Slot antenna and method for manufacturing the same
The slot antenna design with parallel antenna plates and a central and peripheral conductor structure addresses the challenge of achieving omnidirectional antennas at subterahertz frequencies, offering improved manufacturing simplicity and reduced losses.
Patent Information
- Application Number
- JP2023178696
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-10-17
- Publication Date
- 2025-04-30
AI Technical Summary
Current technologies have not successfully realized an omnidirectional antenna using horizontal polarization for subterahertz frequencies, as existing designs become bidirectional and difficult to manufacture at higher frequencies.
A slot antenna with a simple structure, featuring two parallel antenna plates with a central conductor and peripheral conductor portions, is designed to achieve omnidirectionality by combining radiation from both sides of a single waveguide, utilizing a low loss waveguide system at frequencies above the millimeter wave band.
This design effectively achieves omnidirectionality with improved manufacturing simplicity and reduced losses, even at frequencies with short wavelengths, by widening the base plate and bringing the radiating surface spacing closer.
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Abstract
Description
[Technical field]
[0001] The present invention relates to a slot antenna and a method for manufacturing a slot antenna. [Background technology]
[0002] 5G and 6G will use the millimeter wave and sub-terahertz bands. At frequencies above the millimeter wave band, such as the millimeter wave and sub-terahertz bands, coaxial lines have large losses. For this reason, it is considered to use waveguide lines. Waveguide-based antennas include aperture antennas such as horn antennas and waveguide slot antennas, all of which are unidirectional. For example, a waveguide slot antenna radiates with a single directivity in the slot direction by cutting a slot in the waveguide (Patent Document 1). As an omnidirectional antenna, that is, an antenna with omni-directional characteristics, a configuration in which radio waves emitted from a horn antenna with TM01 excitation are reflected by a conical reflector to obtain vertical polarization is considered. Also, as an omni-directional antenna, there is a collinear antenna in which dipole antennas or patch antennas are arranged in series and fed in phase. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2007-59959 A [Non-patent literature]
[0004] [Non-Patent Document 1] "300 GHz Band Reflector Omnidirectional Antenna Using Cavity-Backed TM01 Mode Converter" Keisuke Sato, Ryuichi Sasaki, Shunta Ichikawa, Ichiro Oshima, IEICE Transactions on Electronics, Information and Communication Engineers (IEICE) Journal B, Vol. J105-B, No. 4, pp. 405-413, April 1, 2022 Summary of the Invention [Problem to be solved by the invention]
[0005] An omnidirectional antenna using horizontally polarized waves has not yet been realized in the sub-terahertz band. For example, a three-dimensional structure such as that described in Patent Document 1 is difficult to process at frequencies above the millimeter wave band because the antenna itself becomes small, and moreover the antenna becomes bidirectional rather than omnidirectional. Therefore, an object of the present invention is to realize an omni-directional antenna with a simple configuration in a waveguide antenna for the millimeter wave band or higher. Other objects of the present invention are also described in the detailed description of the invention. [Means for solving the problem]
[0006] The slot antenna according to claim 1 of the present invention is A slot antenna having omni-directional characteristics, It has two antenna plates arranged parallel to each other, The antenna plate has an antenna portion and a peripheral portion, The antenna part is A central conductor portion is provided. The central conductor portion has a slot, The peripheral portion is a slot antenna having a peripheral conductor portion formed to surround the antenna portion. This configuration is simple and therefore easy to manufacture. A slot antenna according to claim 2 of the present invention is the slot antenna according to claim 1, in which the frequency of the radiated radio waves is equal to or higher than the millimeter wave band. With the above-described configuration, the present invention makes it possible to obtain omni-directivity with a low-loss waveguide antenna at short wavelength frequencies such as the millimeter wave band or higher. A slot antenna according to claim 3 of the present invention is the slot antenna according to claim 2, wherein the central conductor portion and the peripheral conductor portion are formed from a single metal plate. The slot antenna according to claim 4 of the present invention is an inner plate having substantially the same size as the antenna plates is disposed between the two antenna plates arranged in parallel to each other; 4. The slot antenna according to claim 3, wherein the inner plate is formed from a metal plate. A slot antenna according to claim 5 of the present invention is the slot antenna according to claim 2, wherein the two antenna plates arranged parallel to each other are formed from metal plates of approximately the same shape. A slot antenna according to claim 6 of the present invention is the slot antenna according to claim 2, in which the two antenna plates are formed as one waveguide. Since slots are provided on both sides of a single waveguide, there is no need to add a distribution circuit, etc., compared to when two or more waveguides are combined back-to-back, making it possible to simplify the configuration. A slot antenna according to claim 7 of the present invention is the slot antenna according to claim 2, in which the antenna plate is formed from a substrate having a dielectric portion and a metal portion. With this configuration, omni-directionality can be obtained by forming it on SIW without multi-layering. The slot antenna of claim 8 of the present invention is a slot antenna described in any of claims 1 to 7, in which the width WO of the peripheral conductor portions formed on both sides of the center conductor portion is greater than or equal to the width WC of the center conductor portion. With this configuration, by making the width WO of the peripheral conductor portion equal to or greater than the width WC of the central conductor portion and widening the ground plane conductor, beam splitting can be reduced and even better omni-directional characteristics can be obtained. A slot antenna according to a ninth aspect of the present invention is the slot antenna according to any one of the first to seventh aspects, in which the distance between the two antenna plates arranged parallel to each other is 2 mm or less. By bringing the radiating surfaces closer together, even better omni-directional characteristics can be obtained. The slot antenna according to claim 10 of the present invention is the slot antenna according to any one of claims 1 to 7, wherein the cross section has a shape of a substantially rectangular parallelepiped having four corners that are cut into substantially triangular shapes. This configuration improves the characteristics of the antenna. A slot antenna according to an eleventh aspect of the present invention is the slot antenna according to any one of the third to fifth aspects, in which the metal plates are joined together by diffusion bonding. This configuration allows for inexpensive manufacturing by diffusion bonding. A method for manufacturing a slot antenna according to claim 12 of the present invention comprises the steps of: A method for manufacturing an omnidirectional slot antenna, comprising the steps of: The slot antenna is It has two antenna plates arranged parallel to each other, The antenna plate has an antenna portion and a peripheral portion, The antenna part is A central conductor portion is provided. The central conductor portion has a slot, The peripheral portion has a peripheral conductor portion formed to surround the antenna portion, an antenna plate forming step of forming the central conductor portion and the peripheral conductor portion from a single metal plate; This is a method for manufacturing a slot antenna, which includes a metal plate joining step of joining metal plates together. This configuration is simple and therefore easy to manufacture. A method for manufacturing a slot antenna according to claim 13 of the present invention is the method for manufacturing a slot antenna according to claim 12, wherein the metal plate joining step of joining the metal plates together is a step of joining the metal plates by diffusion bonding. This configuration allows for inexpensive manufacturing by diffusion bonding. A slot antenna according to claim 14 of the present invention is a manufacturing method for a slot antenna as described in claim 12, further comprising a cutting step of cutting off the four corners of the approximately rectangular parallelepiped cross section into approximately triangular shapes. This configuration improves the characteristics of the antenna. The slot antenna of claim 15 of the present invention is a manufacturing method for a slot antenna described in any of claims 12 to 14, wherein the antenna plate forming step of forming the center conductor portion and the peripheral conductor portion from a single metal plate includes a slot forming step of forming a slot by etching. Other advantages of the present invention will be described in the detailed description of the invention. [Brief description of the drawings]
[0007] [Figure 1] 1 shows an example of the configuration of a slot antenna in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] Omni-directionality is achieved by providing slots on both the front and back sides of the waveguide slot array antenna. By shortening the distance between the radiating surfaces and widening the base plate width, omnidirectional characteristics are obtained. The ground plane conductor is made wider to reduce deviation in the horizontal plane. Omnidirectional slot antenna on a waveguide.
[0009] 1 to 3 show an example of the configuration of a slot antenna 1 in one embodiment of the present invention. In the following description, the slot antenna may be referred to as a slot array antenna. The slot antenna 1 in this embodiment is an omni-directional slot antenna 1, and has two antenna plates 100 arranged parallel to each other. The antenna plate 100 has an antenna portion 110 and a peripheral portion 120 .
[0010] The antenna portion 110 has a central conductor portion 111 . The central conductor portion 111 has slots, and in this embodiment has eight slots 112 to 119. The peripheral portion 120 has a peripheral conductor portion 121 formed to surround the antenna portion 110 . With the above configuration, slots are cut on both the front and back of a single waveguide, and omni-directionality can be obtained by combining radiation in two directions.
[0011] In this embodiment, the two antenna plates 100 are formed as one waveguide, but other configurations are also possible, as will be described later. When combining two or more waveguides back to back to obtain omnidirectional characteristics by combining their directivities, it is necessary to add a distribution circuit, etc., which makes the structure complicated. However, in this configuration in which two antenna plates 100 are formed as a single waveguide, slots are provided on both sides of a single waveguide to obtain omnidirectional characteristics, thereby simplifying the configuration.
[0012] In one embodiment of the present invention, the slot antenna 1 radiates radio waves having a frequency equal to or higher than the millimeter wave band. With this configuration, it is possible to obtain omni-directionality with a low-loss waveguide antenna. Conventional three-dimensional structures are extremely difficult to manufacture at short wavelength frequencies such as the millimeter wave band or faster, but this structure is simple and therefore easy to manufacture.
[0013] In one embodiment of the present invention, two antenna plates 100 arranged parallel to each other are formed from metal plates of approximately the same shape.
[0014] In this embodiment, the width WO of the peripheral conductor parts 121 formed on both sides of the center conductor part 111 is equal to or greater than the width WC of the center conductor part 111. Increasing the width of the ground plane improves the omnidirectional characteristics. In other words, by widening the width of the ground plane on the slot surface, the element directivity from the front and back slots is expanded, and excellent omnidirectional characteristics can be obtained by combining radiation in two directions. If WO is equal to or greater than WC, an effect can be obtained even if it is 1 or 1.5 times WC, but better omni-directionality can be obtained by making WO about 2 times WC or more, such as about 5 times WC, as in this embodiment.
[0015] In one embodiment of the present invention, the slot antenna may have two antenna plates arranged parallel to each other with a distance of 2 mm or less. By bringing the radiating surfaces closer together, even better omni-directional characteristics can be obtained.
[0016] 4 and 5 show examples of the configuration of the slot antenna 1 in one embodiment of the present invention. In the above embodiment, the central conductor portion 111 and the peripheral conductor portion 121 are formed from a single metal plate 130. The slot antenna 1 has one slot 112. In this embodiment, the central conductor portion 111 and the peripheral conductor portion 121 are formed from different metal plates. For example, the peripheral conductor portion 121 may be fitted into the central conductor portion 111.
[0017] FIG. 6 shows an example of the configuration of a slot antenna 1 in an embodiment of the present invention. The slot antenna 1 in this embodiment has internal plates 141-143 between two antenna plates 100, 101 arranged parallel to each other, and which have approximately the same size as the antenna plates 100, 101, and in this embodiment are configured as internal metal plates.
[0018] FIG. 7 shows the directivity of the slot antenna 1 in one embodiment of the present invention. In this embodiment, the antenna is a waveguide slot array antenna having eight elements supported by a flange, and as shown in the figure, omni-directionality is obtained in the horizontal plane. Figures 8 to 10 show configuration examples of a 2-element, 4-element, and 8-element waveguide slot array antenna 1 in the 150 GHz band, respectively, and Figures 11 to 13 show the gain and vertical beamwidth selectivity in each configuration. Here, the 2-element case refers to the case with two slots, while the 4-element and 8-element cases refer to the case with four and eight slots, respectively. In this embodiment, in the case of two elements, the gain is about 6 dBi and the beam width is about 41 degrees, in the case of four elements, the gain is about 8 dBi and the beam width is about 23 degrees, and in the case of eight elements, the gain is about 10 dBi and the beam width is about 11 degrees. Although not shown, in the case of one element, the gain is about 2 dBi and the beam width in the vertical plane is about 70 degrees. Although the configuration is similar, any desired characteristic can be realized simply by changing the number of slot elements, and the selectivity of the beam width in the vertical plane is also high.
[0019] In one embodiment of the present invention, the metal plates may be bonded together by diffusion bonding. When two antenna plates are provided and the antenna plates are formed of metal plates, the two antenna plates may be bonded together by diffusion bonding. When an internal plate is provided and the internal plate is configured as an internal metal plate, the antenna plate and the internal plate, when there are multiple internal plates, the internal plates may be bonded together, and the internal plate and the antenna plate may be bonded together by diffusion bonding. This configuration allows for inexpensive manufacturing by diffusion bonding.
[0020] 14 and 15 show examples of the configuration of a slot antenna 1 in one embodiment of the present invention. In this embodiment, the antenna plate 100 is formed from a substrate 150 having a dielectric portion 152 and a metal portion. By cutting slots on both the front and back of the SIW to create a slot antenna 1, it is possible to combine an antenna that radiates toward the front side and an antenna that radiates toward the back side to create an omnidirectional antenna.
[0021] As shown in Fig. 15, the configuration may include two substrates 150 on the front and back, each of which includes metal portions 154 and 155 that are conductors, and dielectric portions 152 and 153. Alternatively, as shown in Fig. 16, the configuration may include metal portions 154 and 155 on the front and back of dielectric portion 152. In this way, the present invention can be applied to a waveguide, so-called SIW, formed on the dielectric substrate 150. In addition, since an omni-directional antenna can be realized without multi-layering the substrate 150, it is also excellent in terms of manufacturing costs. Thus, the present invention is applicable not only to waveguides, but also to post-wall waveguides (PPW) excited in TE mode, substrate 150 integrated waveguides (SIW), and the like.
[0022] 16 and 17 show a slot antenna 1 in one embodiment of the present invention. The slot antenna 1 in this embodiment has a cross section, as viewed from above in FIGS. 1 to 3, of a substantially rectangular parallelepiped having corner portions 161 cut out into substantially triangular shapes at the four corners. It is easier to manufacture if the cross section is a rectangular parallelepiped as shown in FIG. 18, but the antenna characteristics will be improved if it is sharply cut into a triangle as shown in FIG.
[0023] FIG. 19 shows a method for manufacturing the slot antenna 1 in one embodiment of the present invention. The method for manufacturing the slot antenna 1 in this embodiment is a method for manufacturing the slot antenna 1 having omni-directivity.
[0024] The slot antenna 1 has two antenna plates 100 arranged parallel to each other. The antenna plate 100 has an antenna portion 110 and a peripheral portion 120. The antenna portion 110 has a central conductor portion 111, which has a slot 112. The peripheral portion 120 has a peripheral conductor portion 121 formed to surround the antenna portion 110.
[0025] The method for manufacturing the slot antenna 1 in this embodiment includes an antenna plate forming step S10 in which the center conductor portion 111 and the peripheral conductor portion 121 are formed from a single metal plate 130, and a metal plate joining step S20 in which the metal plates are joined together. Due to the simple configuration as described above, the manufacturing is easy.
[0026] In one embodiment of the present invention, the metal plate joining step S20 of joining the metal plates together is a step of joining them by diffusion bonding.
[0027] In this embodiment, the diffusion bonding is performed by bonding metal plates together and applying pressure to minimize plastic deformation at a temperature below the melting point of the base material of the metal plates, thereby achieving a metallic bond between the bonding surfaces. In this embodiment, the copper plates are bonded by diffusion bonding, which makes microfabrication easy.
[0028] FIG. 20 shows a method for manufacturing the slot antenna 1 in one embodiment of the present invention. The manufacturing method of the slot antenna 1 in this embodiment further includes a cutting step S30 of cutting off the four corners of the approximately rectangular parallelepiped cross section into approximately triangular shapes. This configuration improves the characteristics of the antenna.
[0029] FIG. 21 shows a method for manufacturing the slot antenna 1 in one embodiment of the present invention. In the method for manufacturing the slot antenna 1 in this embodiment, the antenna plate forming step of forming the central conductor portion 111 and the peripheral conductor portion 121 from one metal plate 130 includes a slot forming step S15 of forming slots by etching. Specifically, after the antenna plate pre-formation step S13, a slot is formed by etching in a slot formation step S15, and the formation of the antenna plate is completed in a post-antenna plate formation step S17.
[0030] In this embodiment, a photomask is placed over a metal plate and immersed in an etching solution, thereby etching the metal plate into a desired pattern. In this embodiment, the slots are formed by etching a thin copper plate, which facilitates precise machining. Furthermore, by forming the slots by etching and then overlapping the copper sheets by diffusion bonding, the manufacturing process can be made easier and more inexpensive.
[0031] It goes without saying that the present invention is not limited to the above-mentioned embodiments, and includes various embodiments within the scope of the present invention. [Explanation of symbols]
[0032] 1 Slot Antenna 100, 101 Antenna board 110 Antenna section 111 Center conductor 112~119 Slots 120 Periphery 121 Peripheral conductor 130 A metal plate 141~143 Internal plate 150,151 Substrate 152, 153 Dielectric part 154, 155 Metal parts 161 Corner section
Claims
1. A slot antenna having omni-directional characteristics, It has two antenna plates arranged parallel to each other, the antenna plate has an antenna portion and a peripheral portion, The antenna unit includes: A central conductor portion is provided. The central conductor portion has a slot, The peripheral portion has a peripheral conductor portion formed to surround the antenna portion.
2. 2. The slot antenna according to claim 1, wherein the frequency of the radiated radio waves is equal to or higher than the millimeter wave band.
3. The slot antenna according to claim 2 , wherein the central conductor portion and the peripheral conductor portion are formed from a single metal plate.
4. an inner plate having substantially the same size as the antenna plates is disposed between the two antenna plates arranged in parallel to each other; The slot antenna of claim 3 , wherein the inner plate is formed from a metal plate.
5. 3. The slot antenna according to claim 2, wherein the two antenna plates arranged parallel to each other are formed from metal plates of substantially the same shape.
6. 3. The slot antenna according to claim 2, wherein the two antenna plates are formed as a single waveguide.
7. The slot antenna according to claim 2 , wherein the antenna plate is formed from a substrate having a dielectric portion and a metal portion.
8. 8. The slot antenna according to claim 1, wherein the widths WO of the peripheral conductor portions formed on both sides of the central conductor portion are equal to or greater than the width WC of the central conductor portion.
9. 8. The slot antenna according to claim 1, wherein the distance between the two antenna plates arranged parallel to each other is 2 mm or less.
10. 8. The slot antenna according to claim 1, wherein the cross section has a shape of a substantially rectangular parallelepiped having four corners cut into substantially triangular shapes.
11. 6. The slot antenna according to claim 3, wherein the metal plates are joined together by diffusion bonding.
12. A method for manufacturing an omnidirectional slot antenna, comprising the steps of: The slot antenna is It has two antenna plates arranged parallel to each other, the antenna plate has an antenna portion and a peripheral portion, The antenna unit includes: A central conductor portion is provided. The central conductor portion has a slot, The peripheral portion has a peripheral conductor portion formed to surround the antenna portion, an antenna plate forming step of forming the central conductor portion and the peripheral conductor portion from a single metal plate; and A method for manufacturing a slot antenna, comprising a metal plate joining step of joining the metal plates to each other.
13. The method for manufacturing a slot antenna according to claim 12, wherein the metal plate joining step of joining the metal plates to each other is a step of joining the metal plates by diffusion bonding.
14. The method for manufacturing a slot antenna according to claim 12, further comprising a cutting step of cutting off four corners of the approximately rectangular parallelepiped cross section into approximately triangular shapes.
15. 15. The method for manufacturing a slot antenna according to claim 12, wherein the antenna plate forming step of forming the central conductor portion and the peripheral conductor portion from a single metal plate includes a slot forming step of forming a slot by etching.
Citation Information
Patent Citations
Combined antenna
JP2007059959A