A phased array antenna with high left-right circular polarization consistency

Abstract

The present invention discloses a phased array antenna with high left-right circular polarization consistency, belonging to the field of antenna engineering technology, including a phased array antenna unit, the phased array antenna unit including a first dielectric layer, a second dielectric layer, a metal cavity, a metal floor, a metal isolation cavity and a back cavity metal floor stacked from top to bottom, a first circular patch and a second circular patch are arranged in the second dielectric layer, a first coupling slot and a second coupling slot are arranged on the metal floor, a third dielectric layer and a fourth dielectric layer are stacked from top to bottom in the metal isolation cavity, a first feeding microstrip and a second feeding microstrip are arranged on the lower surface of the third dielectric layer, and the back cavity metal floor is connected to the bottom wall of the metal isolation cavity. The present invention can effectively reduce electromagnetic coupling interference, improve active standing wave characteristics, and effectively reduce the axial ratio during wide-angle scanning, greatly enhancing the consistency of left-right circular polarization radiation performance of the array antenna.

Description

Technical Field

[0001] The invention relates to the technical field of antenna engineering, and in particular to a phased array antenna with high left-right circular polarization consistency. Background Art

[0002] With the rapid development of modern radar systems, the demand for various radar array antennas is increasing. Compared with traditional mechanical scanning antenna radars, phased array antenna radars can achieve beam control more quickly, and therefore have better beam scanning and beam tracking capabilities. At the same time, phased array antennas have attracted more and more attention due to their advantages of low profile, small installed load, and wide beam coverage. However, traditional phased array antennas have a narrow beam scanning range and narrow bandwidth, which greatly limits the development of phased array antenna radars in various application scenarios.

[0003] A Chinese patent document with publication number CN115621748A and publication date January 17, 2023 discloses a wide bandwidth and angle scanning circularly polarized millimeter wave phased array antenna unit, comprising:

[0004] A first dielectric layer, a second dielectric layer and a third dielectric layer are stacked in sequence;

[0005] A radiation patch, arranged on a side of the first dielectric layer away from the second dielectric layer, the radiation patch being a circular microstrip patch;

[0006] A first metal layer is sandwiched between the first dielectric layer and the second dielectric layer, two coupling slots and a plurality of isolation slots are provided on the first metal layer, the two coupling slots are arranged to be rotationally symmetrical about a rotation center, the rotation center coincides with the center of the radiation patch in the stacking direction, and one end of each coupling slot has a first arc slot bent toward one side, and the other end has a second arc slot bent toward the opposite other side, so as to excite two electromagnetic modes perpendicular to each other, and the plurality of isolation slots are arranged around the periphery of the two coupling slots;

[0007] A feeding microstrip, sandwiched between the second dielectric layer and the third dielectric layer, the feeding microstrip comprising a connecting portion and a feeding portion, the feeding portion being arranged corresponding to the two coupling slots, and being used for coupling and feeding the radiation patch through the two coupling slots;

[0008] The second metal layer is attached to a side of the third dielectric layer away from the second dielectric layer. The second metal layer is provided with a coaxial feeding point, and the coaxial feeding point is electrically connected to the connecting portion.

[0009] The wide bandwidth and angle scanning circularly polarized millimeter wave phased array antenna unit disclosed in the patent document effectively reduces the complexity of the system, saves space and wiring difficulty, and reduces the design difficulty and cost by adopting a circularly polarized antenna structure with single-point feeding. However, there is strong electromagnetic coupling interference, which affects the active standing wave characteristics, and the consistency of circularly polarized radiation performance is poor. Summary of the invention

[0010] In order to overcome the defects of the above-mentioned prior art, the present invention provides a phased array antenna with high left-right circular polarization consistency. The present invention can effectively reduce electromagnetic coupling interference, improve active standing wave characteristics, and effectively reduce the axial ratio during wide-angle scanning, thereby greatly enhancing the consistency of the left-right circular polarization radiation performance of the array antenna.

[0011] The present invention is achieved through the following technical solutions:

[0012] A phased array antenna with high left-right circular polarization consistency comprises a phased array antenna unit, wherein the phased array antenna unit comprises a first dielectric layer, a second dielectric layer, a metal cavity, a metal floor, a metal isolation cavity and a back cavity metal floor which are sequentially stacked from top to bottom, a first circular patch and a second circular patch are arranged in the second dielectric layer, the first circular patch is arranged in parallel above the second circular patch, a first coupling slot and a second coupling slot are arranged on the metal floor, a third dielectric layer and a fourth dielectric layer are sequentially stacked from top to bottom in the metal isolation cavity, a first feeding microstrip and a second feeding microstrip are arranged on the lower surface of the third dielectric layer, and the back cavity metal floor is connected to the bottom wall of the metal isolation cavity.

[0013] The lower end of the metal cavity is connected to the metal floor, and the upper end of the metal cavity extends into the second dielectric layer.

[0014] The first feeding microstrip includes a first feeding microstrip line, a second feeding microstrip line and a first feeding port, and the first feeding port is arranged on the second feeding microstrip line.

[0015] The first feeding port is vertically connected to the second feeding microstrip line, and the first feeding port extends upward into the third dielectric layer.

[0016] The second feeding microstrip includes a third feeding microstrip line, a fourth feeding microstrip line and a second feeding port, and the second feeding port is arranged on the fourth feeding microstrip line.

[0017] The second feeding port is vertically connected to the fourth feeding microstrip line, and the second feeding port extends upward into the third dielectric layer.

[0018] The radius of the second circular patch is greater than the radius of the first circular patch, and the vertical projections of the first circular patch and the second circular patch falling on the metal floor are concentric circles.

[0019] The length direction of the vertical projection of the first feeding microstrip on the metal floor is orthogonal to the length direction of the first coupling slot, and the length direction of the vertical projection of the second feeding microstrip on the metal floor is orthogonal to the length direction of the second coupling slot.

[0020] The metal isolation cavity is formed by a back cavity metal cavity body that is closed on all sides and an "X"-shaped metal isolation wall inside. The lower ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the back cavity metal floor, and the upper ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the metal floor.

[0021] The center of the vertical projection of the metal isolation wall in the metal isolation cavity onto the metal floor coincides with the center of the vertical projection of the first circular patch onto the metal floor.

[0022] The beneficial effects of the present invention are mainly manifested in the following aspects:

[0023] 1. Compared with the prior art, the present invention can effectively reduce electromagnetic coupling interference, improve active standing wave characteristics, and effectively reduce the axial ratio during wide-angle scanning, greatly enhancing the consistency of left-right circular polarization radiation performance of the array antenna.

[0024] 2. The present invention improves the impedance mismatch caused by the susceptance change caused by the scanning itself by loading the first dielectric layer above the second dielectric layer. The first dielectric layer is equivalent to a parallel capacitive susceptance. The scanning conductivity change rate slows down or intensifies with the change of the dielectric constant and thickness of the dielectric loading layer. By utilizing this characteristic of the dielectric loading layer, the susceptance change caused by the scanning itself can be offset, and the impedance fluctuation within the scanning range can be reduced, thereby achieving impedance matching during wide-angle scanning.

[0025] 3. In the present invention, the first dielectric layer not only improves the impedance matching of the antenna during large-angle scanning, but also reduces the left-right cross-polarization during large-angle scanning, and significantly reduces the axial ratio during large-angle scanning within the working frequency band.

[0026] 4. In view of the problems of high profile and narrow beam scanning range of existing circularly polarized phased array antennas, the present invention realizes coupled feeding excitation through the circular patch in the dielectric layer and the coupling gap on the metal floor through the feeding microstrip on the lower surface of the feeding dielectric layer, thereby broadening the impedance bandwidth.

[0027] 5. The present invention uses the cutoff effect of the metal cavity on the radiation field of the entire antenna unit to broaden the beam. The edge of the metal cavity will generate a parasitic electric field in the opposite direction to the aperture electric field when there is no cavity. The reverse magnetic current excited by the parasitic electric field will offset the electric field energy of the main radiation in the normal direction, and the radiated electric field in the low elevation angle direction will be superimposed in phase, thereby expanding the beam width of the antenna and increasing the beam scanning range of the antenna.

[0028] 6. The present invention enhances the anti-interference performance of the array and reduces the electromagnetic interference of the antenna array to other circuit systems by arranging a fourth dielectric layer and a back-cavity metal floor below the feed microstrip; the electromagnetic radiation of the array antenna in the normal reverse direction and the electromagnetic radiation from other components on the back of the array can be isolated by the back-cavity metal floor, thereby reducing the electromagnetic interference of other components to the array, and also reducing the electromagnetic interference of the array antenna in the normal reverse direction.

[0029] 7. In the present invention, the radius of the second circular patch is greater than the radius of the first circular patch, and the vertical projections of the first circular patch and the second circular patch on the metal floor are concentric circles, so that the antenna generates another adjacent high-frequency resonance point based on the original resonance, thereby effectively widening the impedance bandwidth of the antenna.

[0030] 8. In the present invention, the length direction of the vertical projection of the first feeding microstrip on the metal floor is orthogonal to the length direction of the first coupling slot, and the length direction of the vertical projection of the second feeding microstrip on the metal floor is orthogonal to the length direction of the second coupling slot. This enables the antenna to more easily excite left-hand circular polarization or right-hand circular polarization, and has good circular polarization characteristics within a wide-angle scanning range.

[0031] 9. In the present invention, the metal isolation cavity is formed by a back cavity metal cavity body that is closed on all sides outside and an "X"-shaped metal isolation wall that is connected to each other inside. The lower ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the back cavity metal floor, and the upper ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the metal floor. The back cavity metal cavity body that is closed on all sides outside can weaken the coupling between antenna units. The lower end of the "X"-shaped metal isolation wall inside is connected to the back cavity metal floor, and the upper end is connected to the metal floor, so that the feeding port and the feeding microstrip line in the unit are spatially isolated from each other, and the serious coupling between the two orthogonal feeding ports in the unit is weakened. The electromagnetic coupling interference between and within the units is significantly reduced, the active standing wave characteristics are improved, and the axial ratio during wide-angle scanning is effectively reduced. In addition, because physical isolation is achieved in space, the consistency of the left-right circularly polarized radiation performance of the antenna is greatly enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementations, wherein:

[0033] Figure 1 An exploded view of the phased array antenna unit of the present invention;

[0034] Figure 2 is a top view of the first feeding microstrip of the present invention;

[0035] Figure 3is a top view of the second feeding microstrip of the present invention;

[0036] Figure 4 It is a schematic diagram of the cross-sectional structure of an 8×8 array of the phased array antenna of the present invention;

[0037] Figure 5 This is a diagram of the active standing wave simulation results of the phased array antenna of the present invention;

[0038] Figure 6 It is a simulated radiation pattern of left-hand circularly polarized beam scanning of the phased array antenna of the present invention at an azimuth angle of 0° and an operating frequency of 27.5 GHz;

[0039] Figure 7 The simulated radiation pattern of the left-hand circularly polarized beam scanning of the phased array antenna of the present invention at an azimuth angle of 0° and an operating frequency of 31 GHz;

[0040] Figure 8 It is a simulated radiation pattern of right-hand circularly polarized beam scanning of the phased array antenna of the present invention at an azimuth angle of 90° and an operating frequency of 27.5 GHz;

[0041] Fig. 9 It is a right-hand circularly polarized beam scanning simulation pattern of the phased array antenna of the present invention in an azimuth plane with an azimuth angle of 90° and an operating frequency of 31 GHz;

[0042] Markings in the figure: 1, first dielectric layer, 2, second dielectric layer, 3, metal cavity, 41, first circular patch, 42, second circular patch, 5, metal floor, 6, first coupling gap, 7, second coupling gap, 8, third dielectric layer, 9, first feeding microstrip, 91, first feeding microstrip line, 92, second feeding microstrip line, 93, first feeding port, 10, second feeding microstrip, 101, third feeding microstrip line, 102, fourth feeding microstrip line, 103, second feeding port, 11, fourth dielectric layer, 12, metal isolation cavity, 13, back cavity metal floor. DETAILED DESCRIPTION

[0043] Example 1

[0044] See also Figure 1A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0045] This embodiment is the most basic implementation method. Compared with the prior art, it can effectively reduce electromagnetic coupling interference, improve active standing wave characteristics, and effectively reduce the axial ratio during wide-angle scanning, greatly enhancing the consistency of left-right circular polarization radiation performance of the array antenna.

[0046] Example 2

[0047] See also Figure 1 A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0048] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0049] This embodiment is a preferred implementation method, which improves the impedance mismatch caused by the susceptance change caused by the scanning itself by loading the first dielectric layer 1 above the second dielectric layer 2. The first dielectric layer 1 is equivalent to a parallel capacitive susceptance, and the scanning conductivity change rate slows down or intensifies with the change of the dielectric constant and thickness of the dielectric loading layer. By utilizing this characteristic of the dielectric loading layer, the susceptance change caused by the scanning itself can be offset, and the impedance fluctuation within the scanning range can be reduced, thereby achieving impedance matching during wide-angle scanning.

[0050] Example 3

[0051] See also Figure 1 and Figure 2 A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0052] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0053] Preferably, the first feeding microstrip 9 includes a first feeding microstrip line 91 , a second feeding microstrip line 92 and a first feeding port 93 , and the first feeding port 93 is arranged on the second feeding microstrip line 92 .

[0054] This embodiment is another preferred implementation mode. The first dielectric layer 1 not only improves the impedance matching of the antenna during large-angle scanning, but also reduces the left-right cross-polarization during large-angle scanning, and significantly reduces the axial ratio during large-angle scanning within the working frequency band.

[0055] Example 4

[0056] See also Figure 1-Figure 3 A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0057] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0058] The first feeding microstrip 9 includes a first feeding microstrip line 91 , a second feeding microstrip line 92 and a first feeding port 93 . The first feeding port 93 is arranged on the second feeding microstrip line 92 .

[0059] The first feeding port 93 is vertically connected to the second feeding microstrip line 92 , and the first feeding port 93 extends upward into the third dielectric layer 8 .

[0060] The second feeding microstrip 10 includes a third feeding microstrip line 101 , a fourth feeding microstrip line 102 and a second feeding port 103 . The second feeding port 103 is arranged on the fourth feeding microstrip line 102 .

[0061] The second feeding port 103 is vertically connected to the fourth feeding microstrip line 102 , and the second feeding port 103 extends upward into the third dielectric layer 8 .

[0062] This embodiment is another preferred implementation method. To address the problems of high profile and narrow beam scanning range of existing circularly polarized phased array antennas, the circular patch arranged in the dielectric layer and the coupling gap on the metal floor 5 complete the coupled feeding excitation through the feeding microstrip on the lower surface of the feeding dielectric layer, thereby broadening the impedance bandwidth.

[0063] Example 5

[0064] See also Figure 1-Figure 3 A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0065] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0066] The first feeding microstrip 9 includes a first feeding microstrip line 91 , a second feeding microstrip line 92 and a first feeding port 93 . The first feeding port 93 is arranged on the second feeding microstrip line 92 .

[0067] The first feeding port 93 is vertically connected to the second feeding microstrip line 92 , and the first feeding port 93 extends upward into the third dielectric layer 8 .

[0068] The second feeding microstrip 10 includes a third feeding microstrip line 101 , a fourth feeding microstrip line 102 and a second feeding port 103 . The second feeding port 103 is arranged on the fourth feeding microstrip line 102 .

[0069] The second feeding port 103 is vertically connected to the fourth feeding microstrip line 102 , and the second feeding port 103 extends upward into the third dielectric layer 8 .

[0070] The radius of the second circular patch 42 is greater than the radius of the first circular patch 41 , and the vertical projections of the first circular patch 41 and the second circular patch 42 falling on the metal floor 5 are concentric circles.

[0071] This embodiment is another preferred implementation method, in which the metal cavity 3 has a cutoff effect on the radiation field of the entire antenna unit to broaden the beam. The edge of the metal cavity 3 will generate a parasitic electric field in the opposite direction to the aperture electric field when there is no cavity. The reverse magnetic current excited by the parasitic electric field will offset the electric field energy of the main radiation in the normal direction, and the radiated electric field in the low elevation angle direction will be superimposed in phase, thereby expanding the beam width of the antenna and increasing the beam scanning range of the antenna.

[0072] By setting the fourth dielectric layer 11 and the back cavity metal floor 13 under the feeding microstrip, the anti-interference performance of the array is enhanced and the electromagnetic interference of the antenna array to other circuit systems is weakened; the electromagnetic radiation of the array antenna to the normal reverse direction and the electromagnetic radiation from other components on the back of the array can be isolated by the back cavity metal floor 13, thereby reducing the electromagnetic interference of other components to the array, and also weakening the electromagnetic interference of the array antenna to the normal reverse direction.

[0073] The radius of the second circular patch 42 is greater than that of the first circular patch 41, and the vertical projections of the first circular patch 41 and the second circular patch 42 on the metal floor 5 are concentric circles, so that the antenna generates another adjacent high-frequency resonance point based on the original resonance, thereby effectively widening the impedance bandwidth of the antenna.

[0074] Example 6

[0075] See also Figure 1-Figure 3A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0076] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0077] The first feeding microstrip 9 includes a first feeding microstrip line 91 , a second feeding microstrip line 92 and a first feeding port 93 . The first feeding port 93 is arranged on the second feeding microstrip line 92 .

[0078] The first feeding port 93 is vertically connected to the second feeding microstrip line 92 , and the first feeding port 93 extends upward into the third dielectric layer 8 .

[0079] The second feeding microstrip 10 includes a third feeding microstrip line 101 , a fourth feeding microstrip line 102 and a second feeding port 103 . The second feeding port 103 is arranged on the fourth feeding microstrip line 102 .

[0080] The second feeding port 103 is vertically connected to the fourth feeding microstrip line 102 , and the second feeding port 103 extends upward into the third dielectric layer 8 .

[0081] Further preferably, the radius of the second circular patch 42 is greater than the radius of the first circular patch 41 , and the vertical projections of the first circular patch 41 and the second circular patch 42 falling on the metal floor 5 are concentric circles.

[0082] The length direction of the vertical projection of the first feeding microstrip 9 on the metal floor 5 is orthogonal to the length direction of the first coupling slot 6 , and the length direction of the vertical projection of the second feeding microstrip 10 on the metal floor 5 is orthogonal to the length direction of the second coupling slot 7 .

[0083] This embodiment is another preferred implementation mode. The length direction of the vertical projection of the first feeding microstrip 9 on the metal floor 5 is orthogonal to the length direction of the first coupling slot 6, and the length direction of the vertical projection of the second feeding microstrip 10 on the metal floor 5 is orthogonal to the length direction of the second coupling slot 7. This enables the antenna to more easily excite left-hand circular polarization or right-hand circular polarization, and has good circular polarization characteristics within a wide-angle scanning range.

[0084] Example 7

[0085] See also Figure 1-Figure 4 A phased array antenna with high left-right circular polarization consistency includes a phased array antenna unit, the phased array antenna unit includes a first dielectric layer 1, a second dielectric layer 2, a metal cavity 3, a metal floor 5, a metal isolation cavity 12 and a back cavity metal floor 13 stacked in sequence from top to bottom, a first circular patch 41 and a second circular patch 42 are arranged in the second dielectric layer 2, the first circular patch 41 is arranged in parallel above the second circular patch 42, a first coupling slot 6 and a second coupling slot 7 are arranged on the metal floor 5, a third dielectric layer 8 and a fourth dielectric layer 11 are stacked in sequence from top to bottom in the metal isolation cavity 12, a first feeding microstrip 9 and a second feeding microstrip 10 are arranged on the lower surface of the third dielectric layer 8, and the back cavity metal floor 13 is connected to the bottom wall of the metal isolation cavity 12.

[0086] The lower end of the metal cavity 3 is connected to the metal floor 5 , and the upper end of the metal cavity 3 extends into the second dielectric layer 2 .

[0087] The first feeding microstrip 9 includes a first feeding microstrip line 91 , a second feeding microstrip line 92 and a first feeding port 93 . The first feeding port 93 is arranged on the second feeding microstrip line 92 .

[0088] The first feeding port 93 is vertically connected to the second feeding microstrip line 92 , and the first feeding port 93 extends upward into the third dielectric layer 8 .

[0089] The second feeding microstrip 10 includes a third feeding microstrip line 101 , a fourth feeding microstrip line 102 and a second feeding port 103 . The second feeding port 103 is arranged on the fourth feeding microstrip line 102 .

[0090] The second feeding port 103 is vertically connected to the fourth feeding microstrip line 102 , and the second feeding port 103 extends upward into the third dielectric layer 8 .

[0091] The radius of the second circular patch 42 is greater than the radius of the first circular patch 41 , and the vertical projections of the first circular patch 41 and the second circular patch 42 falling on the metal floor 5 are concentric circles.

[0092] The length direction of the vertical projection of the first feeding microstrip 9 on the metal floor 5 is orthogonal to the length direction of the first coupling slot 6 , and the length direction of the vertical projection of the second feeding microstrip 10 on the metal floor 5 is orthogonal to the length direction of the second coupling slot 7 .

[0093] The metal isolation cavity 12 is formed by a back cavity metal cavity body that is closed on all sides and an "X"-shaped metal isolation wall inside. The lower ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the back cavity metal floor 13, and the upper ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the metal floor 5.

[0094] The center of the vertical projection of the metal isolation wall in the metal isolation cavity 12 onto the metal floor 5 coincides with the center of the vertical projection of the first circular patch 41 onto the metal floor 5 .

[0095] This embodiment is the best implementation mode. The metal isolation cavity 12 is formed by a back cavity metal cavity body that is closed on all sides and an "X"-shaped metal isolation wall inside. The lower ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the back cavity metal floor 13, and the upper ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the metal floor 5. The back cavity metal cavity body that is closed on all sides can weaken the coupling between antenna units. The lower end of the "X"-shaped metal isolation wall inside is connected to the back cavity metal floor 13, and the upper end is connected to the metal floor 5, so that the feeding port and the feeding microstrip line in the unit are spatially isolated from each other, and the serious coupling between the two orthogonal feeding ports in the unit is weakened. The electromagnetic coupling interference between and within the units is significantly reduced, the active standing wave characteristics are improved, and the axial ratio during wide-angle scanning is effectively reduced. In addition, because physical isolation is achieved in space, the consistency of the left-right circularly polarized radiation performance of the antenna is greatly enhanced.

[0096] Next, simulation software is used to simulate and analyze the active standing wave of the phased array antenna and the achievable gain during large-angle scanning. The simulation results are as follows: Figures 5 to 9 shown.

[0097] from Figure 5 It can be seen that the units in the array exhibit good impedance matching characteristics for large-angle scanning. The simulation results show that the frequency band where the active standing wave of the port of the unit in the array is lower than 2.5 is 27.5 GHz-31 GHz, and the working bandwidth of the antenna reaches about 12%. Moreover, when the phased array is scanned at a large angle, the active standing wave of the port of the unit in the array is still lower than 2.5. The simulation results are in good agreement with the design requirements of the phased array, and the impedance matching characteristics of the phased array for large-angle scanning are well realized.

[0098] from Figures 6 to 9It can be seen that when the array antenna scans the left-hand circularly polarized beam at an angle of 0-60° in the working frequency band of 27.5 GHz-31 GHz, the difference between the achievable gain at different azimuth planes and angles relative to the achievable gain in the normal direction is within 5 dB, and it is also stable at more than 18.3 dBi during large-angle scanning.

[0099] In summary, according to the simulation results, the 8×8 array antenna can achieve good wide-angle circular polarization scanning characteristics in the frequency band of 27.5-31GHz, and the axial ratio is less than 3.2dB in the ±60° beam scanning range. The scanning gain of more than 18.3dBi is achieved in the ±60° left-hand circular polarization scanning range and the right-hand circular polarization scanning range. The difference between the gain and the normal gain within the ±60° range of the main beam scanning is within 5dB. Compared with the common phased array, the working bandwidth and axial ratio bandwidth of the phased array antenna of the present invention have achieved a large expansion, the gain during wide-angle scanning has been stably enhanced, the wide-angle matching scanning angle has been greatly improved, and good gain flatness and circular polarization characteristics have been achieved during the scanning process.

Claims

1. A phased array antenna with high consistency of left-right circular polarization, comprising a phased array antenna unit, characterized in that: The phased array antenna unit comprises a first dielectric layer (1), a second dielectric layer (2), a metal cavity (3), a metal floor (5), a metal isolation cavity (12) and a back cavity metal floor (13) which are stacked in sequence from top to bottom; a first circular patch (41) and a second circular patch (42) are arranged in the second dielectric layer (2); the first circular patch (41) is arranged in parallel above the second circular patch (42); a first coupling slot (6) and a second coupling slot (7) are arranged on the metal floor (5); a third dielectric layer (8) and a fourth dielectric layer (11) are stacked in sequence from top to bottom in the metal isolation cavity (12); a first feeding microstrip (9) and a second feeding microstrip (10) are arranged on the lower surface of the third dielectric layer (8); and the back cavity metal floor (13) is connected to the bottom wall of the metal isolation cavity (12); The metal isolation cavity (12) is formed by connecting a back cavity metal cavity body that is closed on all sides and an "X"-shaped metal isolation wall inside; the lower ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the back cavity metal floor (13); and the upper ends of the back cavity metal cavity body and the metal isolation wall are respectively connected to the metal floor (5).

2. The phased array antenna with high consistency of left-right circular polarization according to claim 1, characterized in that: The lower end of the metal cavity (3) is connected to the metal floor (5), and the upper end of the metal cavity (3) extends into the second dielectric layer (2).

3. The phased array antenna with high consistency of left-right circular polarization according to claim 1, characterized in that: The first feeding microstrip (9) comprises a first feeding microstrip line (91), a second feeding microstrip line (92) and a first feeding port (93); the first feeding port (93) is arranged on the second feeding microstrip line (92).

4. The phased array antenna with high consistency of left-right circular polarization according to claim 3, characterized in that: The first feeding port (93) is vertically connected to the second feeding microstrip line (92), and the first feeding port (93) extends upward into the third dielectric layer (8).

5. The phased array antenna with high left-right circular polarization consistency according to claim 1, characterized in that: The second feeding microstrip (10) comprises a third feeding microstrip line (101), a fourth feeding microstrip line (102) and a second feeding port (103); the second feeding port (103) is arranged on the fourth feeding microstrip line (102).

6. The phased array antenna with high consistency of left-right circular polarization according to claim 5, characterized in that: The second feeding port (103) is vertically connected to the fourth feeding microstrip line (102), and the second feeding port (103) extends upward into the third dielectric layer (8).

7. The phased array antenna with high consistency of left-right circular polarization according to claim 1, characterized in that: The radius of the second circular patch (42) is greater than the radius of the first circular patch (41), and the vertical projections of the first circular patch (41) and the second circular patch (42) falling on the metal floor (5) are concentric circles.

8. The phased array antenna with high consistency of left-right circular polarization according to claim 1, characterized in that: The length direction of a vertical projection of the first feeding microstrip (9) falling on the metal floor (5) is orthogonal to the length direction of the first coupling slot (6), and the length direction of a vertical projection of the second feeding microstrip (10) falling on the metal floor (5) is orthogonal to the length direction of the second coupling slot (7).

9. The phased array antenna with high consistency of left-right circular polarization according to claim 1, characterized in that: The center of a vertical projection of the metal isolation wall in the metal isolation cavity (12) onto the metal floor (5) coincides with the center of a vertical projection of the first circular patch (41) onto the metal floor (5).

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