Compact millimeter wave high-gain filtering antenna array

Abstract

The invention provides a compact millimeter wave high-gain filtering antenna array, which belongs to the field of radio frequency communication and sequentially comprises a patch array antenna, an upper dielectric substrate, a middle metal surface, a lower dielectric substrate and a lower metal surface from top to bottom. The substrate integrated waveguide resonant cavity is formed by enclosing a plurality of metallized through holes which are periodically distributed, the substrate integrated waveguide resonant cavity comprises a first cavity, a second cavity and a third cavity, the first cavity, the second cavity and the third cavity are symmetrical about the central axis of the lower-layer dielectric substrate, a coupling window is arranged between every two adjacent cavities, and the first cavity, the second cavity and the third cavity are communicated through the coupling window. The middle metal surface is provided with rectangular slot coupling grooves which are symmetrical about the central axis of the lower-layer dielectric substrate, the positions of the rectangular slot coupling grooves correspond to the positions of the patch array antennas, and a coplanar waveguide transmission line is etched on the lower-layer metal surface. The filtering antenna array is low in loss, low in cost, easy to process and convenient for plane integration.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency communication technology, and in particular to a compact millimeter wave high-gain filtering antenna array. Background Art

[0002] With the rapid development of wireless communication technology, the millimeter wave frequency band has become an indispensable part of the 5G communication system due to its unique bandwidth resources, and is regarded as a key frequency band for the future 6G communication system. The use of this frequency band has brought revolutionary changes to the field of wireless communication, significantly improving the data transmission rate and system capacity.

[0003] The design of the radio frequency (RF) front end plays a decisive role in ensuring the performance and reliability of the communication system. Antennas and filters are key components of the RF front end, and their design directly affects the quality of signal reception and transmission. The filter antenna integrates the radiation function of the antenna and the filtering function of the filter in one component, which reduces the system volume, improves the integration level, and reduces the cost. It meets the requirements of RF front-end integration and miniaturization and is suitable for compact mobile devices. Most filter antenna arrays are implemented with microstrip feeding structures. They may perform well at low frequencies, but they will inevitably suffer from huge insertion losses at millimeter wave frequencies. Although some filter arrays use metal waveguide structures to alleviate the problem of signal loss, this structure is not easy to integrate with planar circuits. In addition, the processing cost of metal waveguide structures is relatively high, especially in applications in the millimeter wave band, where extremely high processing accuracy is required.

[0004] Therefore, the core issue of current research focuses on how to design a filtering antenna that can achieve the characteristics of low loss, low cost, easy processing and easy planar integration without adding additional filtering circuits. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a compact millimeter-wave high-gain filtering antenna array, which achieves the characteristics of low loss, low cost, easy processing and convenient planar integration of the filtering antenna array without adding additional filtering circuits.

[0006] The present invention solves the above technical problems through the following technical solutions: a compact millimeter wave high-gain filtering antenna array, which comprises, from top to bottom, a patch array antenna, an upper dielectric substrate, an intermediate metal surface, a lower dielectric substrate, and a lower metal surface, wherein a substrate integrated waveguide resonant cavity is arranged in the lower dielectric substrate, and the substrate integrated waveguide resonant cavity is surrounded by a plurality of periodically distributed metallized through holes, and the substrate integrated waveguide resonant cavity comprises a first cavity, a second cavity, and a third cavity, wherein the first cavity, the second cavity, and the third cavity are symmetrical about the central axis of the lower dielectric substrate, and coupling windows are arranged between adjacent cavities, and a rectangular slot coupling groove symmetrical about the central axis of the lower dielectric substrate is opened on the intermediate metal surface, and the position of the rectangular slot coupling groove corresponds to the position of the patch array antenna, and a coplanar waveguide transmission line is etched on the lower metal surface.

[0007] Preferably, the first cavity and the second cavity resonate in TE101 mode, and the third cavity resonates in TE201 mode.

[0008] Preferably, the substrate integrated waveguide resonant cavity is a SIW cavity, the TE201 mode has two field components with the same amplitude and opposite phases, and the third cavity resonating in the TE201 mode utilizes the inherent modal energy distribution characteristics of the SIW cavity to achieve four-way signal output.

[0009] Preferably, the patch array antenna is a 2×2 radiation patch structure, four radiation patches are symmetrically distributed above the third cavity, and the rectangular slot coupling slot is located below the radiation patch.

[0010] Preferably, the rectangular gap coupling slots are matched by electrical coupling.

[0011] Preferably, the coplanar waveguide transmission line is carved from the edge of the lower metal surface and extends into the interior of the substrate integrated waveguide resonant cavity.

[0012] Preferably, two axisymmetric L-shaped gaps are etched in the area of ​​the lower metal surface located within the metallized through-hole array, and the edges of the L-shaped gaps in contact with the edge of the lower metal surface are arranged parallel to the edge of the lower metal surface. The lower metal surface area between the two axisymmetric L-shaped gaps and the two L-shaped gaps constitute a coplanar waveguide transmission line, and the substrate integrated waveguide resonant cavity is fed through the coplanar waveguide transmission line.

[0013] Preferably, the upper dielectric substrate and the lower dielectric substrate are made of Taconic TLY, both of which have a relative dielectric constant of 2.2 and a loss tangent of 0.0009.

[0014] Preferably, the shortest distance between the edge of the radiation patch away from the coplanar waveguide transmission line and the edge of the rectangular slot coupling slot at its corresponding position is 0.665 mm, and the shortest distance between the edge of the radiation patch close to the coplanar waveguide transmission line and the edge of the rectangular slot coupling slot at its corresponding position is 0.565 mm.

[0015] Preferably, the radiation patch is a square patch with a thickness of 0.035 mm and a side length of 3.2 mm, the edge spacing between two radiation patches symmetrical about the central axis of the upper dielectric substrate is 6.8 mm, and the edge spacing between two radiation patches on the same side of the central axis is 6.1 mm.

[0016] The advantages provided by the present invention are:

[0017] (1) The present invention adopts a laminated design to reduce the size of the RF component and has the advantage of high integration. The feed cavity adopts a SIW structure, which has the advantages of low radiation loss, high quality factor, small size, easy integration, etc., and can effectively suppress interference signals and improve transmission quality. The antenna part adopts an array patch antenna structure with high gain, simple design, compact antenna array structure, easy processing, and easy integration. It is consistent with the trend of miniaturization and high integration of future systems and has broad application potential in modern communications, radar detection, satellite communications, radio monitoring and other fields. The design of the filter antenna is based on the comprehensive design of the filter antenna. The antenna is used as the last stage of the filter. The antenna is also a part of the filter resonance while radiating. Compared with the independent assembly of individual devices in the system, this integrated design reduces the addition of additional components and additional circuit assistance, and has the advantages of high integration and compact structure.

[0018] (2) The filtering part of the present invention is designed to resonate in the TE101 mode by the first cavity and the second cavity, and the third cavity is symmetrically distributed and designed to resonate in the TE201 mode, and the resonance frequency is 27 GHz, wherein the TE201 mode has two field vectors with the same amplitude and opposite phase. The two TE101 modes and the TE201 mode cavity with two field vectors are reasonably coupled to generate a third-order bandpass response of the passband. By coupling and mixing the two modes of SIW resonant cavities, the power distribution four-way signal output and the filtering response are realized simultaneously.

[0019] (3) The antenna part of the present invention adopts a 2×2 radiation patch structure. The four units form an array to improve the gain and directivity of the antenna. It is easy to process, small in size, and low in cost, which is consistent with the trend of future systems towards miniaturization and high integration. It effectively addresses the problem of adding additional components and excessive volume when integrating a single device in current RF devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A three-dimensional diagram of a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0021] Figure 2 A front view of a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0022] Figure 3 A top view of a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0023] Figure 4 A top view of a patch array antenna in a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0024] Figure 5 A top view of the middle metal surface in the compact millimeter wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0025] Figure 6 A top view of a lower metal surface in a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0026] Figure 7 An S-parameter curve diagram of a compact millimeter-wave high-gain filtering antenna array provided by an embodiment of the present invention;

[0027] Figure 8 A radiation gain curve diagram of a compact millimeter-wave high-gain filtering antenna array provided in an embodiment of the present invention;

[0028] Fig. 9 The radiation pattern of the compact millimeter-wave high-gain filtering antenna array at 27 GHz provided by an embodiment of the present invention;

[0029] In the figure: 10 upper dielectric substrate, 20 lower dielectric substrate, 21 first cavity, 22 second cavity, 23 third cavity, 30 middle metal surface, 31 rectangular slot coupling groove, 40 lower metal surface, 41 L-shaped slot, 50 metallized through hole, 60 radiation patch. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is clearly and completely described below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figure 1 and Figure 2As shown, this embodiment provides a compact millimeter wave high-gain filtering antenna array, including two layers of Taconic TLY upper dielectric substrate 10, lower dielectric substrate 20, both with a thickness h1 of 0.254 mm, and an intermediate metal surface 30 and a lower metal surface 40 of the same size as the dielectric substrate. The relative dielectric constants of the upper dielectric substrate 10 and the lower dielectric substrate 20 are both 2.2, and the loss tangent is 0.0009. The thickness h2 of the intermediate metal surface 30 and the lower metal surface 40 is 0.035 mm.

[0032] A plurality of periodically distributed metallized through holes 50 are etched in the lower dielectric substrate 20. The plurality of metallized through holes 50 penetrate the lower dielectric substrate 20 to form a metal wall of a substrate-integrated waveguide resonant cavity. The substrate-integrated waveguide resonant cavity includes a first cavity 21, a second cavity 22, and a third cavity 23. There are coupling windows between adjacent cavities. The size of each coupling window is flexibly adjusted according to the coupling amount requirements of each cavity structure, such as Figure 3 As shown, in this embodiment, the coupling window width w12 between the first cavity 21 and the second cavity 22 is 2.3 mm, the coupling window width w23 between the second cavity 22 and the third cavity 23 is 2.46 mm, the first cavity 21, the second cavity 22, and the third cavity 23 are symmetrical about the central axis of the lower dielectric substrate 20, the length l1 of the first cavity 21 is 5.99 mm, the width w1 is 4.81 mm, the length l2 of the second cavity 22 is 5.69 mm, the width w2 is 4.84 mm, the length l3 of the third cavity 23 is 12.22 mm, the diameter of the metallized through hole 50 is 0.3 mm, Figure 3 The starting positions of the dimensions l1, l2, l3, l4, w1, and w2 are all the centers of the metallized through holes.

[0033] The patch array antenna covers the upper surface of the upper dielectric substrate 10 and is symmetrical about the central axis of the upper dielectric substrate 10. In this embodiment, the patch array antenna is a 2×2 radiation patch structure, and four radiation patches 60 are symmetrically distributed above the third cavity 23. Figure 4 The radiation patch 60 is a square patch with a thickness of 0.035 mm and a side length wp of 3.2 mm. The edge spacing dy of two radiation patches 60 symmetrical about the central axis of the upper dielectric substrate 10 is 6.8 mm, and the edge spacing dx of two radiation patches 60 located on the same side of the central axis of the upper dielectric substrate 10 is 6.1 mm.

[0034] The middle metal surface 30 is located on the lower surface of the upper dielectric substrate 10 and the upper surface of the lower dielectric substrate 20. Figure 5As shown, the middle metal surface 30 is provided with a rectangular slot coupling groove 31 symmetrical about the central axis of the dielectric substrate. The position of the rectangular slot coupling groove 31 is set corresponding to the position of the radiation patch 60. The length of the rectangular slot coupling groove 31 is ls and the width is ws. The magnetic field energy in the substrate integrated waveguide resonant cavity is coupled into the antenna array composed of the radiation patch 60 and the upper dielectric substrate 10 through the rectangular slot coupling groove 31. By adjusting the length ls and the width ws of the rectangular slot coupling groove 31, the impedance matching between the resonant cavity filter part and the antenna part can be well adjusted. The shortest distance between the edge of the radiation patch 60 away from the coplanar waveguide transmission line and the edge of the rectangular slot coupling groove 31 at the corresponding position is w1′=0.665mm, and the shortest distance between the edge of the radiation patch 60 close to the coplanar waveguide transmission line and the edge of the rectangular slot coupling groove 31 at the corresponding position is w2′=0.565mm. The rectangular slot coupling groove 31 adopts an electrical coupling method to achieve better matching.

[0035] Continue reading Figure 1 The lower metal surface 40 covers the lower surface of the lower dielectric substrate 20, and a coplanar waveguide transmission line extending into the substrate integrated waveguide resonant cavity is engraved from the edge of the lower metal surface 40, such as Figure 6 As shown, the area of ​​the lower metal surface 40 located within the array of metallized through holes 50 is etched with two L-shaped gaps 41 symmetrical about the central axis of the lower metal surface 40, and the edges of the L-shaped gaps 41 that are in contact with the edge of the lower metal surface 40 are arranged parallel to the edge of the lower metal surface 40. The lower metal surface area between the two axially symmetrical L-shaped gaps and the two L-shaped gaps form a coplanar waveguide transmission line, and the substrate integrated waveguide resonant cavity is fed through the coplanar waveguide transmission line.

[0036] Continue reading Figure 6 The characteristic impedance of the coplanar waveguide transmission line is 50 ohms, the total width is w0, and the total length is l0. By adjusting the total width w0 and the total length l0 of the coplanar waveguide transmission line, the impedance matching of the antenna can be adjusted.

[0037] The materials of the middle metal surface 30, the lower metal surface 40, the metallized through hole 50, and the radiation patch 60 are all copper. The size of the entire filtering antenna array can be designed to be 16mm×18mm×0.678mm, which can be widely used in various communication equipment such as 5G base stations and mobile communication terminals. It conforms to the trend of miniaturization of radio frequency devices and can effectively solve the problems of requiring additional components and excessive size when integrating a single device into the system.

[0038] The specific structural geometric parameters are as follows:

[0039] Wherein, h1 is the thickness of the dielectric substrate, h2 is the thickness of the metal surface, w12 is the coupling window width between the first cavity 21 and the second cavity 22, w23 is the coupling window width between the second cavity 22 and the third cavity 23, l1 and w1 are the length and width of the first cavity 21 respectively, l2 and w2 are the length and width of the second cavity 22 respectively, l3 is the length of the third cavity 23, wp is the side length of the radiation patch, dy is the edge spacing of the two radiation patches 60 symmetrical about the central axis of the upper dielectric substrate 10, dx is the edge spacing of the two radiation patches 60 located at the corresponding positions of the same cavity, ls and ws are the length and width of the rectangular slot coupling slot 31 respectively, w1′ is the shortest distance between the edge of the radiation patch 60 away from the coplanar waveguide transmission line and the edge of the rectangular slot coupling slot 31 at its corresponding position, w2′ is the shortest distance between the edge of the radiation patch 60 close to the coplanar waveguide transmission line and the edge of the rectangular slot coupling slot 31 at its corresponding position, and l0 and w0 are the total length and total width of the coplanar waveguide transmission line respectively.

[0040] The compact millimeter-wave high-gain filtering antenna array of the present invention operates in the n258 frequency band, has good filtering characteristics, and has a high gain. The antenna can effectively transmit and receive signals, wherein the filtering part is designed to resonate in the TE101 mode by the first cavity 21 and the second cavity 22, and the third cavity 23 is symmetrically distributed and designed to resonate in the TE201 mode, and the resonant frequency is 27 GHz, wherein the TE201 mode has two field vectors with the same amplitude and opposite phases, and the power distribution four-way signal output and filtering response are achieved by coupling and mixing the two modes of SIW resonant cavities, which can also be called the filtering power division part. The design of the filtering antenna is based on the comprehensive design of the filter. The antenna is used as the last stage of the filter. The antenna is also part of the filter resonance while radiating. This integrated design reduces the addition of additional components and additional circuit assistance compared to the independent assembly of individual devices in the system, and has the advantages of high integration and compact structure.

[0041] The substrate integrated waveguide resonant cavity adopts SIW structure, which has the characteristics of low insertion loss, high integration, easy processing, high Q value, miniaturization, etc. It can effectively suppress interference signals and improve transmission quality. It is particularly outstanding in high-frequency applications and meets the needs of high-speed data transmission. Its high integration design reduces the space occupied by circuit boards. It adopts PCB circuit board design and is suitable for modern communication equipment, which improves the portability and functionality of the equipment. The patch array antenna adopts 2×2 radiating patch structure. The array of four units can improve the gain and directivity of the antenna. It is easy to process, small in size and low in cost. It is consistent with the trend of future systems towards miniaturization and high integration, and effectively addresses the problem of adding additional components and excessive volume when integrating a single device in current RF devices. The antenna operates in the n258 frequency band and meets the needs of modern 5G communications. For specific antenna performance, please refer to Figure 7-Figure 9 :like Figure 7 As shown, in the 26GHz-27.5GHz frequency band, S11 is less than -10dB. Figure 8 As shown in the figure, the actual maximum gain of the antenna is 12.5dB, with a relatively flat gain in the passband and a gain suppression of about -25dB outside the passband, which has a good out-of-band suppression effect. Figure 7 and Figure 8 It was observed that a high-order mode was generated at 32.6 GHz, but the electric field current at this point was found to be generated inside the first cavity and would not affect the overall performance of the antenna array, so no changes were made here. Fig. 9 is the radiation pattern of the antenna array at 27 GHz. The maximum actual gain is 12.5 dBi. The 3 dB beamwidths of the xoz and yoz planes are 32.8° and 31.5° respectively. The cross-polarization suppression in the main beam is greater than 28 dB and 48 dB respectively. It can be seen that the electrical performance of the antenna array is excellent and meets the design requirements.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compact millimeter wave high-gain filtering antenna array, characterized in that: The invention comprises, from top to bottom, a patch array antenna, an upper dielectric substrate (10), an intermediate metal surface (30), a lower dielectric substrate (20), and a lower metal surface (40); a substrate integrated waveguide resonant cavity is arranged in the lower dielectric substrate (20); the substrate integrated waveguide resonant cavity is formed by enclosing a plurality of periodically distributed metallized through holes (50); the substrate integrated waveguide resonant cavity comprises a first cavity (21), a second cavity (22), and a third cavity (23); the first cavity (21), the second cavity (22), and the third cavity (23) are symmetrical about the central axis of the lower dielectric substrate (20); coupling windows are provided between adjacent cavities; a rectangular slot coupling groove (31) symmetrical about the central axis of the lower dielectric substrate (20) is provided on the intermediate metal surface (30); the position of the rectangular slot coupling groove (31) corresponds to the position of the patch array antenna; and a coplanar waveguide transmission line is etched on the lower metal surface (40).

2. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The first cavity (21) and the second cavity (22) resonate in the TE101 mode, and the third cavity (23) resonates in the TE201 mode.

3. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The substrate integrated waveguide resonant cavity is a SIW cavity, the TE201 mode has two field components with the same amplitude and opposite phases, and the third cavity (23) resonating in the TE201 mode realizes four-way signal output by utilizing the inherent modal energy distribution characteristics of the SIW cavity.

4. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The patch array antenna is a 2×2 radiation patch structure, wherein four radiation patches (60) are symmetrically distributed above the third cavity (23), and the rectangular slot coupling groove (31) is located below the radiation patch (60).

5. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The rectangular gap coupling slot (31) achieves matching by means of electrical coupling.

6. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The coplanar waveguide transmission line is carved from the edge of the lower metal surface (40) and extends into the interior of the substrate integrated waveguide resonant cavity.

7. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: Two axisymmetric L-shaped slots (41) are etched in the area of ​​the lower metal surface (40) located within the metallized through hole (50) array, and the edges of the L-shaped slots (41) that contact the edge of the lower metal surface (40) are arranged parallel to the edge of the lower metal surface (40), and the lower metal surface area between the two axisymmetric L-shaped slots and the two L-shaped slots form a coplanar waveguide transmission line, and the substrate integrated waveguide resonant cavity is fed through the coplanar waveguide transmission line.

8. The compact millimeter wave high gain filtering antenna array according to claim 1, characterized in that: The material of the upper dielectric substrate (10) and the lower dielectric substrate (20) is Taconic TLY, and the relative dielectric constant is 2.2 and the loss tangent is 0.0009.

9. The compact millimeter wave high gain filtering antenna array according to claim 4, characterized in that: The shortest distance between the edge of the radiation patch (60) away from the coplanar waveguide transmission line and the edge of the rectangular slot coupling groove (31) at its corresponding position is 0.665 mm, and the shortest distance between the edge of the radiation patch (60) close to the coplanar waveguide transmission line and the edge of the rectangular slot coupling groove (31) at its corresponding position is 0.565 mm.

10. The compact millimeter wave high gain filtering antenna array according to claim 4, characterized in that: The radiation patch (60) is a square patch with a thickness of 0.035 mm and a side length of 3.2 mm. The edge spacing between two radiation patches (60) symmetrical about the central axis of the upper dielectric substrate (10) is 6.8 mm, and the edge spacing between two radiation patches (60) located on the same side of the central axis is 6.1 mm.

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