Integrated waveguide antennas and array antennas

Abstract

To achieve both higher antenna gain and shorter antenna spacing.SOLUTION: It has a substrate integrated waveguide section, radiating section consisting of a plurality of metal strips, and metal wall, the substrate integrated waveguide section and the radiating section are connected on a dielectric substrate, and the metal wall is placed from a first position at a first distance in the direction of the radiating section from the interface where the substrate integrated waveguide section and the radiating section are connected to a second position at a second distance longer than the first distance in the direction of the substrate integrated waveguide section.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0005]

[0001] The present invention relates to a substrate integrated waveguide antenna and an array antenna.

Background Art

[0002] In next-generation communication Beyond 5G / 6G, for example, in order to achieve a communication speed of about 100 Gbps, the use of radio waves in the sub-terahertz band is being considered. Since compound semiconductor amplifiers can operate at higher frequencies and higher outputs than silicon-based amplifiers, they are expected to be applied to Beyond 5G / 6G as sub-terahertz band semiconductor amplifiers.

[0003] On the other hand, since the sub-terahertz band has the property of radio wave rectilinearity, beam control by an array antenna in mobile communication may be required. The size of an antenna in the sub-terahertz band may be larger than that of a planar antenna such as a patch antenna used in the millimeter wave band. Therefore, it is difficult to realize an array antenna that mounts an amplifier and a planar antenna in a one-to-one correspondence. Thus, a three-dimensional stacked antenna array structure that is easy to mount an amplifier and an antenna in a one-to-one correspondence has been proposed.

[0004] Examples of sub-terahertz band amplifiers include a high electron mobility transistor (InP-based HEMT) in which an indium aluminum arsenide (InAlAs) electron supply layer / indium gallium arsenide (InGaAs) channel layer is formed on an indium phosphide (InP) substrate, a HEMT (metamorphic HEMT, mHEMT) in which an InAlAs electron supply layer / InGaAs channel layer is formed on a gallium arsenide (GaAs) substrate via a metamorphic buffer layer, and a heterojunction bipolar transistor (InP-based HBT) in which an InP emitter layer / gallium arsenide antimonide (GaAsSb) base layer / In(Al)GaAs collector layer, etc. are formed on an InP substrate. Since these compound semiconductor amplifiers can operate at higher frequencies and higher outputs than silicon-based amplifiers, they are expected to be applied to Beyond 5G / 6G.

[0005] The following patent documents describe the technology related to antennas. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] WO2016 / 111107 [Patent Document 2] Japanese Patent Publication No. 2011-109438 [Patent Document 3] WO2019 / 008852 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, there are no antennas that are adequately capable of handling next-generation communications.

[0008] For example, an antenna with a horn section has high individual antenna gain, but because the antenna spacing is larger than the wavelength of a given frequency, beam control (angle, grating lobe) can be difficult.

[0009] On the other hand, antennas without a horn section allow for antenna spacing smaller than the wavelength of a given frequency, making beam control easier, but resulting in lower gain for individual antennas.

[0010] Thus, improving antenna gain and shortening the antenna spacing can sometimes be contradictory, making it difficult to achieve both simultaneously.

[0011] Therefore, one disclosure provides a substrate-integrated waveguide antenna and an array antenna that achieve both improved antenna gain and reduced antenna spacing. [Means for solving the problem]

[0012] The waveguide comprises a substrate-integrated waveguide section, a radiating section composed of multiple metal strips, and a metal wall. The substrate-integrated waveguide section and the radiating section are connected on a dielectric substrate, and the metal wall is positioned at a second position, which is a distance greater than the first distance, from a first position at a first distance in the direction of the radiating section from the interface where the substrate-integrated waveguide section and the radiating section are connected. [Effects of the Invention]

[0013] One disclosure makes it possible to achieve both improved antenna gain and reduced antenna spacing. [Brief explanation of the drawing]

[0014] [Figure 1A] Figure 1A shows an example configuration of antenna 100. [Figure 1B] Figure 1B shows an example configuration of antenna 100. [Figure 1C] Figure 1C shows an example configuration of antenna 100. [Figure 2A] Figure 2A shows an example of the simulation results for antenna 100. [Figure 2B] Figure 2B shows an example of the simulation results for antenna 100. [Figure 2C] Figure 2C shows an example of the simulation results for antenna 100. [Figure 3A] Figure 3A shows an example of a manufacturing method for antenna 100. [Figure 3B] Figure 3B shows an example of a manufacturing method for antenna 100. [Figure 3C] Figure 3C shows an example of a manufacturing method for antenna 100. [Figure 3D] Figure 3D shows an example of a manufacturing method for antenna 100. [Figure 3E] Figure 3E shows an example of a manufacturing method for antenna 100. [Figure 3F] Figure 3F shows an example of a manufacturing method for antenna 100. [Figure 3G] FIG. 3G is a diagram showing an example of a manufacturing method of the antenna 100. [Figure 3H] FIG. 3H is a diagram showing an example of a manufacturing method of the antenna 100. [Figure 3I] FIG. 3I is a diagram showing an example of a manufacturing method of the antenna 100. [Figure 3J] FIG. 3J is a diagram showing an example of a manufacturing method of the antenna 100. <000009​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Figure 8B shows an example of simulation results for antenna array 300. [Figure 8C] Figure 8C shows an example of simulation results for antenna array 300. [Figure 8D] Figure 8D shows an example of simulation results for antenna array 300. [Figure 9A] Figure 9A shows an example of a manufacturing method for the antenna array 300. [Figure 9B] Figure 9B shows an example of a manufacturing method for the antenna array 300. [Figure 9C] Figure 9C shows an example of a manufacturing method for the antenna array 300. [Figure 9D] Figure 9D shows an example of a manufacturing method for the antenna array 300. [Figure 9E] Figure 9E shows an example of a method for manufacturing the antenna array 300. [Figure 10A] Figure 10A shows an example of the configuration of antenna array 400. [Figure 10B] Figure 10B shows an example of the configuration of the antenna array 400. [Figure 11A] Figure 11A shows an example of the simulation results for antenna array 400. [Figure 11B] Figure 11B shows an example of the simulation results for antenna array 400. [Figure 11C] Figure 11C shows an example of the simulation results for antenna array 400. [Figure 12A] Figure 12A shows an example of a manufacturing method for the antenna array 400. [Figure 12B] Figure 12B shows an example of a manufacturing method for the antenna array 400. [Figure 12C] Figure 12C shows an example of a manufacturing method for the antenna array 400. [Figure 13A] Figure 13A shows an example of the configuration of antenna array 500. [Figure 13B]Figure 13B shows an example of the configuration of antenna array 500. [Figure 14A] Figure 14A shows an example of a simulation of antenna array 500. [Figure 14B] Figure 14B shows an example of a simulation of antenna array 500. [Figure 14C] Figure 14C shows an example of a simulation of antenna array 500. [Figure 15A] Figure 15A shows an example of a manufacturing method for the antenna array 500. [Figure 15B] Figure 15B shows an example of a manufacturing method for the antenna array 500. [Figure 15C] Figure 15C shows an example of a manufacturing method for the antenna array 500. [Figure 15D] Figure 15D shows an example of a manufacturing method for the antenna array 500. [Figure 15E] Figure 15E shows an example of a manufacturing method for the antenna array 500. [Figure 15F] Figure 15F shows an example of a manufacturing method for the antenna array 500. [Figure 15G] Figure 15G shows an example of a manufacturing method for the antenna array 500. [Figure 15H] Figure 15H shows an example of a manufacturing method for the antenna array 500. [Figure 16A] Figure 16A shows an example of the configuration of the antenna array 600. [Figure 16B] Figure 16B shows an example of the configuration of the antenna array 600. [Figure 17A] Figure 17A shows an example of the configuration of the antenna module 700. [Figure 17B] Figure 17B shows an example of the configuration of the antenna module 700. [Figure 18A] Figure 18A shows an example of the configuration of the antenna module 800. [Figure 18B]Figure 18B shows an example of the configuration of the antenna module 800. [Figure 19] Figure 19 shows an example of the configuration of the antenna module 900. [Figure 20A] Figure 20A shows an example of the configuration of antenna module 1000. [Figure 20B] Figure 20B shows an example of the configuration of antenna module 1000. [Figure 21] Figure 21 shows an example of a table relating to the dielectric constant, dielectric loss, and thermal conductivity of a material. [Modes for carrying out the invention]

[0015] [First Embodiment] A first embodiment will be described.

[0016] <Example of antenna configuration in the first embodiment> Figure 1 shows an example of the antenna 100 configuration. Figure 1A shows an example of a top view of the antenna 100, Figure 1B shows an example of a cross-sectional view of the antenna 100, and Figure 1C shows an example of a front view of the antenna 100.

[0017] Antenna 100 is an SIW antenna, for example, composed of an SIW section and multiple metal strip radiating sections. Antenna 100 has a metal wall (reflector) surrounding the SIW section positioned at a first distance (r1) in the main lobe direction from the interface between the SIW section and the radiating section at a predetermined frequency, and at a second distance (r2) from there in the back lobe direction which is longer than r1. The metal wall is a plate-shaped metal having a predetermined width, and is positioned, for example, parallel (approximately parallel) to the interface. r1 is half a wavelength (λ / 2) in the dielectric substrate at the predetermined frequency, and r2 is in the range of λ / 2-λ / 10 to λ / 2+λ / 5 of air (wavelength in air at a certain frequency). The metal wall (reflector) has an outer circumference with a first width (A1) from the front and back surfaces of the SIW section and a second width (A2) from the side surface of the SIW section, and the first width (A1) is at least greater than λ / 10 of air. Furthermore, the width (w) of the SIW section shall be within the range that results in TE10 mode (single mode) at a predetermined frequency. Also, the length (L) of the metal strip in the radiating section shall be within half of the w ± substrate through-via diameter (D). In addition, the ratio of the width (W) and spacing (S) of each metal strip in the radiating section shall be gradually decreased in the direction of the main lobe. For example, it is preferable that the sum of S and W of each metal strip at a predetermined frequency be λ / 4 of the dielectric substrate, and that the S:W ratio be gradually changed from 1:9 to 9:1 in the direction of the main lobe.

[0018] <Effects of the antenna in the first embodiment> The effect of antenna 100 in the first embodiment will be described. Figure 2 shows an example of simulation results for antenna 100.

[0019] Figure 2A shows an example of simulation results of the dependence of the antenna gain on the second distance (r2) for an SIW antenna structure having a metal wall with the same outer circumference, where the first width (A1) and second width (A2) are the same. A1 and A2 are 0.1 mm, 0.3 mm, 0.5 mm, and 0.75 mm. The horizontal axis of the graph is the second distance (r2), and the vertical axis is the antenna gain. The dielectric substrate is a SiC substrate with a substrate thickness of 100 μm. The SIW section width (w) is 0.48 mm, which is within the range of TE10 mode. The diameter of the through-substrate via wiring is 80 μm. The length (L) of the metal strip is the same as the SIW section width, 0.48 mm. The sum of the spacing (S) and width (W) of each metal strip is one-quarter wavelength (λ / 4) of the dielectric substrate at a predetermined frequency, and the S:W ratio is gradually changed from 1:9 to 9:1 in the main lobe direction. In a SiC substrate with a dielectric constant of 9.74 (see Table 1 in Figure 21), λ / 4 is 80 μm at 300 GHz. The first distance (r1) is the distance from the interface between the SIW and the radiating portion to the point where the highest electric field strength is observed in the radiating portion (in the simulation), and at 300 GHz, it is 160 μm, which corresponds to λ / 2 in the SiC substrate. The distance from the point where the highest electric field strength is observed in the radiating portion to the metal wall is the second distance (r2).

[0020] The antenna gain of an SIW antenna structure with a metal wall (reflector) of A1, A2 = 0.75 mm increases compared to the antenna gain of the reference structure (6.9 dBi) when the second distance (r2) is in the range of 0.4 mm to 0.7 mm. This range of r2 = 0.4 mm to 0.7 mm corresponds to the range of λ / 2 - λ / 10 to λ / 2 + λ / 5 for air. Furthermore, while the antenna gain decreases as the outer width of the metal wall (A1, A2) decreases, it is possible to improve the antenna gain compared to the reference structure even when A1, A2 = 0.1 mm or more. This range of A1, A2 = 0.1 mm corresponds to λ / 10 for air.

[0021] Furthermore, expressions such as "corresponding to ~(wavelength) in air" are, for example, 「 This can also be rephrased as "corresponding to a wavelength of a given frequency in air."

[0022] Figure 2B shows an example of simulation results for the dependence of the antenna gain on the second distance (r2) of an SIW antenna structure having outer metal walls of different widths (A1) and (A2). When A1 = 0.5 mm, A2 = 0 mm, 0.1 mm, 0.5 mm; when A1 = 0.1 mm, A2 = 0.1 mm, 0.5 mm. Other conditions are the same as in Figure 2A.

[0023] When A1 = 0.5 mm, the antenna gain increases beyond the antenna gain of the reference structure (6.9 dBi) when the second distance (r2) is in the range of 0.4 mm to 0.7 mm. This range of r2 = 0.4 mm to 0.7 mm corresponds to the range of air (λ / 2 - λ / 10 to λ / 2 + λ / 5). Furthermore, the antenna gain decreases slightly as A2 decreases, but even at A2 = 0 mm, the maximum antenna gain is 9.4 dBi, which is a high value. On the other hand, when A1 = 0.1 mm, the antenna gain increases beyond the antenna gain of the reference structure (6.9 dBi) when the second distance (r2) is in the range of 0.4 mm to 0.7 mm, but even when A2 is extended to 0.5 mm, the maximum antenna gain is 8 dBi, which is the same as when A2 = 0.1 mm.

[0024] Figure 2C shows an example of simulation results for the dependence of the antenna gain on the second distance (r2) of an SIW antenna structure with a metal wall at various frequencies. When the outer width of the metal wall (A1, A2) is 0.75 mm, the antenna gain improves even in the frequency band of 280 GHz to 320 GHz (bandwidth of 40 GHz) when the second distance (r2) is in the range of 0.5 mm to 0.65 mm, enabling a bandwidth of more than 10% above the center frequency (300 GHz). This r2 = 0.5 mm to 0.65 mm corresponds to the range of λ / 2 to λ / 2 + 3λ / 20 for air.

[0025] At a given frequency, if the metal wall (reflector) surrounding the SIW is positioned at a location λ / 2 of the dielectric substrate in the main lobe direction from the interface between the SIW and the radiating section, and λ / 4 of the air in the back lobe direction, the reflected wave will be in opposite phase to the forward wave, thus reducing the antenna gain. On the other hand, if the metal wall (reflector) surrounding the SIW is positioned λ / 2 of the air in the back lobe direction, the reflected wave will be in phase with the forward wave, thus improving the antenna gain. This is thought to be the cause of the above phenomenon.

[0026] Furthermore, in the range r2 = λ / 2 - λ / 10 to λ / 2 + λ / 5, the phase shift is smaller than λ / 4, so the improvement in antenna gain is maintained. Also, as the width of the outer circumference of the metal wall narrows, the reflection area decreases, and the electric field wraps around to the top and bottom surfaces of the metal wall, so the peak value of the antenna gain decreases and the peak r2 is extended. Similarly, because the electric field wraps around to the top and bottom sides of the metal wall, the antenna gain strongly depends on the first width (A1), but does not wrap around to the left and right sides of the metal wall as much, so the second width (A2) is not very dominant. For this reason, A2 is not necessary, but it is desirable to electrically connect it in order to make the potential of the metal wall (reflector) the same. In addition, when the center frequency is 300 GHz and the bandwidth is 40 GHz (280 GHz to 320 GHz), the width of λ / 2 of the air is about ±λ / 30, which is well within the range of the phase shift mentioned above, so broadband operation becomes possible.

[0027] As described above, the SIW antenna structure in the first embodiment makes it possible to improve antenna gain without providing an SIW horn section. Therefore, it becomes possible to shorten the antenna spacing even when an array is formed.

[0028] <Antenna manufacturing method in the first embodiment> An example of a method for manufacturing an antenna in the first embodiment will be described. Figure 3 is a diagram showing an example of a method for manufacturing an antenna 100. Figure 3 shows, for example, the method for manufacturing an antenna 100, step by step. Figure 3 also shows, for example, intermediate and completed products (such as an antenna 100 in the process of being manufactured) in the method for manufacturing an antenna 100.

[0029] Figure 3A: Surface process A wafer is fabricated using a SiC substrate as the dielectric substrate, with a surface metal and a surface metal strip formed on the surface of the SiC substrate. The surface metal and surface metal strip are composed of, for example, a nickel (Ni) / gold (Au) structure and are fabricated using methods such as patterning, vacuum deposition, sputtering, and plating. The Ni layer is at least 0.1 μm thick to serve as a via etching stopper.

[0030] Figure 3B: Substrate thinning After applying adhesive to the wafer surface and attaching it to a support substrate, grinding and polishing are performed from the back side of the SiC substrate to thin the SiC substrate thickness to 100 μm.

[0031] Figure 3C: Metal mask formation A metal mask is formed on the back surface of the SiC substrate. The metal mask is composed of, for example, a titanium (Ti) / copper (Cu) / Ni structure and is fabricated using techniques such as patterning, vacuum deposition, sputtering, or plating. The Ni film thickness is determined by the selectivity ratio of the dry etching used for subsequent via hole formation. For example, if the selectivity ratio is 100, the Ni film thickness must be at least 1 μm. The Ni film thickness is set to, for example, 2 μm. The diameter of the metal mask opening for forming the via holes is set to 80 μm.

[0032] Figure 3D: Via etching Dry etching of a SiC substrate is performed using a mixed gas of sulfur hexafluoride (SF6) and oxygen (O2) to form via holes that penetrate the substrate. The dry etching rate is 1.6 μm / min for 68 minutes. This results in an etching depth of approximately 109 μm of SiC, and the surface metal Ni layer functions sufficiently as an etching stopper.

[0033] Figure 3E: Metal mask removal Remove the remaining metal mask after dry etching. Here, the surface metal is protected by patterning, and the metal mask is etched using an etchant such as an acid.

[0034] Figure 3F: Seed metal deposition Seed metal is deposited inside via holes and on the back surface of the SiC substrate. Here, the seed metal consists of a Ti / Au layer and is formed using sputtering. To prevent the seed metal inside the via holes from breaking, an Au layer with a thickness of at least 1 μm is deposited on the back surface of the SiC substrate.

[0035] Figure 3G: Patterning Patterning is performed to create openings in the areas where the back metal and back metal strip will be formed. The resist thickness should be 11 μm or more.

[0036] Figure 3H: Plating A 10 μm thick Au plating layer is formed.

[0037] Figure 3I: Seed metal removal After removing the resist, the seed metal is removed. Here, the metal inside the via holes is protected by patterning, and the Ti / Au layer is etched using an etchant such as an acid. This forms the back metal, back metal strip, and through-via wiring on the substrate. Then, after peeling the wafer from the support substrate, the adhesive is removed with an organic solvent.

[0038] Figure 3J: Chipification The back surface of the wafer is attached to dicing tape, and then chipped using ultrasonic blade dicing.

[0039] Figure 3K: Mounted on a metal wall. The SIW antenna structure is completed by mounting the chipped SIW antenna at a predetermined position on a metal wall (reflector) having an aperture of the same size as the SIW antenna. For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm.

[0040] Figure 3L is a front view of the completed SIW antenna structure (antenna 100) in the above manufacturing method. The outer widths (A1, A2) of the metal walls shall be at least 0.1 mm.

[0041] <Modified form of the first embodiment> A modified example of the first embodiment will now be described.

[0042] <Example of antenna configuration in a modified version of the first embodiment> Figure 4 shows an example of the antenna 200 configuration. Figure 4A shows an example of a top view of the antenna 200, and Figure 4B shows an example of the antenna 200. This figure shows an example of a front view.

[0043] As shown in Figure 4, the SIW antenna (antenna 200) in a modified example of the first embodiment has an opening between the SIW section and the metal wall (reflector).

[0044] <Effect of the antenna in a modified example of the first embodiment> The antenna 200 in the modified version of the first embodiment has the same effect as the antenna 100 in the first embodiment. As shown in Figures 4A and 4B, the antenna 200 has a configuration in which the metal wall (reflector) and the metal back surface of the SIW part are in contact in the top view and front view, respectively, and the top and side surfaces of the SIW part are separated from the metal wall by an opening width (Open).

[0045] Figure 5 shows an example of simulation results of the dependence of antenna gain on the second distance (r2) for an SIW antenna structure (antenna 200) having metal walls (reflectors) with different aperture widths (Open). The horizontal axis represents the second distance (r2), and the vertical axis represents the antenna gain. The outer widths (A1, A2) of the metal walls (reflectors) are set to 0.3 mm. The antenna gain decreases slightly as the aperture width (Open) increases, but, similar to the first embodiment, it increases above the antenna gain of the reference structure (6.9 dBi) when the second distance (r2) is in the range of 0.45 mm to 0.75 mm. As the aperture width (Open) increases, the reflection area decreases, so the peak value of the antenna gain decreases. On the other hand, compared to the case where A2 = 0.75 mm, the electric field wraps around to the upper and lower surfaces of the metal walls (reflectors), so although r2 is extended slightly (0.05 mm), the position of the upper and lower surfaces of the metal walls (reflectors) does not change, so the peak r2 does not change.

[0046] As described above, in the modified SIW antenna structure (antenna 200) of the first embodiment, it is possible to improve the antenna gain even if there is a gap (opening) between the metal wall and the SIW antenna.

[0047] <Manufacturing method for an antenna in a modified example of the first embodiment> An example of a method for manufacturing the antenna 200 in a modified version of the first embodiment will be described. Figure 6 is a diagram showing an example of a method for manufacturing the antenna 200. Figure 6 shows, for example, the method for manufacturing the antenna 200, step by step. Figure 6 also shows, for example, the intermediate and completed products (antenna 200 in the process of being manufactured) in the method for manufacturing the antenna 200.

[0048] Figure 6A: Bonding of the lower metal plate The SIW antenna chip, created using the process shown in Figure 3J, is bonded to the lower metal plate at a predetermined position using conductive adhesive. For example, at 300 GHz, r1 is 0.16 mm, and while antenna gain improves in the range of r2 from 0.4 to 0.7 mm, a range of 0.5 to 0.65 mm is preferable.

[0049] Figure 6B is a front view of the antenna being constructed as shown in Figure 6A.

[0050] Figure 6C: Upper metal plate attached A concave upper metal plate having a groove larger than the SIW antenna size is attached to the lower metal plate. This completes the SIW antenna structure with an opening, as shown in the modified version of the first embodiment.

[0051] Figure 6D is a front view of the antenna. The antenna consists of a metal wall (reflector) made up of an upper metal plate, a conductive adhesive layer, and a lower metal plate. The outer width of the metal wall (A1, A2) is 0.3 mm, and the width of the opening (Open) is 0.02 mm.

[0052] Figure 6E: Bonding of the upper metal plate Alternatively, the opening may be filled with a conductive adhesive. In this case, the process shown in Figure 6E is performed.

[0053] Figure 6F is a front view of the antenna with the opening filled with conductive adhesive. The antenna is composed of a metal wall (reflector) consisting of an upper metal plate, a conductive adhesive layer, and a lower metal plate, as described above.

[0054] In the above example, a flat lower metal plate was used, but grooves may also be provided in the upper and lower metal plates, or a configuration with a lower metal plate having a groove larger than the SIW antenna size and a flat upper metal plate may also be used.

[0055] Furthermore, although SiC was used as the dielectric substrate in the above example, dielectric substrates such as InP, GaAs, high-resistivity Si, alumina, GaN, AlN, diamond, LTCC, quartz, polyimide, Teflon®, and other high-dielectric ceramics may also be used.

[0056] [Second Embodiment] A second embodiment will now be described.

[0057] <Example of antenna array configuration in the second embodiment> Figure 7 shows an example of the configuration of the antenna array 300. The antenna array 300 (SIW antenna array) is an array of SIW antennas, each consisting of an SIW section and multiple metal strip radiating sections, arranged in parallel. At a predetermined frequency, a metal wall (reflector) is placed around the entire SIW section of the SIW antenna array at a position a first distance (r1) in the main lobe direction from the interface between the SIW section and the radiating section, and a second distance (r2) longer than r1 in the back lobe direction from that position. At this time, at the predetermined frequency, r1 is half a wavelength (λ / 2) within the dielectric substrate, and r2 is in the range of λ / 2-λ / 10 to λ / 2+λ / 5 of air. The metal wall (reflector) has an outer circumference with a first width (A1) from the front and back surfaces of the SIW section and a second width (A2) from the side surface of the SIW section, and the first width (A1) is at least greater than λ / 10 of air. Note that the antenna array is sometimes called an array antenna.

[0058] <Effects of the antenna array in the second embodiment> The effects of the SIW antenna array in the second embodiment will be described. Figure 8 shows an example of the simulation results for the antenna array 300.

[0059] As shown in Figures 7A and 7B, the antenna array 300 has a configuration in which a metal wall (reflector) is placed on an integrated SIW antenna array, which is an array of SIW antenna structures (for example, the antenna in the first embodiment) arranged in parallel side by side.

[0060] The dielectric substrate shall be a SiC substrate. The SiC substrate thickness shall be 100 μm. The SIW section width (w) shall be 0.48 mm within the range that results in TE10 mode. The diameter of the through-substrate via wiring shall be 80 μm. The length (L) of the metal strip shall be the same as the SIW section width, 0.48 mm. The sum of the spacing (S) and width (W) of each metal strip shall be one-quarter wavelength (λ / 4) of the dielectric substrate at a predetermined frequency, and the S:W ratio shall be gradually changed from 1:9 to 9:1 in the main lobe direction. λ / 4 in a SiC substrate with a dielectric constant of 9.74 is 80 μm at 300 GHz. The antenna spacing (a) shall be 0.65 mm. The outer widths (A1, A2) of the metal walls shall be 0.75 mm.

[0061] Figure 8A shows an example of simulation results for the dependence of the antenna gain on the second distance (r2) of SIW antenna structure 2 with a metal wall (reflector). The horizontal axis represents the second distance (r2), and the vertical axis represents the antenna gain. The antenna gain increases from 12.1 dBi of the reference SIW antenna array structure when the second distance (r2) is in the range of 0.4 mm to 0.7 mm. This r2 corresponds to the range of λ / 2 - λ / 10 to λ / 2 + λ / 5 for air.

[0062] Figure 8B shows an example of the radiation pattern when the phase shift between antennas is 0 degrees at 300 GHz. r² is 0.58 mm. Figures 8C and 8D show examples of the angular dependence of gain when the phase shift between antennas is 0 degrees and -120 degrees, respectively. The dashed and solid lines in the graphs represent Theta (up / down) and Phi (horizontal), respectively, as shown in Figure 8B. By modulating the phase of each antenna by -120 degrees, it is possible to swing the beam horizontally by 24 degrees. In this case, the gain difference between the main lobe and the side lobes is approximately 8 dB.

[0063] In the SIW antenna array structure of the second embodiment, antennas can be arranged in parallel horizontally at intervals narrower than one wavelength of air, making it possible to swing the beam horizontally.

[0064] <Method for manufacturing an antenna array in the second embodiment> Figure 9 shows an example of a manufacturing method for the antenna array 300. The process up to chip formation is the same as in the first embodiment. The antenna array 300 has, for example, an SIW section width (w) of 0.48 mm and an antenna spacing (a) of 0.65 mm.

[0065] Figure 9A: Chip design A wafer with multiple SIW antenna arrays formed on it is chipped using ultrasonic blade dicing.

[0066] Figure 9B: Lower metal bonding The SIW antenna array chip is bonded to the lower metal plate in a predetermined position using conductive adhesive. For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Figure 9C is a front view of the antenna array.

[0067] Figure 9D: Upper metal bonding The SIW antenna array structure is completed by attaching a concave upper metal plate, which has a groove larger than the SIW antenna array size, to the lower metal plate and filling the gap with conductive adhesive. Figure 9E is a front view of the antenna array. The antenna array consists of a metal wall (reflector) made up of an upper metal plate, a conductive adhesive layer, and a lower metal plate. The outer width of the metal wall (A1, A2) is 0.75 mm, and the width of the opening (Open) is 0.02 mm. The opening does not necessarily need to be filled with conductive adhesive.

[0068] <Modified form of the second embodiment> A modified example of the second embodiment will now be described.

[0069] <Example of antenna array configuration in a modified version of the second embodiment> Figure 10 shows an example of the configuration of the antenna array 400. The antenna array 400 shares through-vias of the substrate in the SIW portions of adjacent SIW antennas. In addition, the metal strips of each radiating portion may be connected.

[0070] <Effects of the antenna array in a modified example of the second embodiment> In the modified version of the second embodiment, the antenna array 400 is configured to share through-substrate via wiring of the SIW antenna structure, thereby shortening the antenna spacing (a). Figures 10A and 10B show the top view and front view, respectively. The dielectric substrate is a SiC substrate. The SiC substrate thickness is 100 μm. The SIW section width (w) is 0.48 mm within the range of TE10 mode. The diameter of the through-substrate via wiring is 80 μm. The length (L) of the metal strip is 0.46 mm. The sum of the spacing (S) and width (W) of each metal strip is one-quarter wavelength (λ / 4) of the dielectric substrate at a predetermined frequency, and the S:W ratio is gradually changed from 1:9 to 9:1 in the main lobe direction. λ / 4 in a SiC substrate with a dielectric constant of 9.74 is 80 μm at 300 GHz. The antenna spacing (a) is 0.48 mm, which is smaller than the air width λ / 2 (0.5 mm). The outer width of the metal wall (A1, A2) is 0.75 mm.

[0071] Figure 11 shows an example of the simulation results for antenna array 400. Figure 11A shows an example of the radiation pattern when the phase shift between antennas is 0 degrees at 300 GHz. r2 is 0.58 mm. Figures 11B and 11C show examples of the angular dependence of the gain when the phase shift between antennas is 0 degrees and -120 degrees, respectively. By modulating the phase of each antenna by -120 degrees, it is possible to swing the beam horizontally by 30 degrees, and by shortening the antenna spacing, the beam swing angle can be increased. In this case, the difference in gain between the main lobe and the side lobes is approximately 6 dB. In the above, the metal strips between each antenna are not electrically connected, but they may be electrically connected.

[0072] <Manufacturing method for an antenna array in a modified example of the second embodiment> Figure 12 shows an example of a method for manufacturing the antenna array 400. In a modified version of the second embodiment, the antenna array shares through-vias between each SIW antenna, thereby reducing the antenna spacing. In this case, the SIW width (w) is 0.48 mm, and the antenna spacing (a) is also 0.48 mm. The length (L) of the metal strip is 0.46 mm. The metal strips of each antenna may be electrically connected.

[0073] Figure 12A: Chip design A wafer with multiple SIW antenna arrays formed on it is chipped using ultrasonic blade dicing.

[0074] Figure 12B: Lower metal board Adhesion The SIW antenna array chip is bonded to the lower metal plate in a predetermined position using conductive adhesive. For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm.

[0075] Figure 12C: Bonding of the upper metal plate The SIW antenna array structure is completed by attaching a concave upper metal plate, which has a groove larger than the SIW antenna array size, to a lower metal plate and filling the gap with conductive adhesive. The antenna array consists of a metal wall (reflector) made up of an upper metal plate, a conductive adhesive layer, and a lower metal plate. The outer width of the metal wall (A1, A2) is 0.75 mm, and the width of the opening (Open) is 0.02 mm. This opening does not necessarily need to be filled with conductive adhesive.

[0076] In the modified version of the second embodiment, the SIW antenna array structure of the antenna array can be made shorter than the λ / 2 of air, which makes it possible to increase the horizontal beam swing angle.

[0077] [Third Embodiment] A third embodiment will now be described.

[0078] <Example of antenna array configuration in the third embodiment> In the second embodiment, the SIW antennas are arranged in a horizontal array. In the third embodiment, the SIW antenna array structure is formed by stacking the SIW antennas vertically. In order to suppress unnecessary grating lobes, the antenna spacing must be less than one wavelength (λ) of air, even in the vertical direction, and preferably λ / 2. In the third embodiment, the thickness in the vertical direction is controlled.

[0079] Figure 13 shows an example of the configuration of the antenna array 500. The antenna array 500 in the third embodiment is an SIW antenna array in which SIW antennas, each consisting of an SIW section and multiple metal strip radiating sections, are arranged in a vertical parallel array. At a predetermined frequency, a metal wall (reflector) surrounding the SIW section of each SIW antenna is placed at a position a first distance (r1) in the main lobe direction from the interface between the SIW section and the radiating section, and at a second distance (r2) from there in the back lobe direction which is longer than r1.

[0080] At this time, at a predetermined frequency, r1 is half a wavelength (λ / 2) within the dielectric substrate, and r2 is in the range of λ / 2-λ / 10 to λ / 2+λ / 5 of air. The metal wall (reflector) has a first width (A1) from the front and back surfaces of the SIW portion, a second width (A2) from the side surface of the SIW portion, and a third width (A3) between adjacent SIW portions. The first width (A1) is at least greater than λ / 10 of air, and the third width (A3) is at least in the range from λ / 10 of air to the difference between λ of air and the thickness of the SIW portion.

[0081] <Effects of the antenna array in the third embodiment> Figures 13A and 13B are cross-sectional and front views, respectively, showing a configuration in which a metal wall (reflector) is placed on an SIW antenna array, which is an array of SIW antenna structures arranged in parallel in a vertical line. The outer widths (A1, A2) of the metal wall (reflector) are 0.75 mm. The antenna spacing (b) is 0.4 mm, and the third width (A3) of the metal wall (reflector) is 0.28 mm. r2 is 0.58 mm.

[0082] Figure 14 shows an example of a simulation of antenna array 500. Figure 14A shows an example of the radiation pattern when the phase shift between antennas is 0 degrees at 300 GHz. Figures 14B and 14C show examples of the angular dependence of the gain when the phase shift between antennas is 0 degrees and -90 degrees, respectively. The dashed and solid lines in the graphs represent Theta (up and down) and Phi (horizontal), respectively, as shown in Figure 14A. By modulating the phase between each antenna by -90 degrees, it is possible to swing the beam 30 degrees in the vertical direction. At this time, the difference in gain between the main lobe and the side lobes is approximately 8 dB. The SIW structure allows for thinner antennas and shorter distances between antennas, making it possible to swing the beam significantly even with small phase shifts.

[0083] <Method for manufacturing an antenna array in the third embodiment> Figure 15 shows an example of a manufacturing method for the antenna array 500. Figures 15A and 15B show examples of a cross-sectional view and a front view of the SIW antenna used.

[0084] Figure 15C: Adhesion The SIW antenna chip is then reattached to the upper metal plate of the SIW antenna using conductive adhesive in the designated position. Figure 15D is a front view of the process shown in Figure 15C. For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Also, to make the antenna spacing (b) 0.4 mm, the thickness of the upper metal plate (t1) is 0.4 mm and the groove depth (d1) is 0.15 mm. The outer width (A1, A2) of the metal wall (reflector) is 0.75 mm. The third width (A3) of the metal wall (reflector) is 0.25 mm + the thickness of the conductive adhesive layer (approximately 35 μm).

[0085] Figure 15E: Upper metal plate attached Again, a concave upper metal plate with a groove larger than the SIW antenna array size is attached to the concave upper metal plate at the bottom, and the gap is filled with conductive adhesive. Figure 15F is a front view of the process shown in Figure 15E.

[0086] Figure 15G: Repeat By repeating the above process, an SIW antenna array structure is completed with four vertically stacked antennas (b) with an antenna spacing of 0.4 mm. Figure 15H is a front view of the completed antenna. The antenna consists of a metal wall (reflector) made of an upper metal plate, a conductive adhesive layer, and a lower metal plate. Also, the openings do not need to be filled with conductive adhesive.

[0087] In the SIW antenna array structure of the third embodiment, antennas can be arranged in parallel vertically at intervals narrower than one wavelength of air, making it possible to swing the beam vertically.

[0088] <Modified example of the third embodiment> Figure 16 shows an example of the configuration of the antenna array 600. In the modification of the third embodiment, the antenna array 600 is an SIW antenna array structure in which SIW antenna arrays with an antenna spacing of (a) 0.65 mm of the second embodiment are stacked vertically with an antenna spacing of (b) 0.4 mm. Figures 16A and 16B show examples of an overhead view and a front view of the SIW antenna array structure.

[0089] For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Also, to set the antenna spacing (b) to 0.4 mm, the thickness of the upper metal plate (t1) is 0.4 mm and the groove depth (d1) is 0.15 mm. The outer width (A1, A2) of the metal wall (reflector) is 0.75 mm. The third width (A3) of the metal wall (reflector) is 0.25 mm + the thickness of the conductive adhesive layer (approximately 20 μm). The antenna is composed of a metal wall (reflector) consisting of an upper metal plate, a conductive adhesive layer, and a lower metal plate. The opening may also be filled with conductive adhesive. In this case, the maximum antenna gain is 17.8 dBi at 300 GHz.

[0090] In the modified SIW antenna array structure, antennas can be arranged vertically and horizontally in parallel at intervals narrower than one wavelength of air, making it possible to swing the beam vertically and horizontally. Furthermore, in the modified SIW antenna array of the second embodiment with an antenna spacing of (a) 0.48 mm, it becomes possible to swing the beam over an even wider angle.

[0091] Although the explanation used an example where SIW antennas and antenna arrays were stacked in four vertical rows, any number of SIW antennas and antenna arrays can be stacked.

[0092] Furthermore, although the above explanation used SiC as the dielectric substrate, dielectric substrates such as InP, GaAs, high-resistivity Si, alumina, GaN, AlN, diamond, LTCC, quartz, polyimide, Teflon, and other high-dielectric ceramics may also be used.

[0093] [Fourth Embodiment] A fourth embodiment will now be described.

[0094] <Example of antenna module configuration in the fourth embodiment> Figure 17 shows an example of the configuration of the antenna module 700. The antenna module 700 in the fourth embodiment shows an example of an amplifier-integrated antenna module in which high-frequency semiconductor circuit chips such as an amplifier, mixer, and phase shifter, as well as an SIW antenna and an antenna array, are mounted on a metal housing.

[0095] First, Figures 17A and 17B show an overhead and top view, respectively, of an amplifier-integrated antenna module in which high-frequency semiconductor circuit chips such as a power amplifier, mixer, and phase shifter, and an SIW antenna are mounted on a metal housing. The SIW antenna chip is bonded to the lower metal base of the metal housing in a predetermined position using conductive adhesive (not shown). For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Next, the subterahertz band power amplifier, mixer, and phase shifter chips are sequentially bonded to the lower metal base of the metal housing. After that, the SIW antenna, power amplifier, mixer, and phase shifter are connected. Then, a concave upper metal cover with a groove larger than the size of the SIW antenna, power amplifier, mixer, and phase shifter is placed over it to complete the amplifier-integrated antenna module of Example 4. The sides of this metal housing function as metal walls (reflectors).

[0096] <Example of antenna module configuration in modified example 1 of the fourth embodiment> Figure 18 shows an example of the configuration of the antenna module 800. In the modification 1 of the fourth embodiment, Figures 18A and 18B show an overhead view and a top view of the antenna module 800. An SIW antenna array chip with an antenna spacing (a) of 0.65 mm is bonded to the lower metal base of the metal housing at a predetermined position using a conductive adhesive (not shown). For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Furthermore, a subterahertz band power amplifier, mixer, and phase shifter chip are sequentially bonded to the lower metal base of the metal housing. Then, the SIW antenna array, power amplifier, mixer, and phase shifter are connected. After that, a concave upper metal cover having a groove larger than the size of the SIW antenna array, power amplifier, mixer, and phase shifter is placed over it. At this point, to achieve an antenna spacing (b) of 0.4 mm, the thickness of the upper metal cover is set to 0.4 mm and the depth of the groove to 0.15 mm. Alternatively, the gap between the SIW section and the metal housing may be filled with conductive adhesive. By repeating this procedure, an amplifier-integrated antenna module with four vertically stacked antennas at an antenna spacing (b) of 0.4 mm is completed. The sides of this metal housing function as metal walls (reflectors).

[0097] Although the example described uses a flat lower metal base, grooves may be provided in the upper metal lid and the lower metal base, or grooves may be provided in the lower metal base to form a flat upper metal plate.

[0098] <Example of antenna module configuration in modified example 2 of the fourth embodiment> Figure 19 shows an example of the configuration of the antenna module 900. In the modified example 2 of the fourth embodiment, the antenna module 900 has an SIW antenna array chip with an antenna spacing (a) of 0.65 mm bonded to the lower (upper) metal base of the metal housing at a predetermined position using conductive adhesive. For example, at 300 GHz, r1 is 0.16 mm, and r2, which improves antenna gain, is in the range of 0.4 to 0.7 mm, but r2 is preferably in the range of 0.5 to 0.65 mm. Furthermore, a subterahertz band power amplifier, mixer, and phase shifter chip (not shown) are sequentially bonded to the lower (upper) metal base of the metal housing. After that, the SIW antenna array, power amplifier, mixer, and phase shifter are connected. After that, the SIW antenna array Then, a concave upper (lower) metal cover with a groove larger than the size of the power amplifier, mixer, and phase shifter is placed over it. By bonding these together with an H-shaped intermediate metal component having a groove larger than the size of the SIW antenna array, power amplifier, mixer, and phase shifter, the amplifier-integrated antenna module of the 2nd modification of the 4th embodiment is completed. In order to make the antenna spacing (b) 0.4 mm, the thickness (t2) of the H-shaped intermediate metal component is 0.57 mm and the depth of the grooves on both sides (d2) is 0.2 mm. At this time, the third width (A3) of the H-shaped intermediate metal component is 0.17 mm, which is larger than the air λ / 10. The sides of this metal housing function as metal walls (reflectors).

[0099] Figure 19 illustrates an example where four SIW antennas are arranged in parallel horizontally, and these SIW antenna arrays are stacked vertically in four layers. However, multiple arrays can also be created.

[0100] <Example of antenna module configuration in modified example 3 of the fourth embodiment> Figure 20 shows an example of the configuration of antenna module 1000. Figure 20A is a top view, and Figure 20B is a cross-sectional view. The thermal conductivity of the InP substrate and GaAs substrate on which the subterahertz band power amplifier is fabricated is low (see Table 1 in Figure 21), at 68 and 46 W / mK, respectively. On the other hand, the thermal conductivity of the SiC substrate, which is the dielectric substrate of the SIW antenna array, is high at 490 W / mK, so it can also be used as a heat spreader material. Therefore, by mounting the subterahertz band power amplifier on the SIW antenna array, it is possible to improve the heat dissipation effect of the power amplifier. In addition, instead of the SiC substrate, it is also possible to use high-resistance Si substrates (148 W / mK), GaN substrates (230 W / mK), AlN substrates (340 W / mK), and diamond substrates (2000 W / mK), which have higher thermal conductivity than InP and GaAs substrates, as dielectric substrates. Furthermore, with GaN HEMTs, the SiC substrate, GaN substrate, AlN substrate, and high-resistance Si substrate used for GaN epitaxial crystal growth can be used directly as dielectric substrates. In this embodiment, an example of a transmitting antenna module using a power amplifier is shown, but a receiving antenna module using a low-noise amplifier (LNA) may also be configured.

[0101] By equipping transceivers with substrate-integrated waveguide antennas and antenna array structures, it becomes possible to provide communication system equipment for Beyond 5G / 6G.

[0102] [Other embodiments] Each embodiment may be combined with others. For example, the arrayed antenna may be either antenna 100 or antenna 200, or both. Also, for example, an antenna module or transceiver may be configured using any of antenna 100, antenna 200, antenna array 300, antenna array 400, antenna array 500, and antenna array 600, or a combination thereof.

[0103] Furthermore, the components in each embodiment are not limited to the substances described in the examples. For example, components may be replaced with other substances having similar actions, effects, or properties. [Explanation of Symbols]

[0104] 100: Antenna 200: Antenna 300: Antenna Array 400: Antenna Array 500: Antenna Array 600: Antenna Array 700: Antenna module 800: Antenna module 900: Antenna module 1000: Antenna module

Claims

1. It has a substrate-integrated waveguide section, a radiation section composed of multiple metal strips, and a metal wall. The substrate integrated waveguide section and the radiating section are connected on a dielectric substrate. The metal wall is positioned at a first position at a first distance from the interface where the substrate integrated waveguide section and the radiation section are connected, in the direction of the radiation section, and at a second position at a second distance that is longer than the first distance in the direction of the substrate integrated waveguide section. PCB integrated waveguide antenna.

2. An array antenna having multiple substrate-integrated waveguide antennas, wherein N substrate-integrated waveguide antennas are arranged so as to overlap vertically, and M substrate-integrated waveguide antennas are arranged horizontally, The substrate-integrated waveguide antenna comprises a substrate-integrated waveguide section, a radiating section composed of a plurality of metal strips, and a metal wall. The substrate-integrated waveguide section and the radiating section are connected on a dielectric substrate, and the metal wall is positioned at a second position, which is longer than the first distance, from a first position at a first distance from the interface between the substrate-integrated waveguide section and the radiating section in the direction of the radiating section, to a second position at a second distance in the direction of the substrate-integrated waveguide section. Array antenna.

3. The first distance is the distance within the dielectric substrate that is half the wavelength of the predetermined frequency at a predetermined frequency in which the substrate integrated waveguide portion is in TE10 mode, and the second distance is in the range of 1 / 2-1 / 10 to 1 / 2+1 / 5 of the wavelength of the predetermined frequency in air. A substrate-integrated waveguide antenna according to claim 1.

4. The metal wall is arranged to surround the substrate integrated waveguide section. A substrate-integrated waveguide antenna according to claim 1.

5. The metal wall has an outer circumference with a first width extending from the front and back surfaces of the substrate integrated waveguide and a second width extending from the side surface of the substrate integrated waveguide, and the first width is at least one-tenth of the wavelength of the predetermined frequency in air at a predetermined frequency in which the substrate integrated waveguide is in TE10 mode. A substrate-integrated waveguide antenna according to claim 1.

6. The metal wall has an opening larger than the size of the substrate integrated waveguide section. Any surface of the metal wall is in contact with the substrate integrated waveguide section. A substrate-integrated waveguide antenna according to claim 1.

7. The metal wall has a third width between the substrate integrated waveguide sections of the vertically adjacent substrate integrated waveguide antennas, and the third width is such that at a predetermined frequency in which the substrate integrated waveguide section is in TE10 mode, it is 1 / 10 to 1 / 2 of the wavelength of the predetermined frequency in air. This is the range of the difference between the thickness of the substrate integrated waveguide section and the aforementioned substrate integrated waveguide section. The array antenna according to claim 2.

8. The spacing between adjacent substrate-integrated waveguide antennas is smaller than the wavelength of the predetermined frequency in air at a predetermined frequency in which the substrate-integrated waveguide section is in TE10 mode. The array antenna according to claim 2.

9. The substrate-integrated waveguide antenna has multiple through-via connections, Laterally adjacent substrate-integrated waveguide antennas share a portion of the substrate through-via wiring. The array antenna according to claim 2.

10. The substrate integrated waveguide section has a plurality of substrate through-via connections, The length of the metal strip is the difference between the width of the substrate integrated waveguide section and half the diameter of the substrate through-via wiring, and is within the range of the sum of the width of the substrate integrated waveguide section and half the diameter of the substrate through-via wiring. A substrate-integrated waveguide antenna according to claim 1.

11. The sum of the width and spacing of the metal strip is 1 / 4 of the wavelength of the predetermined frequency within the dielectric substrate at a predetermined frequency in which the substrate integrated waveguide portion is in TE10 mode. The ratio of the width to the spacing of the metal strips decreases from the interface towards the radial portion, changing from a 9:1 ratio to a 1:9 ratio. A substrate-integrated waveguide antenna according to claim 1.

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