Compact millimeter wave dual-polarization filtering antenna and array

Abstract

The invention discloses a compact millimeter wave dual-polarization filtering antenna and array, which comprises 11 layers of structures (a first metal layer to a sixth metal layer, three dielectric layers and two bonding layers) and three types of metalized via holes which are sequentially stacked from top to bottom, the feed through hole penetrates through the first dielectric layer to the third dielectric layer, the short-circuit through hole penetrates through the first dielectric layer to the third dielectric layer, and the shielding hole penetrates through the third dielectric layer. Wherein a cross-shaped radiation patch and a C-shaped parasitic metal strip line are arranged on the first metal layer; an annular driving patch is arranged on the second metal layer; the third metal layer is provided with a feed metal strip line and a parasitic metal strip line. The fourth metal layer is provided with a parasitic open-circuit branch. A first grounding plane is arranged on the fifth metal layer; the sixth metal layer is provided with a second grounding plane and an anti-pad. The working frequency band covers the n258 frequency band and the n257 frequency band of 5G millimeter waves, dual-polarization radiation and effective out-of-band rejection can be achieved, and meanwhile the antenna has the advantages of being compact in structure and light and handy in appearance.

Description

Technical Field

[0001] The present invention belongs to the field of electronics, and in particular relates to a compact millimeter wave dual-polarization filtering antenna and array. Background Art

[0002] In recent years, the fifth generation of mobile communication technology has become increasingly mature, and the sixth generation of mobile communication technology is about to arrive, which has brought significant opportunities and challenges to the development of the Internet of Things. Millimeter wave communication technology, as an important component of it, has also received great attention. Therefore, more and more mobile terminal devices such as mobile phones, tablets, laptops, drones and wearable devices have begun to support millimeter wave communication, aiming to achieve high-speed, low-latency Internet of Things communication.

[0003] In order to ensure that mobile terminal devices are lightweight and convenient, requirements such as miniaturization and high integration are put forward for RF devices and systems. Antennas and filters are important components in RF systems. Integrating the two together to design a filtering antenna can effectively reduce the system size.

[0004] In order to overcome the high path loss in the millimeter wave frequency band and improve the system's channel capacity and spectrum efficiency, an active phased array module consisting of dual-polarized antennas is generally used to achieve multi-beam and beamforming.

[0005] Experts, scholars, and engineers in related fields have conducted extensive research on millimeter-wave filter antennas and achieved a series of technical achievements. However, with regard to the publicly available millimeter-wave filter antenna technology and structure, the following problems still exist:

[0006] 1. The antenna size is generally large and not compact enough. Most antennas are only single antenna units and are not suitable for forming phased arrays.

[0007] 2. Antennas are mostly single-polarized, and it is difficult to expand them to dual-polarization, making them unsuitable for phased array modules for mobile terminals.

[0008] 3. The integration of antennas and active circuits is difficult. Millimeter-wave filter antennas designed by relevant scholars use structures such as microstrip lines or substrate-integrated waveguides, or adopt differential feed architectures. This limits the use of antennas with active circuits to form phased array systems. Summary of the Invention

[0009] The purpose of the present invention is to provide a compact millimeter-wave dual-polarization filtering antenna and array, whose operating frequency band covers the 5G millimeter-wave n258 band (24.25-27.5GHz) and n257 band (26.5-29.5GHz), can produce effective out-of-band suppression, and has the characteristics of high frequency selectivity and high polarization isolation. At the same time, it can be expanded into an antenna array and combined with active circuits to form a phased array to achieve ideal beam scanning.

[0010] In order to achieve the above object, the solution of the present invention is:

[0011] A compact millimeter-wave dual-polarization filter antenna according to the present invention comprises, stacked sequentially from top to bottom, a first metal layer, a first dielectric layer, a second metal layer, a first adhesive layer, a third metal layer, a second dielectric layer, a fourth metal layer, a second adhesive layer, a fifth metal layer, a third dielectric layer, and a sixth metal layer, as well as three types of metalized vias: a feed via extending from the first dielectric layer to the third dielectric layer, a short-circuit via extending from the first dielectric layer to the third dielectric layer, and a shielding via extending through the third dielectric layer. The first metal layer comprises a cross-shaped radiating patch and a C-shaped parasitic metal stripline; the second metal layer comprises a ring-shaped driving patch; the third metal layer comprises a feed metal stripline and a parasitic metal stripline; the fourth metal layer comprises a parasitic open-circuit stub; the fifth metal layer comprises a first ground plane; and the sixth metal layer comprises a second ground plane and an anti-pad. The feeding metal strip line, feeding via and anti-pad form an L-shaped feeding probe, the parasitic metal strip line and the short-circuit via form a parasitic short-circuit branch connected to the first ground plane and the second ground plane, and the antenna is fed through the L-shaped feeding probe.

[0012] Furthermore, the cross-shaped radiation patch is placed in a manner of rotating 45° around the center, the four branches of the cross-shaped radiation patch are loaded with C-shaped parasitic metal strips, and the cross-shaped radiation patch coincides with the center of the annular driving patch below.

[0013] Furthermore, the antenna includes two orthogonally placed L-shaped feeding probes of the same size, wherein the left L-shaped feeding probe connection port 1 excites V-polarized radiation, and the right L-shaped feeding probe connection port 2 excites H-polarized radiation, and there is no overlap between the L-shaped feeding probe and the cross-shaped radiating patch, and between the L-shaped feeding probe and the annular driving patch.

[0014] Furthermore, two parasitic short-circuit branches are symmetrically loaded on both sides of the L-shaped feeding probe, and the parasitic short-circuit branches are connected to the first ground plane and the second ground plane.

[0015] Furthermore, the L-shaped feeding probe is loaded with a parasitic open-circuit stub.

[0016] Furthermore, two feeding holes are etched on the first ground plane to allow the feeding through-hole to pass through.

[0017] Furthermore, the shielding holes are arranged in a circle around the anti-pad, forming a quasi-coaxial structure with the feeding through hole to prevent energy leakage.

[0018] The millimeter wave dual-polarization filter antenna array formed by the compact millimeter wave dual-polarization filter antenna of the present invention has a scale of 1×4, the first unit and the fourth unit as well as the second unit and the third unit are rotationally symmetric 180° about the array center, and the millimeter wave dual-polarization filter antenna array can achieve ±45° dual polarization.

[0019] Furthermore, the second and third units of the compact millimeter-wave dual-polarization filter antenna array are both equipped with a first-type decoupling structure to improve the polarization isolation between the second and third units. A second-type decoupling structure is installed in the center of the antenna array to improve the polarization isolation between the second and third units. The first-type decoupling structure is a U-shaped metal strip line, located on the third metal layer, with both ends pointing to the L-shaped feed probe. The second-type decoupling structure includes a Y-shaped metal patch and a short-circuit metal via on the first metal layer.

[0020] Furthermore, the antenna array is integrated with active circuits in the following two ways: 1) each unit is connected to an independent amplitude and phase controlled RF channel to achieve beam scanning; 2) all antenna units are connected to a single RF channel through a 1-to-4 power splitter to form a fixed beam in the normal direction.

[0021] Beneficial effects: The present invention provides a compact millimeter-wave dual-polarization filtering antenna, which has the following advantages: (1) the miniaturization and compactness of the antenna are achieved by the stacked coupling design of the cross-shaped radiating patch rotation layout and the annular driving patch; (2) broadband and effective out-of-band suppression are achieved by loading three types of structures, namely, C-shaped parasitic strip lines, parasitic short-circuit branches and bent open-circuit branches; (3) the unit structure can be seamlessly expanded to a ±45° dual-polarization array (such as a 1×4 example); combined with the decoupling structure (U-shaped metal strip lines, Y-shaped metal patches + metal through-holes), an isolation better than 19 dB can be achieved, and the out-of-band gain suppression level of the antenna array exceeds 16 dB within the ±45° beam scanning range; (4) the antenna is implemented using a multi-layer printed circuit board process, has a lightweight appearance, and is easy to integrate with active circuits to construct a phased array system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the exploded structure of a compact millimeter-wave dual-polarization filter antenna in a specific embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the stacked structure of the antenna in a specific embodiment of the present invention;

[0024] Figure 3This is a schematic diagram of the structure of the first metal layer of the antenna in a specific embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the second metal layer structure of the antenna in a specific embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the third metal layer of the antenna in a specific embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the structure of the fourth metal layer of the antenna in a specific embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of the fifth metal layer of the antenna in a specific embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the structure of the sixth metal layer of the antenna in a specific embodiment of the present invention;

[0030] Figure 9 This is a schematic structural diagram of a millimeter-wave dual-polarization filtering antenna array in a specific embodiment of the present invention;

[0031] Figure 10 Schematic diagram of the first type of decoupling structure in the antenna array in a specific embodiment of the present invention;

[0032] Figure 11 Schematic diagram of the second type of decoupling structure in the antenna array in a specific embodiment of the present invention;

[0033] Figure 12 The simulation and measured results of the S parameters of the compact millimeter-wave dual-polarization filter antenna in a specific embodiment of the present invention are as follows;

[0034] Figure 13 The simulation and measured results of the normalized gain pattern of the compact millimeter-wave dual-polarization filter antenna at 27 GHz in a specific embodiment of the present invention are as follows;

[0035] Figure 14 The simulation and measured results of the gain curve of the compact millimeter-wave dual-polarization filter antenna in a specific embodiment of the present invention are shown;

[0036] Figure 15 The simulation and measured results of the reflection coefficients of the first unit and the second unit of the millimeter wave dual-polarization filter antenna array in a specific embodiment of the present invention are as follows;

[0037] Figure 16 The simulation and measured results of the coupling between the first unit and the second unit, and between the second unit and the third unit, of the millimeter-wave dual-polarization filter antenna array in a specific embodiment of the present invention are as follows;

[0038] Figure 17 The present invention provides simulation and measured results of the polarization isolation of the first unit, the polarization isolation of the second unit, the polarization isolation between the first unit and the second unit, and the polarization isolation between the second unit and the third unit of the millimeter-wave dual-polarization filter antenna array in a specific embodiment of the present invention.

[0039] Figure 18 The simulation and measured results of the 45° polarization beam scanning pattern of the millimeter-wave dual-polarization filter antenna array at 27 GHz in a specific embodiment of the present invention are as follows;

[0040] Figure 19 The simulation and measured results of the -45° polarization beam scanning pattern of the millimeter-wave dual-polarization filter antenna array at 27 GHz in a specific embodiment of the present invention are as follows;

[0041] Figure 20 The simulation and measured results of the gain curves of the millimeter-wave dual-polarization filter antenna array in a specific embodiment of the present invention when the beam scanning angles are 0°, 15°, 30°, and 45°;

[0042] The figure shows: a compact millimeter-wave dual-polarization filtering antenna of the present invention includes a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a first adhesive layer 4, a third metal layer 5, a second dielectric layer 6, a fourth metal layer 7, a second adhesive layer 8, a fifth metal layer 9, a third dielectric layer 10, a sixth metal layer 11, a cross-shaped radiation patch 15, a C-shaped parasitic metal strip line 16, a ring-shaped driving patch 17, an L-shaped feeding probe 12 (including a feeding through hole 12-1, a feeding metal strip line 12-2 and an anti-pad 12-3), a parasitic short-circuit branch (including a short-circuit through hole 13-1 and a parasitic metal strip line 13-2), a parasitic open-circuit branch 18, a first ground plane 19, a feeding hole 21, a shielding hole 14, a second ground plane 20, a first type of decoupling structure 22, and a second type of decoupling structure 23. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below in conjunction with specific implementation methods and drawings.

[0044] This embodiment discloses a compact millimeter wave dual-polarization filtering antenna, such as Figure 1 and 2As shown, it includes, from top to bottom, a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a first adhesive layer 4, a third metal layer 5, a second dielectric layer 6, a fourth metal layer 7, a second adhesive layer 8, a fifth metal layer 9, a third dielectric layer 10 and a sixth metal layer 11, as well as three types of metallized vias, namely, a feed via 12-1 passing through the first dielectric layer to the third dielectric layer, a short-circuit via 13-1 passing through the first dielectric layer 2 to the third dielectric layer 10, and a shielding hole 14 passing through the third dielectric layer.

[0045] like Figure 3 As shown, the first metal layer is provided with a cross-shaped radiation patch 15 and a C-shaped parasitic metal strip line 16. Figure 4 As shown, the second metal layer is provided with an annular driving patch 17. The cross-shaped radiation patch 15 is rotated 45 degrees about the center, and the center coincides with the annular radiation patch 17.

[0046] like Figure 5 As shown, the third metal layer is provided with a feeding metal strip line 12-2 and a parasitic metal strip line 13-2. The feeding metal strip line 12-2 is connected to the feeding via 12-1, and the parasitic metal strip line 13-2 is connected to the short-circuit via 13-1. The short-circuit via 13-1 and the parasitic metal strip line 13-2 form a parasitic short-circuit branch 13.

[0047] like Figure 6 As shown, the fourth metal layer is provided with a parasitic open stub 18. To reduce the occupied space, the parasitic open stub 18 is bent multiple times.

[0048] like Figure 7 As shown, the fifth metal layer is provided with a first ground plane 19. A feeding hole 21 is opened on the first ground plane to prevent short circuit through the feeding through hole 12-1.

[0049] like Figure 8 As shown, the sixth metal layer is provided with a second ground plane 20 and an anti-pad 12-3. The first ground plane 19 and the second ground plane 20 are connected through a shielding hole 14. The feed via 12-1, the feed metal strip line 12-2, and the anti-pad 12-3 form an L-shaped feed probe 12. The antenna includes vertically arranged L-shaped feed probes 12 of the same size to achieve dual-polarization radiation.

[0050] The working principle of the present invention is as follows: energy is coupled to the annular driving patch 17 through the L-shaped feeding probe 12, and then the annular driving patch 17 couples the energy to the cross-shaped radiation patch 15, and the cross-shaped radiation patch 15 radiates the energy into free space. The coupling between the L-shaped feeding probe 12 and the cross-shaped radiation patch 15, the coupling between the driving annular patch 17 and the cross-shaped radiation patch 15, and the coupling between the C-shaped parasitic metal strip line 16 and the cross-shaped radiation patch 15 are mixed electric coupling and magnetic coupling, which can introduce multiple radiation zero points at high frequencies to achieve out-of-band suppression of the antenna at high frequencies. The parasitic short-circuit branch 13 is equivalent to a band-stop filter, which can introduce radiation zero points at low frequencies to achieve out-of-band suppression of the antenna at low frequencies. The parasitic open-circuit branch 18 improves the overall out-of-band suppression of the antenna.

[0051] Another embodiment of the present invention is a millimeter wave dual-polarization filtering antenna array, such as Figure 9 As shown, the antenna array can achieve ±45° dual polarization, the structure scale is 1×4, and the first unit and the fourth unit, as well as the second unit and the third unit are rotationally symmetric 180° about the array center.

[0052] like Figure 10 As shown, the third metal layer of the second and third elements of the compact millimeter-wave dual-polarized antenna array is loaded with a first-type decoupling structure 22. This first-type decoupling structure 22 is a U-shaped metal strip with its ends pointing toward the two L-shaped feed probes of the antenna. This first-type decoupling structure 22 introduces an additional coupling path between the two ports of the second and third elements, canceling out the energy of the original coupling path and improving the polarization isolation between the second and third elements.

[0053] like Figure 11 As shown, the center of the compact millimeter-wave dual-polarized antenna array is loaded with a second-type decoupling structure 23. This structure consists of a Y-shaped metal patch 23-1 and a short-circuit metal via 23-2 located on the first metal layer. The second-type decoupling structure 23 is symmetrically loaded at the center of the array. This structure introduces an additional coupling path between the polarization ports of the second and third elements, canceling out the energy in the original coupling path and improving the polarization isolation between the second and third elements.

[0054] To verify the feasibility of a compact millimeter-wave dual-polarized antenna proposed in the present invention, the compact millimeter-wave dual-polarized antenna was first simulated using a commercial full-wave simulation software, and then fabricated according to the technical solution provided by the present invention. As a specific example, the first dielectric layer of the compact millimeter-wave dual-polarized antenna uses a Rogers RO4003C substrate with a thickness of 0.5 mm, the first adhesive layer uses a Rogers RO4450F prepreg with a thickness of 0.2 mm, the second dielectric layer uses a Rogers RT / duroid 6006 substrate with a thickness of 0.254 mm, the second adhesive layer uses a Rogers RO4450F prepreg with a thickness of 0.1 mm, and the third dielectric layer uses a Rogers RO4003C substrate with a thickness of 0.3 mm. Figures 12 to 14 The simulation and measurement results of the exemplary antenna are given: the |S 11 | and |S 22 | < -10 dB bandwidth covers the 5G millimeter-wave n258 band (24.25 - 27.5 GHz) and n257 band (26.5 - 29.5 GHz)), the polarization isolation is higher than 23 dB, the maximum gain is 6 dBi, the out-of-band rejection is better than 20 dB, and it has high frequency selectivity.

[0055] Furthermore, according to the technical solution provided by the present invention, a 1×4 millimeter-wave dual-polarized filter antenna array was simulated and fabricated. Figures 15 to 20 The relevant simulation and measurement results are given respectively. The overlapping bandwidth of the reflection coefficient of the unit in the antenna array < -10 dB covers the 5G millimeter-wave n258 band (24.25 - 27.5 GHz) and n257 band (26.5 - 29.5 GHz), the co-polarization port isolation of the array is better than 19 dB, and the cross-polarization port isolation is better than 20 dB. The 3 dB beam scanning range of the millimeter-wave dual-polarized filter antenna array is from -47° to 43°, and the 5 dB beam scanning range is from -62° to 56°, with good scanning performance. When the beam direction of the millimeter-wave dual-polarized filter antenna array is normal, the out-of-band gain suppression level is better than 20 dB, and when the beam scanning angle is less than 45°, the out-of-band gain suppression level is better than 16 dB.

[0056] The above are only the preferred embodiments of the present invention, which are used to illustrate the technical idea of the present invention. The protection scope of the present invention cannot be limited by this. Without departing from the principle of the present invention, any modification made falls within the protection scope of the present invention.

Claims

1. A compact millimeter wave dual-polarization filtering antenna, characterized in that The invention comprises a first metal layer (1), a first dielectric layer (2), a second metal layer (3), a first adhesive layer (4), a third metal layer (5), a second dielectric layer (6), a fourth metal layer (7), a second adhesive layer (8), a fifth metal layer (9), a third dielectric layer (10) and a sixth metal layer (11) stacked in sequence from top to bottom, and three types of metallized vias, namely, a feed via (12-1) passing through the first dielectric layer (2) to the third dielectric layer (10), a short-circuit via (13-1) passing through the first dielectric layer (2) to the third dielectric layer (10) and a shielding hole (14) passing through the third dielectric layer (10); wherein the first metal layer (1) is provided with a cross-shaped radiation patch (15) and a C-shaped parasitic metal strip line (16); the second metal layer (3) is provided with a The invention discloses a ring-shaped driving patch (17); a feeding metal strip line (12-2) is provided on the third metal layer (5) to connect the feeding through hole (12-1) and a parasitic metal strip line (13-2) is provided to connect the short-circuit through hole (13-1); a parasitic open-circuit branch (18) is provided on the fourth metal layer (7); a first ground plane (19) is provided on the fifth metal layer (9); a second ground plane (20) and an anti-welding pad (12-3) are provided on the sixth metal layer (11); the feeding through hole (12-1), the feeding metal strip line (12-2) and the anti-welding pad (12-3) form an L-shaped feeding probe (12); the short-circuit through hole (13-1) and the parasitic metal strip line (13-2) form a parasitic short-circuit branch (13); and the excitation of the antenna is fed through the L-shaped feeding probe (12).

2. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: The cross-shaped radiation patch (15) is placed in a manner of being rotated 45 degrees around the center, and the four branches of the cross-shaped radiation patch (15) are loaded with C-shaped parasitic metal strip lines (16). The cross-shaped radiation patch (15) coincides with the center of the annular driving patch (17) below.

3. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: The antenna comprises two L-shaped feeding probes (12) which are orthogonally placed and have exactly the same size, wherein the left L-shaped feeding probe connection port 1 excites V-polarized radiation, and the right L-shaped feeding probe connection port 2 excites H-polarized radiation, and there is no overlap between the L-shaped feeding probe (12) and the cross-shaped radiating patch (15) and between the L-shaped feeding probe (12) and the annular driving patch (17).

4. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: Two parasitic short-circuit branches (13) are symmetrically loaded on both sides of each L-shaped feeding probe (12), and the parasitic short-circuit branches (13) are connected to a first ground plane (19) and a second ground plane (20).

5. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: Each feeding L-shaped feeding probe (12) is loaded with a parasitic open-circuit stub (18).

6. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: Two feeding holes (21) are etched on the first ground plane to prevent short circuit through the feeding through hole (12-1).

7. The compact millimeter-wave dual-polarization filtering antenna according to claim 1, characterized in that: The shielding holes (14) are arranged in a circle around the anti-welding pad (12-3), and form a quasi-coaxial structure with the feeding through hole (12-1) to prevent energy leakage.

8. A millimeter-wave dual-polarization filtering antenna array, characterized in that: A 1×4 array is formed by any one of the antenna units of claims 1-7; the first unit and the fourth unit as well as the second unit and the third unit are rotationally symmetric by 180° about the center of the array.

9. The millimeter wave dual-polarization filtering antenna array according to claim 8, characterized in that: The second unit and the third unit of the antenna array are both loaded with a first type of decoupling structure (22) for improving the polarization isolation of the second unit and the third unit; the center of the antenna array is loaded with a second type of decoupling structure (23) for improving the polarization isolation between the second unit and the third unit; The first type of decoupling structure (22) is a U-shaped metal strip line, which is provided on the third metal layer (5) and has two ends pointing to the L-shaped feeding probe (12); The second type of decoupling structure (23) comprises a Y-shaped metal patch (23-1) and a short-circuit metal through hole (23-2) of the first metal layer (1).

10. The millimeter wave dual-polarization filtering antenna array according to claim 8, characterized in that: The antenna array is integrated with active circuits in the following two ways: 1) each unit is connected to an independent amplitude and phase controlled RF channel to achieve beam scanning; 2) all antenna units are connected to a single RF channel through a 1-to-4 power splitter to form a fixed beam in the normal direction.

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