Millimeter wave flat plate slot array antenna with filtering function implanted

Abstract

The application discloses a millimeter wave flat plate slot array antenna with a filtering function, and relates to the technical field of radio frequency communication. The copper-based micro coaxial line-quasi-planar waveguide transition structure is connected with the staggered vertical layout cross-coupled millimeter wave filter, and is integrated with the quasi-planar waveguide feed power division network to realize a three-dimensional quasi-planar low-loss integrated feed circuit, and the feed circuit excites the high-mode flat plate slot antenna array through a coupling slot. The application utilizes the multi-layer metal plane and vertical design capability of electrochemical additive technology, breaks through the key problems of low-process-complexity low-loss interconnection integrated transition interface, low-loss miniaturized filtering structure and array antenna remaining limited special-shaped physical space integrated, and meets the actual application requirements of miniaturization and integration of the millimeter wave radio frequency communication system.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology, and in particular to a millimeter-wave planar slot array antenna with embedded filtering function. Background Technology

[0002] With the continuous development of modern wireless communication technology, limited spectrum resources are becoming increasingly congested, and usable frequency bands are becoming increasingly insufficient. Researchers are focusing on millimeter-wave communication systems with higher frequencies and wider bandwidths. Millimeter-wave communication systems offer advantages such as wide usable bandwidth, large channel capacity, and ease of device miniaturization. However, in the millimeter-wave band, the dielectric loss of traditional transmission lines increases, and inter-line coupling and radiation effects become significant, limiting the integration and miniaturization of millimeter-wave systems. Novel transmission lines based on electrochemical additive manufacturing not only possess the advantages of low loss and high inter-line isolation over a wide bandwidth but also feature quasi-planarity, self-encapsulation, and easy interconnection and integration. Therefore, they hold significant potential advantages in the design of integrated and miniaturized millimeter-wave communication systems.

[0003] Filters and antennas, as functional components for frequency selection and radiation, are commonly integrated in millimeter-wave microsystems. On the one hand, the approach of designing and cascading filters and antennas independently is increasingly unable to meet the growing demands of millimeter-wave systems for smaller size and weight, higher electrical performance, and more complex electrical functions. Therefore, integrating millimeter-wave filters within the limited physical space provided by array antennas is of significant practical importance. On the other hand, copper-based microcoaxial millimeter-wave filters cannot be directly tested or interconnected with other transmission line modules. Insufficient research on the design of related interconnection and integration transition interfaces severely restricts the application scenarios of copper-based microcoaxial cables. Summary of the Invention

[0004] This invention addresses the problems of high loss in millimeter-wave bands in traditional dielectric substrate transmission lines, difficulty in integrating and miniaturizing metal cavity waveguides, and circuit redundancy and inter-stage mismatch caused by traditional multifunctional collaborative design methods. Based on copper-based microcoaxial lines, it proposes a design method for millimeter-wave planar slotted array antennas with embedded filtering functions. Taking advantage of the vertical layout of three-dimensional multilayer metal structures, this invention designs capacitive and inductive coupling paths to introduce cross-coupling and generate transmission zeros, proposing a design method for vertically laid-out millimeter-wave filters in limited irregular physical spaces. This invention constructs an interconnection and integration transition interface design method and technology between copper-based microcoaxial lines and quasi-planar metal waveguides, solving the problems of high complexity and high loss in the transition structure. Based on the theory and method of multi-device functional collaborative design, this invention flexibly designs the staggered vertical layout of millimeter-wave filters to fully utilize the remaining irregular space of the array antenna, proposing an integrated design and integration method for high-order mode radiating element antenna arrays and three-dimensional quasi-planar low-loss feed circuits, which is beneficial for realizing lightweight, highly integrated, and high-performance millimeter-wave systems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a millimeter-wave planar slotted array antenna with embedded filtering function, comprising:

[0006] Copper-based microcoaxial line-quasi-planar waveguide transition structure;

[0007] A millimeter-wave filter, wherein a rectangular resonant cavity is disposed thereon and the copper-based micro-coaxial line-quasi-planar waveguide transition structure is directly connected through a quasi-planar waveguide;

[0008] The quasi-planar waveguide-fed power divider network has its input port directly connected to the rectangular resonant cavity of the misaligned vertically arranged cross-coupled millimeter-wave filter;

[0009] The copper-based micro-coaxial line-quasi-planar waveguide transition structure, millimeter-wave filter, and quasi-planar waveguide power divider network are integrated to realize the feeding circuit of the three-dimensional quasi-planar low-loss integrated array antenna.

[0010] A high-order mode planar slotted antenna array is disposed above the feeding circuit, and the feeding circuit excites the high-order mode planar slotted antenna array through the coupling slot.

[0011] Preferably, the feeding circuit excites the high-order mode planar slot antenna array through the coupling slot by: the quasi-planar waveguide feeding power divider network opening a coupling slot on the metal upper wall of the output port to excite the high-order mode planar slot antenna array.

[0012] Preferably, the copper-based microcoaxial-quasi-planar waveguide transition structure includes:

[0013] The inner conductor of the copper-based rectangular microcoaxial line and the outer conductor of the copper-based rectangular microcoaxial line are the input feed lines;

[0014] The double-section cylindrical feed probe is composed of a cylindrical connector and a concentric metal cylinder of different diameters connected vertically, and is connected to the copper-based rectangular micro coaxial inner conductor through the cylindrical connector.

[0015] A quasi-planar rectangular waveguide is excited by a double-section cylindrical feed probe introduced through a shared metal layer opening, enabling the signal to transition from the micro-coaxial waveguide to the rectangular waveguide.

[0016] Several dielectric support bars support the copper-based rectangular micro-coaxial inner conductor.

[0017] Preferably, the outer conductor of the feed line smoothly transitions into a cylindrical cavity at its end, which together with the cylindrical connector of the double-section cylindrical feed probe forms a circular coaxial line.

[0018] Preferably, the staggered vertical layout cross-coupled millimeter-wave filter includes multiple rectangular resonant cavities staggered vertically arranged using the remaining irregular space of the feed network, coupling gaps, coupling windows, and several release holes;

[0019] The multiple rectangular resonant cavities are arranged vertically by sharing a metal layer, and the vertically arranged rectangular resonant cavities are staggered.

[0020] Preferably, the coupling method between the first rectangular resonant cavity and the second rectangular resonant cavity is to perform inductive coupling by opening a rectangular slot in the common metal layer of the two resonators;

[0021] The coupling method between the second rectangular resonant cavity and the third rectangular resonant cavity is that two diaphragms form a coupling window between the two resonators, which serves as the inductive coupling between the two resonators;

[0022] The coupling method between the third and fourth rectangular resonant cavities is the same as that between the first and second rectangular resonant cavities;

[0023] The connection between the fourth rectangular resonant cavity and the first rectangular resonant cavity is that two diaphragms are loaded between the two resonant cavities to form a coupling window, and a mushroom-shaped diaphragm is placed in the middle of the coupling window as a capacitive coupling between the fourth rectangular resonant cavity and the first rectangular resonant cavity.

[0024] Preferably, the order of the main coupling is 1-2-3-4, and the order of the cross coupling is 1-4.

[0025] Preferably, the quasi-planar waveguide-fed power divider network comprises n stages with a total of 2 n -1 H-plane waveguide T-junction, wherein the single H-plane T-junction includes an input waveguide, an output waveguide, a diaphragm, a trapezoidal inductive slot, and several release holes.

[0026] Preferably, the high-order mode planar slotted antenna array includes 16 slotted antenna elements, which are arranged symmetrically and at equal intervals, and include a feed waveguide, a coupling slot, a metal cavity, and a radiating slot.

[0027] Preferably, the feed waveguide is the output port of the last stage T-junction of the power divider network, and the TE connection to the metal cavity is achieved through the coupling gap. 201 The excitation mode is such that the metal cavity is divided into four parts by the cavity wall, and a radial slit is opened on the upper metal wall of each of the four cavities. The radial slit is close to the four corners of the metal cavity in the horizontal direction.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. This invention proposes an interconnection and integration transition interface between a copper-based microcoaxial waveguide and a quasi-planar metallic waveguide. By utilizing a double-section cylindrical feed probe, good mode conversion and impedance matching of the transition structure are achieved, solving the problems of high complexity and high loss of the transition structure.

[0030] 2. This invention combines the advantages of a vertical layout of a three-dimensional multilayer metal structure, designs capacitive and inductive coupling paths to introduce cross-coupling and generate transmission zeros, and proposes a millimeter-wave filter with a staggered vertical layout design. This filter achieves excellent bandpass characteristics with high selectivity and low loss while being implanted in a limited irregular physical space.

[0031] 3. This invention designs a quasi-planar waveguide-fed power divider network using a 4-stage H-plane T-junction. The proposed H-plane T-junction loading diaphragm structure and trapezoidal inductive slot structure improve the return loss of the power divider network and expand its bandwidth.

[0032] 4. This invention proposes to excite a metal cavity TE via a coupling gap. 201 Using the method of mode, a high-order mode radiating antenna element was designed, and based on this, a high-gain, high-efficiency, low-profile high-order mode radiating element antenna array was realized.

[0033] 5. Based on the theory and method of multi-device functional collaborative design, this invention flexibly designs the staggered vertical layout of millimeter-wave filters to make full use of the remaining irregular space of the array antenna. It not only realizes the integrated design of high-order mode radiating element antenna array and three-dimensional quasi-planar low-loss feed circuit structure, but also establishes a functional integrated design method and technology for millimeter-wave filters and high-performance antennas based on copper-based micro coaxial lines. Attached Figure Description

[0034] Figure 1 This is a general schematic diagram of the millimeter-wave planar slot array antenna with the filtering function embedded in this invention;

[0035] Figure 2 This is a schematic diagram of the vertically arranged cross-coupled millimeter-wave filter in this invention;

[0036] Figure 3 These are the S-parameter simulation results of the vertically arranged cross-coupled millimeter-wave filter in this invention;

[0037] Figure 4 This is a schematic diagram of the interconnection and integration transition interface between the copper-based microcoaxial waveguide and the quasi-planar metallic waveguide in this invention;

[0038] Figure 5 These are the S-parameter simulation results of the interconnection and integration transition interface between the copper-based microcoaxial and quasi-planar metallic waveguides in this invention.

[0039] Figure 6This is a schematic diagram of the H-plane T-junction and the S-parameter simulation results in this invention;

[0040] Figure 7 This is a schematic diagram and simulation results of the return loss of the high-order mode planar slot antenna element in this invention;

[0041] Figure 8 This is the simulation result of the radiation pattern of the high-order mode planar slot antenna element in this invention;

[0042] Figure 9 The return loss of the millimeter-wave planar slot array antenna with the filtering function embedded in this invention;

[0043] Figure 10 This is the radiation pattern of the millimeter-wave planar slot array antenna with the filtering function embedded in this invention. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be understood in the description of this invention that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0046] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0047] For the purpose of understanding and explanation, the millimeter-wave planar slot array antenna with embedded filtering function provided in the embodiments of the present invention will be described in detail below.

[0048] Figure 1 (a) is a 100-figure diagram of a copper-based microcoaxial line-quasi-planar waveguide transition structure. Figure 1 (b) is a schematic diagram of the whole. Figure 1 (c) is a diagram of a staggered vertical layout cross-coupled millimeter-wave filter. Figure 1 (d) is a 300-degree diagram of a quasi-planar waveguide-fed power divider network. Figure 1 (e) is a diagram of a high-order planar slotted antenna array 400.

[0049] Please refer to Figures 1-10 As shown, this invention relates to a planar slotted array antenna with embedded filtering functionality. The antenna array includes a copper-based micro-coaxial line-quasi-planar waveguide transition structure 100, a staggered vertical layout cross-coupled millimeter-wave filter 200, a quasi-planar waveguide feed power divider network 300, and a high-order mode planar slotted antenna array 400. The copper-based micro-coaxial line-quasi-planar waveguide transition structure 100 connects to the staggered vertical layout cross-coupled millimeter-wave filter 200 and integrates with the quasi-planar waveguide feed power divider network 300 to realize a three-dimensional quasi-planar low-loss integrated array antenna feed circuit. The high-order planar slotted antenna array 400 is positioned above the feed circuit, and the feed circuit excites the high-order planar slotted antenna array 400 through coupling slots. The array antenna and its feed circuit are designed using chemical additive manufacturing technology with micro / nano fabrication processes.

[0050] Figure 4 (a) is a schematic diagram of the interconnection and integration transition interface between copper-based microcoaxial and quasi-planar metallic waveguides. Figure 4 (b) is a partial enlarged view of the interconnect integration transition interface.

[0051] Please refer to Figures 1-10 As shown, the copper-based microcoaxial line-quasi-planar waveguide transition structure 100 includes a copper-based rectangular microcoaxial outer conductor 101, a copper-based rectangular microcoaxial inner conductor 102, two-section cylindrical feed probes 104, 105, and 106, a quasi-planar rectangular waveguide 107, and several dielectric support strips 103. The copper-based rectangular microcoaxial outer conductor 101 and inner conductor 102 use 6-10 layers of metal to jointly form the 50Ω input feed line of the transition structure. The rectangular waveguide 107 uses 1-6 layers of metal. The copper-based rectangular microcoaxial outer conductor and inner conductor, as the input feed line, transmit electromagnetic waves from the copper-based microcoaxial line to the rectangular waveguide through openings in the shared metal layer. Several release holes 108 of the same size are periodically opened on the outer wall of the copper-based microcoaxial outer conductor and the rectangular waveguide to release photoresist. The size of the release holes is 0.2mm × 0.2mm × 0.1mm. The support strips are used to support the inner conductor.

[0052] Please refer to Figures 1-10As shown, the inner conductor 102 of the copper-based rectangular micro-coaxial cable has a width of 0.19 mm and a height of 0.1 mm. The horizontal spacing between the inner and outer conductors is 0.13 mm. The inner conductor of the feed line is connected to the cylindrical connector 104 of the double-section cylindrical feed probe. This connector has a radius of 0.115 mm and a height of 0.3 mm, and is perpendicularly connected to a concentric metal cylinder of different diameters to form the double-section cylindrical feed probe 105. This metal cylinder has a radius of 0.25 mm and a height of 0.2 mm. Through this double-section cylindrical feed probe 105, the transition structure can achieve good mode conversion and smooth impedance transition. The outer conductor of the feed line smoothly transitions to a cylindrical cavity at the end. The radius of this cylindrical cavity is 0.77 mm, which, together with the cylindrical connector of the double-section cylindrical feed probe, forms a section of circular coaxial line. The rectangular waveguide 107 has a cross-sectional width of 1.75 mm, a height of 0.4 mm, and a metal outer wall width of 0.1 mm.

[0053] Please refer to Figures 1-10 As shown, the dual-section cylindrical feed probe 105 achieves excellent mode conversion and impedance matching from a copper-based rectangular microcoaxial line to a rectangular waveguide. Within the 92-96 GHz frequency band, the transition structure exhibits a return loss better than 23.8 dB, an insertion loss better than 0.1068 dB, and an insertion loss of 0.0899 dB at the center frequency @ 94 GHz.

[0054] Figure 2 (a) is an enlarged view of a vertically arranged cross-coupled millimeter-wave filter. Figure 2 (b) shows the rectangular resonant cavity and coupling gap.

[0055] Please refer to Figures 1-10 As shown, the staggered vertical layout cross-coupled millimeter-wave filter 200 includes four staggered vertically arranged rectangular resonant cavities 201, 202, 203, and 204, two coupling slots 205 and 206, two coupling windows 207 and 208, and several release holes 209. The rectangular waveguide resonant cavities utilize the same fabrication process as copper-based microcoaxial cables. By removing the inner conductor of the rectangular microcoaxial cable and widening the lateral dimension of the outer conductor, a high-Q, low-loss, and highly integrated metal waveguide resonant cavity is achieved. The first rectangular resonator 201 and the fourth rectangular resonator 204 use 1-6 layers of metal, with a fixed height of 400 μm, a cross-sectional width of 1.75 mm, and a cavity length of 3.25 mm. The second rectangular resonator 202 and the third rectangular resonator 203 use 6-11 layers of metal, with a fixed height of 400 μm, a cross-sectional width of 1.75 mm, and a cavity length of 3 mm. The four resonant cavities are vertically arranged by sharing a sixth metal layer, while the two resonant cavities arranged vertically are staggered by 275mm. Release holes 209 are periodically opened on the outer wall of the resonant cavities to release the photoresist, and the size of the release holes is 0.2mm×0.2mm×0.1mm.

[0056] Please refer to Figures 1-10 As shown, the coupling method between the first rectangular resonant cavity 201 and the second rectangular resonant cavity 202 is inductive coupling via a 6th layer metal slotted groove 205 shared by the two resonant cavities, wherein the length of the slotted groove is 1 mm and the width is 0.34 mm; the coupling method between the second rectangular resonant cavity 202 and the third rectangular resonant cavity 203 is inductive coupling via a coupling window 207 formed by two diaphragms between the two resonant cavities, wherein the width of the coupling window is 0.9 mm; the coupling method between the third rectangular resonant cavity 203 and the fourth rectangular resonant cavity 202 .... The coupling method between the four rectangular resonators 204 is the same as that between the first rectangular resonator 201 and the second rectangular resonator 202. The connection method between the fourth rectangular resonator 204 and the first rectangular resonator 201 is that two diaphragms are loaded between the two resonators to form a coupling window 208. Mushroom-shaped diaphragms 210 and 211 are placed in the middle of the coupling window. The width of the coupling window is 0.9 mm. The mushroom-shaped diaphragm is composed of diaphragm 1 connected to the metal outer wall of the resonator, which serves as the capacitive coupling between the fourth rectangular resonator and the first rectangular resonator. The main coupling sequence is 1-2-3-4, and the cross coupling sequence is 1-4. The filter generates two transmission zeros through cross coupling to improve the passband selectivity. Diaphragm 210 and vertically connected diaphragms 2 and 212 are used. The height of diaphragm 1 is 200 μm and the side length is 0.2 mm × 0.2 mm. The height of diaphragm 2 is 0.1 mm and the side length is 0.775 × 0.45 mm.

[0057] Please refer to Figures 1-10 As shown, the staggered vertical layout cross-coupled millimeter-wave filter has a center frequency of 94.05 GHz, a 3dB bandwidth of 3.76%, and an operating frequency range of 92.28-95.82 GHz. The insertion loss at the center frequency is 0.5377 dB, the return loss is better than 21.3 dB in the range of 92.56-95.40 GHz, the out-of-band rejection at 90 GHz reaches 36.5 dB, and the out-of-band rejection at 98 GHz reaches 31.0 dB.

[0058] Quasi-planar waveguide-fed power divider network, including n stages for a total of 2 n -1 H-plane waveguide T-junction. A single H-plane T-junction includes an input waveguide, an output waveguide, a diaphragm, a trapezoidal inductive slot, and several release holes. The diaphragm structure is loaded at the input end of the H-plane T-junction, improving the return loss of the T-junction; the trapezoidal inductive slot is introduced on the inner wall between the two output ports, further widening the bandwidth of the power divider.

[0059] Figure 6 (a) is a schematic diagram of an H-plane T-junction. Figure 6 (b) is a graph showing the simulation results of S-parameters.

[0060] Please refer to Figures 1-10As shown, the quasi-planar waveguide-fed power divider network 300 uses a 1-6 layer metal design, including 15 H-plane waveguide T-junctions 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312, 313, 314, and 315 in 4 levels. Each H-plane T-junction includes an input waveguide 316, an output waveguide 317 and 318, diaphragms 319 and 320, a trapezoidal inductive slot 321, and several release holes.

[0061] Please refer to Figures 1-10 As shown, the H-plane T-junction adds diaphragm structures 319 and 320 at its input end to improve the return loss of the T-junction. The width of the diaphragm is 0.052 mm and the length is 0.3 mm. At the same time, a trapezoidal inductive slot 321 is introduced on the inner wall between the two output ports of the H-plane T-junction, further widening the bandwidth of the power divider. The upper base of the trapezoidal slot is 0.08 mm long, the lower base is 0.43 mm long, and the distance between the two bases is 0.85 mm.

[0062] Please refer to Figures 1-10 As shown, the H-plane T-junction exhibits a return loss better than 22.7 dB and an amplitude imbalance of less than 0.1 dB in the 92-96 GHz range.

[0063] Please refer to Figures 1-10 As shown, the high-order mode planar antenna array 400 uses a 6-11 layer metal design, including 16 2×2 slot antenna elements 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, 413, 414, 415, and 416. The slot antenna elements are arranged in a 4×4 symmetrical and equally spaced manner, and the 16 antenna elements correspond one-to-one with the output ports of the quasi-planar waveguide-fed power divider network.

[0064] Figure 7 (a) is a schematic diagram of a high-order mode planar slot antenna element. Figure 7 (b) shows the simulation results of return loss.

[0065] Please refer to Figures 1-10 As shown, the high-order mode planar slot antenna element includes a feed waveguide 417, a coupling slot 418, a metal cavity 419, and radiation slots 420, 421, 422, and 423. The feed waveguide 417 is the output port of the last stage T-junction of the power divider network. The magnetic field energy is coupled to the metal cavity through the coupling slot 418. The metal cavity is divided into four parts by the cavity wall. A radiation slot 420, 421, 422, and 423 are opened on the upper metal wall of each part to radiate electromagnetic waves.

[0066] Please refer to Figures 1-10As shown, the coupling gap 418 is located at the center of the metal cavity directly opposite the sixth metal layer, with a length of 1.75 mm and a width of 0.4 mm. The magnetic field at the coupling gap is distributed along its long side, exciting magnetic fields in the same direction on both sides, thus achieving TE coupling of the metal cavity. 201 Incentives based on patterns.

[0067] Please refer to Figures 1-10 As shown, two sets of diaphragms extend from the center of the four sides of the metal cavity, dividing the cavity into four parts. The metal cavity is 5.21 mm long and 3.45 mm wide. The diaphragms distributed along the x-axis are 0.3 mm long and 0.4 mm wide, and the diaphragms distributed along the y-axis are 1.6 mm long and 0.4 mm wide. A radiating slot 420, 421, 422, and 423 are opened on the upper metal wall of each of the four cavities. These radiating slots are positioned horizontally close to the four corners of the metal cavity, maximizing the cutting of the surface current of the metal cavity and better achieving strong radiation from the slot antenna. The radiating slot is 2.29 mm long and 0.85 mm wide.

[0068] Figure 8 (a) is the return loss of the millimeter-wave planar slot array antenna with filtering function implanted when Phi = 0°. Figure 8 (b) Return loss of millimeter-wave planar slot array antenna with filtering function implanted when Phi = 90°.

[0069] Please refer to Figures 1-10 As shown, the high-order mode planar slotted antenna element exhibits a return loss better than 20dB in the 90-100GHz range. At the center frequency of the antenna operation at 94GHz, the gain of a single antenna reaches 13.56dB, with a main lobe gain of 13.51dB and a sidelobe gain of 5.06dB in the Phi=0° plane; and a main lobe gain of 13.51dB and a sidelobe gain of 2.35dB in the Phi=90° plane, indicating a relatively low antenna sidelobe.

[0070] Figure 10 (a) Radiation pattern of a millimeter-wave planar slotted array antenna with filtering function implanted when Phi = 0°. Figure 10 (b) Radiation pattern of millimeter-wave planar slot array antenna with filtering function implanted when Phi = 0°.

[0071] Please refer to Figures 1-10 As shown, the millimeter-wave planar slotted array antenna with embedded filtering function exhibits a return loss better than 10dB in the frequency range of 92.36-95.5GHz and demonstrates good frequency selectivity. At the center frequency of 94GHz, the antenna array has a main lobe gain of 25.52dB and a maximum sidelobe gain of 9.96dB in the Phi=90° plane; and a main lobe gain of 25.52dB and a maximum sidelobe gain of 9.26dB in the Phi=0° plane.

[0072] In summary, this invention proposes an interconnection and integration transition interface between a copper-based microcoaxial cable and a quasi-planar metallic waveguide, solving the problems of high complexity and high loss in the transition structure. The designed millimeter-wave filter with a staggered vertical layout achieves excellent bandpass characteristics with high selectivity and low loss while being implanted in a limited, irregularly shaped physical space. The proposed H-plane T-junction loaded diaphragm structure and trapezoidal inductive slot structure improve the return loss of the power divider network and extend its bandwidth. The proposed method of exciting a metallic cavity TE via a coupling slot is also presented. 201 The method of mode-based design realizes a high-gain, high-efficiency, and low-profile high-order mode radiating element antenna array; based on the theory and method of multi-device functional collaborative design, the staggered vertical layout of millimeter-wave filters is flexibly designed to make full use of the remaining irregular space of the array antenna, realizing the integrated design of high-order mode radiating element antenna array and three-dimensional quasi-planar low-loss feed circuit structure, which is conducive to realizing lightweight, highly integrated, and high-performance millimeter-wave systems.

[0073] The above-described embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited thereto. Any simple changes or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the scope of the technology disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. A millimeter-wave planar slotted array antenna with embedded filtering function, characterized in that, include: Copper-based microcoaxial line-quasi-planar waveguide transition structure (100); A millimeter-wave filter (200) has a rectangular resonant cavity disposed thereon, which is directly connected to the copper-based micro-coaxial line-quasi-planar waveguide transition structure (100) through a quasi-planar waveguide; The input port of the quasi-planar waveguide-fed power divider network (300) is directly connected to the rectangular resonant cavity of the millimeter-wave filter (200) which is cross-coupled in a staggered vertical layout; The copper-based micro-coaxial line-quasi-planar waveguide transition structure (100), millimeter-wave filter (200), and quasi-planar waveguide power divider network (300) are integrated to realize the feeding circuit of the three-dimensional quasi-planar low-loss integrated array antenna. A high-order mode planar slotted antenna array (400) is disposed above the feeding circuit, and the feeding circuit excites the high-order mode planar slotted antenna array (400) through the coupling slot (418); The copper-based microcoaxial-quasi-planar waveguide transition structure (100) includes: The inner conductor (101) of the copper-based rectangular micro-coaxial line and the outer conductor (102) of the copper-based rectangular micro-coaxial line are the input feed lines; The double-section cylindrical feed probe is composed of a cylindrical connector and a concentric metal cylinder of different diameters connected vertically, and is connected to the copper-based rectangular micro coaxial inner conductor (101) through the cylindrical connector. The quasi-planar rectangular waveguide (106) is excited by a double-section cylindrical feed probe introduced through a common metal layer opening, realizing the transition of signal from micro-coaxial to rectangular waveguide; Several dielectric support strips (103) support the copper-based rectangular micro-coaxial inner conductor (101); The staggered vertical layout cross-coupled millimeter-wave filter (200) includes multiple rectangular resonant cavities staggered vertically arranged using the remaining irregular space of the feed network, coupling slots, coupling windows, and several release holes (209) for releasing photoresist. The multiple rectangular resonant cavities are vertically arranged by sharing a metal layer, and the vertically arranged rectangular resonant cavities are staggered; among the multiple rectangular resonant cavities: The coupling method between the first rectangular resonant cavity and the second rectangular resonant cavity is to perform inductive coupling by opening a rectangular slot in the common metal layer of the two resonators; The coupling method between the second rectangular resonant cavity and the third rectangular resonant cavity is that two diaphragms form a coupling window between the two resonators, which serves as the inductive coupling between the two resonators; The coupling method between the third and fourth rectangular resonant cavities is the same as that between the first and second rectangular resonant cavities; The connection between the fourth rectangular resonant cavity and the first rectangular resonant cavity is that two diaphragms are loaded between the two resonant cavities to form a coupling window, and a mushroom-shaped diaphragm is placed in the middle of the coupling window as a capacitive coupling between the fourth rectangular resonant cavity and the first rectangular resonant cavity. The quasi-planar waveguide-fed power divider network (300) includes n stages with a total of 2 n -1 H-plane waveguide T-junction, wherein the single H-plane T-junction includes an input waveguide, an output waveguide, a diaphragm, a trapezoidal inductive slot, and several release holes; The high-order mode planar slot antenna array (400) includes 16 slot antenna elements, which are arranged symmetrically and at equal intervals, including a feed waveguide, a coupling slot, a metal cavity, and a radiation slot.

2. The millimeter-wave planar slotted array antenna with embedded filtering function as described in claim 1, characterized in that, The feeding circuit excites the high-order mode planar slot antenna array (400) through the coupling slot (418). Specifically, the quasi-planar waveguide feeding power divider network (300) excites the high-order mode planar slot antenna array (400) by opening a coupling slot on the metal upper wall of the output port.

3. The millimeter-wave planar slotted array antenna with embedded filtering function as described in claim 1, characterized in that, The copper-based rectangular micro-coaxial outer conductor (102) smoothly transitions into a cylindrical cavity at its end, which together with the cylindrical connector of the double-section cylindrical feed probe forms a circular coaxial line.

4. The millimeter-wave planar slotted array antenna with embedded filtering function as described in claim 1, characterized in that, The order of primary coupling is 1-2-3-4, and the order of cross coupling is 1-4.

5. The millimeter-wave planar slotted array antenna with embedded filtering function as described in claim 1, characterized in that, The feed waveguide is the output port of the last stage T-junction of the power divider network, and the TE connection to the metal cavity is achieved through the coupling gap. 201 The excitation mode is such that the metal cavity is divided into four parts by the cavity wall, and a radial slit is opened on the upper metal wall of each of the four cavities. The radial slit is close to the four corners of the metal cavity in the horizontal direction.

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