductive film 20 provided on the side peripheral surface 18 of the hole 16 is in contact with the conductive film 20 provided on the second top surface 17 and the conductive film 20 provided on the bottom surface 12. "In contact" means that the conductive film 20 provided on the inner surface 19 or the side peripheral surface 18 is connected to the conductive film 20 provided on the first top surface 15 or the second top surface 17 and the conductive film 20 provided on the bottom surface 12 while maintaining electrical continuity with each other.

[0025] As described above, the waveguide member 100 has a structure in which the conductive film 20 is provided to cover the surface of a member 10 having a strip-shaped portion 14 carved from the lower surface 12 toward the upper surface 11 and a plurality of holes 16 extending from the lower surface 12 toward the upper surface 11. This structure can be manufactured easily and inexpensively by the method shown in Figures 2(a) to 2(d) described below. In particular, since the conductive film 20 covers the entire surface of the member 10, manufacturing becomes easier and more inexpensive.

[0026] 1C, in a waveguide device 600 using the waveguide member 100 according to the first embodiment, the conductive film 20 on the first top surface 15 forms a waveguide surface 30. The waveguide surface 30 faces the conductive film 20 on the top surface 11 across the member 10, and extends in the Y-axis direction along the strip portion 14. In a region 32 between the conductive film 20 on the first top surface 15 and the conductive film 20 on the top surface 11, a ridge waveguide 34 (WRG) through which electromagnetic waves propagate is formed.

[0027] By providing the conductive film 20 on the second top surface 17 and the side peripheral surface 18 of the plurality of holes 16 arranged adjacent to the strip portion 14, the holes 16 function as magnetic walls that suppress lateral leakage of electromagnetic waves propagating through the ridge waveguide 34. That is, the conductive film 20 of the holes 16 forms an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34. Here, "adjacent" refers to a state in which the holes 16 are arranged close to the strip portion 14 without any conductive object other than the conductive film 20 sandwiched therebetween, in a position that achieves the required function, i.e., the function of blocking electromagnetic waves when used as a magnetic wall. In such a case, the distance between adjacent conductive films 20 is, for example, λ ０ If the required functionality can be realized even at a distance greater than this, it is considered "adjacent." ０ is a representative value of the wavelength in free space of the electromagnetic wave propagating through the ridge waveguide 34 (for example, a wavelength corresponding to the center frequency of the band of use (operating frequency band)). The ridge waveguide 34 propagates electromagnetic waves in the microwave or millimeter wave band with low loss.

[0028] The various dimensions of the strip portion 14 and the hole 16 are determined by the wavelength of the electromagnetic wave propagating through the ridge waveguide 34. For example, the various dimensions of the waveguide member and conductive rod described in Patent Document 4 can be applied to the various dimensions of the strip portion 14 and the hole 16. The waveguide member in Patent Document 4 corresponds to the strip portion 14, and the conductive rod corresponds to the hole 16.

[0029] Since the waveguide member 100 can be manufactured simply and inexpensively as shown in FIGS. 2( a) to 2(d) described below, the waveguide device 600 can also be manufactured simply and inexpensively. Furthermore, since the ridge waveguide 34 is filled with the member 10, the wavelength of the electromagnetic waves propagating through the ridge waveguide 34 is shorter than when the ridge waveguide 34 is an air gap. Since the various dimensions of the strip portion 14 and the hole 16 are determined by the wavelength of the electromagnetic waves propagating through the ridge waveguide 34, the various dimensions of the strip portion 14 and the hole 16 are smaller. Therefore, the waveguide member 100 and the waveguide device 600 can be miniaturized. This may be particularly useful when electromagnetic waves in the terahertz band are propagating.

[0030] [Manufacturing Method] Figures 2(a) and 2(c) are plan views showing a manufacturing method of the waveguide member 100 according to Example 1, and Figures 2(b) and 2(d) are cross-sectional views taken along the line A-A in Figures 2(a) and 2(c). As shown in Figures 2(a) and 2(b), a member 10 is formed having a strip portion 14 carved from the lower surface 12 toward the upper surface 11, and a plurality of holes 16 extending from the lower surface 12 toward the upper surface 11 and arranged adjacent to at least a portion of the strip portion 14. The member 10 is formed, for example, by molding using a mold. Note that the member 10 may also be formed by forming the strip portion 14 and the holes 16 by cutting a rectangular parallelepiped member with a drill or the like.

[0031] 2(c) and 2(d), a conductive film 20 is formed to cover the entire surface of the member 10. The conductive film 20 is formed by, for example, electrolytic plating or electroless plating. The conductive film 20 is a conductive metal film containing, for example, copper, nickel, or the like. In this way, the waveguide member 100 according to the first embodiment is formed.

[0032] 3 is a cross-sectional view of a waveguide member 110 according to a modification of Example 1 and a waveguide device 610 using the waveguide member 110. As shown in FIG. 3, in this modification of Example 1, the conductive film 20 covers only the upper surface 11, the lower surface 12, the first top surface 15 of the strip portion 14, the second top surface 17 of the hole 16, and the side surface 18 of the member 10. Note that the conductive film 20 may not be provided on part of the side surface 18 of the hole 16, but at least the conductive film 20 on the second top surface 17 and the conductive film 20 on the lower surface 12 are in contact with each other. The other configurations are the same as those of Example 1, and therefore will not be described again.

[0033] The waveguide member 110 according to the modified example of Example 1 is manufactured by the same method as the waveguide member 100 according to Example 1, except that a mask layer is formed on the side surfaces 13 of the member 10 on which the conductive film 20 is not formed and on the inner surfaces 19 of the strip portions 14, and then the conductive film 20 is formed by electrolytic plating or electroless plating, and then the mask layer is removed. Therefore, the waveguide member 110 according to the modified example of Example 1 can also be manufactured simply and inexpensively.

[0034] In a waveguide device 610 using a waveguide member 110 according to a modification of the first embodiment, similar to the waveguide device 600 according to the first embodiment, the conductive film 20 on the first top surface 15 forms a waveguide surface 30, and a ridge waveguide 34 is formed in a region 32 between the conductive film 20 on the first top surface 15 and the conductive film 20 on the upper surface 11. The conductive film 20 in the multiple holes 16 forms an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34. Since the waveguide member 110 according to the modification of the first embodiment can be manufactured simply and inexpensively, the waveguide device 610 can also be manufactured simply and inexpensively. Furthermore, since the ridge waveguide 34 is filled with the member 10, the waveguide device 610 can be miniaturized, similar to the first embodiment.

[0035] 4A is a cross-sectional view of a waveguide member 200 according to a second embodiment and a waveguide device 700 using the waveguide member 200. As shown in FIG. 4A , in the second embodiment, the member 10 includes a first portion 10a forming the lower surface 12 and a second portion 10b having a different dielectric constant from that of the first portion 10a and forming the upper surface 11. The second portion 10b is located in at least a portion of a region 32 between a first top surface 15 of the strip portion 14 and the upper surface 11 of the member 10, and in at least a portion of a region 42 between a second top surface 17 of the hole portion 16 and the upper surface 11 of the member 10. For example, the first portion 10a is formed of polyimide, and the second portion 10b is formed of benzocyclobutene (BCB) or syndiotactic polystyrene (SPS). In the region 32, the thickness of the second portion 10b may be thicker than that of the first portion 10a, for example, 1.2 times or more, 1.5 times or more, or 2.0 times or more. The other configurations are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0036] The waveguide member 200 according to the second embodiment is manufactured by the same method as the waveguide member 100 according to the first embodiment shown in Figures 2(a) to 2(d), except that a member 10 having a first portion 10a forming the lower surface 12 and a second portion 10b having a different dielectric constant from that of the first portion 10a and forming the upper surface 11 is formed, for example, by molding. Therefore, the waveguide member 200 according to the second embodiment can also be manufactured simply and inexpensively. Furthermore, a waveguide device 700 using the waveguide member 200 can also be manufactured simply and inexpensively.

[0037] 4B is a cross-sectional view of a waveguide member 210 according to a modified example of Example 2 and a waveguide device 710 using the waveguide member 210. As shown in FIG. 4B, in the modified example of Example 2, the conductive film 20 covers only the upper surface 11, the lower surface 12, the first top surface 15 of the strip portion 14, the second top surface 17 of the hole portion 16, and the side circumferential surface 18 of the member 10. The other configurations are the same as those of Example 2, and therefore will not be described again.

[0038] The waveguide member 210 according to the modified example of Example 2 is manufactured by the same method as the waveguide member 200 according to Example 2, except that a mask layer is formed on the side surface 13 of the member 10 on which the conductive film 20 is not formed and on the inner surface 19 of the strip portion 14, and then the conductive film 20 is formed using electrolytic plating or electroless plating, and the mask layer is then removed. Therefore, the waveguide member 210 according to the modified example of Example 2 can also be manufactured simply and inexpensively. Furthermore, the waveguide device 710 using the waveguide member 210 can also be manufactured simply and inexpensively.

[0039] 4( a) and 4(b), in waveguide devices 700 and 710 using the waveguide members according to the second embodiment and the modified example of the second embodiment, the conductive film 20 on the first top surface 15 forms a waveguide surface 30, and a ridge waveguide 34 is formed in a region 32 between the conductive film 20 on the first top surface 15 and the conductive film 20 on the upper surface 11. The conductive film 20 in the multiple holes 16 forms an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34.

[0040] For example, at the center frequency of the operating frequency band, the dielectric loss tangent tan δ of the second portion 10 b is smaller than the dielectric loss tangent tan δ of the first portion 10 a. By positioning the second portion 10 b having such a small dielectric loss tangent tan δ at least partially between the first top surface 15 of the strip-shaped portion 14 and the upper surface 11 of the member 10, the loss of the electromagnetic wave propagating through the ridge waveguide 34 can be reduced compared to when the member 10 is entirely formed of the first portion 10 a.

[0041] For example, at the center frequency of the operating frequency band, the dielectric constant of the first portion 10a is greater than that of the second portion 10b. By providing the first portion 10a with such a large dielectric constant around the strip portion 14, the dimensions of the strip portion 14 and the hole 16 are smaller than when the member 10 is formed entirely of the second portion 10b. This allows the waveguide member and the waveguide device to be miniaturized.

[0042] From the viewpoint of reducing electromagnetic wave loss, the dielectric loss tangent tanδ of the second portion 10b is preferably 0.9 times or less, more preferably 0.8 times or less, and even more preferably 0.7 times or less, the dielectric loss tangent tanδ of the first portion 10a at the center frequency of the operating frequency band. From the viewpoint of miniaturization, the relative dielectric constant of the first portion 10a is preferably 1.1 times or more, more preferably 1.2 times or more, and even more preferably 1.3 times or more, the relative dielectric constant of the second portion 10b at the center frequency of the operating frequency band. Note that materials with a large dielectric loss tangent tanδ tend to have a large relative dielectric constant.

[0043] FIG. 5( a ) is a plan view of a waveguide member 300 according to a third embodiment and a waveguide device 800 using the waveguide member 300, and FIG. 5( b ) is a cross-sectional view taken along the line A-A in FIG. 5( a ). FIG. 5( c ) is a cross-sectional view of a waveguide member 310 according to a modified example of the third embodiment and a waveguide device 810 using the waveguide member 310. For clarity, FIG. 5( a ) only illustrates a member 50 and spacers 52. As shown in FIGS. 5( a ) and 5( b ), in the third embodiment, a conductive film 20 is not provided on the upper surface 11 of the member 10 (first member). A member 50 (second member) is provided on the upper surface 11 side via a plurality of spacers 52. In this specification, the term “upper surface side” means “above, including the upper surface.” The spacers 52 are provided on the periphery of the upper surface 11 of the member 10 and positioned so as not to overlap with the strip portion 14 when viewed from the +Z-axis direction. The spacers 52 are formed of metal, resin, ceramic, or the like. The spacer 52 may be formed from the same material as the member 10. At least the lower surface 51 of the member 50 is conductive. The member 50 may be a member formed by processing such as molding or cutting a conductive metal, or may have a structure in which a conductive film such as a metal film is formed on the surface of an insulating member such as resin by plating, painting, or surface treatment. The member 10 and a gap 54 are present in a region 32 between the first top surface 15 of the strip portion 14 and the conductive lower surface 51 of the member 50. The member 10 and a gap 54 are also present in a region 42 between the second top surface 17 of the multiple hole portions 16 and the conductive lower surface 51 of the member 50. The other configurations are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0044] 5(c), in the modified example of Example 3, the conductive film 20 covers only the lower surface 12 of the surface of the member 10, the first top surface 15 of the strip portion 14, the second top surface 17 of the hole portion 16, and the side circumferential surface 18. The other configurations are the same as those of Example 3, and therefore will not be described again.

[0045] 5(b) and 5(c), in waveguide devices 800 and 810 using the waveguide member according to Example 3 and the modified example of Example 3, the conductive film 20 on the first top surface 15 forms a waveguide surface 30, and a ridge waveguide 34 made up of the member 10 and a gap 54 is formed in a region 32 between the conductive film 20 on the first top surface 15 and the conductive film 20 on the upper surface 11. The conductive film 20 in the multiple holes 16 forms an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34.

[0046] 6( a) to 6(c) are cross-sectional views showing a manufacturing method of a waveguide member 300 according to Example 3. As shown in Fig. 6(a), a member 10 is formed having a strip-shaped portion 14 carved from the lower surface 12 toward the upper surface 11 and a plurality of holes 16 extending from the lower surface 12 toward the upper surface 11. The member 10 may be formed by molding using a mold, as in Example 1, or may be formed by cutting a rectangular parallelepiped member with a drill or the like.

[0047] 6(b), after forming a mask layer 60 on the upper surface 11, the conductive film 20 is formed by electrolytic plating or electroless plating using the mask layer 60 as a mask. This forms the conductive film 20 that covers the entire surface of the member 10 except for the upper surface 11. The mask layer 60 is formed from, for example, a resist.

[0048] 6C, after removing the mask layer 60, the member 50 is disposed on the upper surface 11 side of the member 10 via a plurality of spacers 52. This forms the waveguide member 300 according to Example 3. The spacers 52 may be formed by disposing a member made of a different material from the member 10 on the upper surface 11 side, or may be formed by integral molding that is made of the same material as the member 10 and realizes a continuous structure with the member 10.

[0049] The waveguide member 310 according to the modified example of Example 3 is manufactured by the same method as the waveguide member 300 according to Example 3, except that a mask layer is formed on the upper surface 11, the side surface 13, and the inner surface 19 of the strip portion 14 of the member 10 on which the conductive film 20 is not formed, and then the conductive film 20 is formed by electroplating or electroless plating, and then the mask layer is removed.

[0050] As described above, the waveguide members 300 and 310 according to the third embodiment and its modifications can be manufactured easily and inexpensively. Therefore, the waveguide devices 800 and 810 using the waveguide members according to the third embodiment and its modifications can also be manufactured easily and inexpensively. In particular, when the conductive film 20 covers all surfaces of the member 10 except for the upper surface 11, the manufacturing process can be more easily and inexpensively performed.

[0051] Furthermore, the conductive film 20 is not provided on the top surface 11 of the member 10, and the member 50 is provided on the top surface 11 side via a plurality of spacers 52. As a result, a gap 54 made of, for example, air is formed in the region 32 between the first top surface 15 of the member 10, where the ridge waveguide 34 is formed, and the bottom surface 51 of the member 50. Because the dielectric loss of air is smaller than the dielectric loss of resin, etc., it is possible to reduce the loss of electromagnetic waves propagating through the ridge waveguide 34. Furthermore, because the member 10 is provided around the strip portion 14, the various dimensions of the strip portion 14 and the hole 16 are reduced, allowing the waveguide member and waveguide device to be miniaturized.

[0052] FIG. 7( a) is a plan view of a waveguide member 400 according to a fourth embodiment and a waveguide device 900 using the waveguide member 400, and FIG. 7( b) is a cross-sectional view taken along the line A-A in FIG. 7( a). FIG. 7( c) is a cross-sectional view of a waveguide member 410 according to a modified example of the fourth embodiment and a waveguide device 910 using the waveguide member 410. For clarity, FIG. 7( a) only illustrates the member 10, the recess 72, and the member 70. As shown in FIGS. 7( a) and 7( b), in the fourth embodiment, the member 10 (first member) has a recess 72 on its upper surface 11. The recess 72 is positioned at least opposite the first top surface 15 of the strip portion 14 and extends in the Y-axis direction. The conductive film 20 is not provided on the upper surface 11. A member 70 (second member) covering the recess 72 is provided on the upper surface 11. The member 70 extends in the Y-axis direction and completely covers the recess 72. At least the lower surface 71 of the member 70 is conductive. The member 70 may be a member formed by processing such as molding or cutting a conductive metal, or may have a structure in which a conductive film such as a metal film is formed on the surface of an insulating member such as resin by plating, painting, or surface treatment. A member 10 and a void 74 are present in a region 32 between the first top surface 15 of the band-shaped portion 14 and the conductive lower surface 71 of the member 70. The multiple holes 16 are present in a region 42 between the second top surface 17 and the conductive lower surface 71 of the member 70, where a member 10 and a void 54 are present and a region in which only the member 10 is present. The other configurations are the same as those of the first embodiment, and a description thereof will be omitted.

[0053] 7(c), in the modification of Example 4, the conductive film 20 covers only the lower surface 12 of the surface of the member 10, the first top surface 15 of the strip portion 14, the second top surface 17 of the hole portion 16, and the side circumferential surface 18. The other configurations are the same as those of Example 4, and therefore will not be described again.

[0054] 7(b) and 7(c), in waveguide devices 900 and 910 using the waveguide members according to the fourth embodiment and the modified example of the fourth embodiment, the conductive film 20 on the first top surface 15 forms a waveguide surface 30, and a ridge waveguide 34 made up of the member 10 and a gap 74 is formed in a region 32 between the conductive film 20 on the first top surface 15 and the member 70. The conductive film 20 in the multiple holes 16 forms an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34.

[0055] 8( a) to 8(c) are cross-sectional views showing a method for manufacturing a waveguide member 400 according to Example 4. As shown in Fig. 8(a), a member 10 is formed having a strip portion 14 carved from the lower surface 12 toward the upper surface 11, a plurality of holes 16 extending from the lower surface 12 toward the upper surface 11, and a recess 72 provided on the upper surface 11 so as to face the strip portion 14. As in Example 1, the member 10 may be formed by molding using a mold, or may be formed by cutting a rectangular parallelepiped member with a drill or the like.

[0056] 8(b), after forming a mask layer 60 on the upper surface 11 and the recessed portion 72, the conductive film 20 is formed by electrolytic plating or electroless plating using the mask layer 60 as a mask. This forms the conductive film 20 that covers the entire surface of the member 10 except for the upper surface 11 and the recessed portion 72. The mask layer 60 is formed from, for example, a resist.

[0057] 8C, after removing the mask layer 60, a member 70 is placed on the upper surface 11 of the member 10 to cover the recess 72. In this way, the waveguide member 400 according to the fourth embodiment is formed.

[0058] The waveguide member 410 according to the modified example of Example 4 is manufactured by the same method as the waveguide member 400 according to Example 4, except that a mask layer is formed on the upper surface 11, the recess 72, the side surface 13, and the inner surface 19 of the strip portion 14 of the member 10 on which the conductive film 20 is not formed, and then the conductive film 20 is formed by electroplating or electroless plating, and then the mask layer is removed.

[0059] As described above, the waveguide members 400 and 410 according to the fourth embodiment and its modifications can be manufactured easily and inexpensively. Therefore, the waveguide devices 900 and 910 using the waveguide members according to the fourth embodiment and its modifications can also be manufactured easily and inexpensively. In particular, when the conductive film 20 covers the entire surface of the member 10 except for the upper surface 11 and the recessed portion 72, the manufacturing process can be more easily and inexpensively performed.

[0060] Furthermore, a recess 72 is formed on the upper surface 11 of the member 10 at a position corresponding to at least the first top surface 15 of the strip-shaped portion 14, and the member 70 is provided to cover the recess 72. As a result, a gap 74 is formed in the region 32 between the first top surface 15 of the member 10, where the ridge waveguide 34 is formed, and the lower surface 71 of the member 70. This reduces the loss of electromagnetic waves propagating through the ridge waveguide 34. Furthermore, because the member 10 is provided around the strip-shaped portion 14, the various dimensions of the strip-shaped portion 14 and the hole 16 are reduced, allowing the waveguide member and waveguide device to be miniaturized.

[0061] Fig. 9(a) is a plan view of a waveguide member 500 according to Example 5 and a waveguide device 1000 using the waveguide member 500, and Fig. 9(b) is a cross-sectional view taken along the line A-A in Fig. 9(a). As shown in Fig. 9(a) and Fig. 9(b), in Example 5, a hole 16 formed in a member 10 penetrates from the lower surface 12 to the upper surface 11 and has a circular shape when viewed from the Z-axis direction. The other configurations are the same as those of Example 1, and therefore a description thereof will be omitted.

[0062] In a waveguide device 1000 using the waveguide member according to the fifth embodiment, the conductive film 20 on the first top surface 15 forms a waveguide surface 30, and a ridge waveguide 34 is formed in a region 32 between the conductive film 20 on the first top surface 15 and the conductive film 20 on the upper surface 11. The conductive film 20 in the plurality of holes 16 functions as an electric wall, and an electromagnetic wave propagation barrier 36 that suppresses leakage of electromagnetic waves propagating through the ridge waveguide 34 is formed.

[0063] 10( a) and 10(b) are cross-sectional views showing a method for manufacturing a waveguide member 500 according to Example 5. As shown in Fig. 10(a), a member 10 is formed having a strip-shaped portion 14 carved from the lower surface 12 toward the upper surface 11 and a plurality of holes 16 penetrating from the lower surface 12 to the upper surface 11. The member 10 may be formed by molding using a mold, as in Example 1, or may be formed by cutting a rectangular parallelepiped member with a drill or the like.

[0064] 10B, a conductive film 20 is formed to cover the entire surface of the member 10. The conductive film 20 is formed by, for example, electrolytic plating or electroless plating. In this manner, the waveguide member 500 according to the fifth embodiment is formed.

[0065] In this way, the waveguide member 500 according to Example 5 can be manufactured easily and inexpensively. Therefore, the waveguide device 1000 using the waveguide member according to Example 5 can also be manufactured easily and inexpensively. Furthermore, since the member 10 is provided around the belt-like portion 14, the various dimensions of the belt-like portion 14 and the hole portion 16 are reduced, and the waveguide member and the waveguide device can be made smaller.

[0066] FIG. 11 is a block diagram illustrating a vehicle driving control device 1200 according to a sixth embodiment. As illustrated in FIG. 11 , the vehicle driving control device 1200 includes a radar system 80 and a driving assistance electronic control device 86 connected to the radar system 80. The radar system 80 includes an array antenna 81 and a radar signal processing device 82. The array antenna 81 is capable of emitting high-frequency millimeter waves. The array antenna 81 includes a plurality of antenna elements 83 and a waveguide device 600 connected to the antenna elements 83. The antenna elements 83 output received signals to the waveguide device 600 in response to one or more incoming waves. The array antenna 81 is attached to the vehicle. At least some of the functions of the radar signal processing device 82 may be implemented by a computer 90 and a database 92 external to the vehicle driving control device 1200. The database 92 stores programs defining various signal processing algorithms. Data and program contents required for operation of the radar system 80 are updated externally via a communication device 87.

[0067] The radar signal processing device 82 has a signal processing circuit 84. The signal processing circuit 84 receives a received signal from the array antenna 81 and inputs the received signal or a secondary signal generated from the received signal to an arriving wave estimation unit 85. The signal processing circuit 84 is configured to perform calculations using the received signal or the secondary signal and output a signal indicating the number of arriving waves. The signal indicating the number of arriving waves is a signal indicating the number of one or more preceding vehicles traveling ahead of the host vehicle.

[0068] The incoming wave estimation unit 85 estimates an angle indicating the direction of the incoming wave and outputs a signal indicating the estimation result. The signal processing circuit 84 estimates the distance to the target that is the source of the incoming wave, the relative speed of the target, and the direction of the target using a known algorithm executed by the incoming wave estimation unit 85, and outputs a signal indicating the estimation result.

[0069] The driving assistance electronic control device 86 is configured to provide driving assistance for the vehicle based on various signals output from the radar signal processing device 82. For example, the driving assistance electronic control device 86 issues instructions to various electronic control units to perform functions such as issuing an alarm to prompt the driver to apply the brakes when the inter-vehicle distance becomes shorter than a set value, controlling the brakes, and controlling the accelerator.

[0070] 11 shows an example in which the waveguide device 600 in the first embodiment is provided, but the waveguide devices described in any of the modifications of the first embodiment to the fifth embodiment may also be provided. The waveguide device is not limited to being used in a radar system such as a millimeter wave radar system, but may also be used in other devices.

[0071] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

[0072] 10...member, 10a...first portion, 10b...second portion, 11...upper surface, 12...lower surface, 13...side surface, 14...band-shaped portion, 15...first top surface, 16...hole portion, 17...second top surface, 18...side peripheral surface, 19...inner surface, 20...conductive film, 30...waveguide surface, 32...region, 34...ridge waveguide, 36...electromagnetic wave propagation barrier, 42...region, 50...member, 51...lower surface, 52...spacer, 54...gap, 60...mask layer, 70...member, 71...lower surface, 72...recess, 74...gap, 80...radar system Array antenna, 81, radar signal processing device, 82, radar signal processing device, 83, antenna element, 84, signal processing circuit, 85, incoming wave estimation unit, 86, driving assistance electronic control device, 87, communication device, 90, computer, 92, database, 100, 110, 200, 210, 300, 310, 400, 410, 500, waveguide member, 600, 610, 700, 710, 800, 810, 900, 910, 1000, waveguide device, 1200, vehicle driving control device

Claims

1. A waveguide member comprising: a member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and spreading out in a band shape, and a plurality of holes extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of holes having a second top surface and a side peripheral surface; and a conductive film covering at least the upper surface, the lower surface, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of holes of the member.

2. A waveguide member as claimed in claim 1, said member having a first portion forming said lower surface, and a second portion forming said upper surface and having a dielectric constant different from that of said first portion, said second portion being located at least partially between said first top surface of said strip portion and said upper surface.

3. A waveguide member according to claim 1 or 2, wherein the conductive film covers all surfaces of the member.

4. A waveguide member comprising: a first member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and spreading in a band shape, and a plurality of holes extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of holes having a second top surface and a side peripheral surface; a conductive film covering at least the lower surface of the first member, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of holes; and a second member provided on the upper surface side of the first member, the lower surface of which is conductive.

5. The waveguide member according to claim 4, wherein the second member is provided on the upper surface side of the first member via a plurality of spacers.

6. A waveguide member according to claim 5, wherein said conductive film covers all surfaces of said first member except said top surface.

7. A waveguide member as described in claim 4, wherein the first member has a recess provided on the upper surface and positioned at least opposite the first top surface of the band-shaped portion, and the second member is provided on the upper surface of the first member, covering the recess.

8. A waveguide member according to claim 7, wherein said conductive film covers all surfaces of said first member except for said top surface and said recess.

9. A waveguide member comprising: a member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface that is dug from the lower surface toward the upper surface and extends in a band shape, and a plurality of holes that penetrate from the lower surface to the upper surface and are positioned adjacent to at least a portion of the band-shaped portion; and a conductive film that covers all surfaces of the member.

10. A waveguide device comprising the waveguide member according to claim 1 or 9, wherein a waveguide is formed between the conductive film provided on the first top surface and the conductive film provided on the upper surface, and an electromagnetic wave propagation barrier is formed by the conductive film provided in the multiple holes.

11. A waveguide device comprising the waveguide member according to claim 4, wherein a waveguide is formed between the conductive film provided on the first top surface and the second member, and an electromagnetic wave propagation barrier is formed by the conductive film provided in the multiple holes.

12. A method for manufacturing a waveguide member, comprising: a step of forming a member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and spreading in a band shape, and a plurality of holes extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of holes having a second top surface and a side peripheral surface; and a step of forming a conductive film covering at least the upper surface, the lower surface, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of holes of the member.

13. A method for manufacturing a waveguide member as described in claim 12, wherein the step of forming the member forms the member having a first portion forming the lower surface, and a second portion having a dielectric constant different from that of the first portion forming the upper surface, and located at least partially between the first top surface and the upper surface.

14. The method for producing a waveguide member according to claim 12 or 13, wherein the step of forming the conductive film forms the conductive film to cover the entire surface of the member.

15. A method for manufacturing a waveguide member, comprising the steps of: forming a first member made of a non-conductive material, the first member having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and spreading in a band shape, and a plurality of holes extending from the lower surface toward the upper surface and arranged adjacent to at least a portion of the band-shaped portion, the plurality of holes having a second top surface and a side peripheral surface; forming a conductive film covering at least the lower surface of the first member, the first top surface of the band-shaped portion, and the second top surfaces and the side peripheral surfaces of the plurality of holes; and forming a second member having a conductive lower surface on the upper surface side of the first member.

16. The method for manufacturing a waveguide member according to claim 15, wherein the step of forming the second member comprises forming the second member on the upper surface side of the first member via a plurality of spacers.

17. The method for manufacturing a waveguide member according to claim 16, wherein the step of forming a conductive film forms the conductive film to cover all surfaces of the first member except for the upper surface.

18. A method for manufacturing a waveguide member as described in claim 15, wherein the step of forming the first member forms the first member having a recess on its upper surface that is positioned at least opposite the first top surface of the band-shaped portion, and the step of forming the second member forms the second member on the upper surface of the first member so as to cover the recess.

19. The method for manufacturing a waveguide member according to claim 18, wherein the step of forming a conductive film forms the conductive film to cover all surfaces of the first member except for the upper surface and the recess.

20. A method for manufacturing a waveguide member, comprising the steps of: forming a member made of a non-conductive material having an upper surface, a lower surface, a band-shaped portion having a first top surface dug from the lower surface toward the upper surface and extending in a band shape, and a plurality of holes penetrating from the lower surface to the upper surface and positioned adjacent to at least a portion of the band-shaped portion; and forming a conductive film covering all surfaces of the member.

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