Phased-array antenna for solving axial ratio deterioration during large-angle scanning

Abstract

The invention belongs to the field of wireless communication, and relates to a phased-array antenna for solving axial ratio deterioration during large-angle scanning, which comprises a plurality of antenna units, the upper surface of each antenna unit is provided with a patch, the upper surface of each antenna unit is also provided with a resonant ring, and the resonant rings are arranged at the peripheries of the patches; a plurality of notches are formed in the edge of the patch, and the positions of the notches are in central symmetry; the resonant ring is provided with a plurality of openings, and the positions of the plurality of openings are in central symmetry. The openings of the resonant rings are in one-to-one correspondence with the notches of the patches, and the openings of the resonant rings and the corresponding notches are located on the same straight line penetrating through the circle center of the patches; the resonant ring is loaded around the patch, reverse current can be formed to counteract currents of X-axis and Y-axis components of the patch, the X-axis component current is projected to Rethyeta more than the Y-axis component current which is correspondingly counteracted by Rephi when scanning a large angle, the difference of dual-polarization components is reduced, and therefore large-angle axial ratio deterioration is restrained.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of wireless communication and relates to a phased array antenna for solving the axial ratio deterioration in large-angle scanning. BACKGROUND

[0002] The high flux and wide coverage requirements of a satellite communication system promote phased array antennas to become core components of low-orbit satellites and mobile terminals, but the axial ratio (AR) deteriorates sharply in large-angle beam scanning (such as more than ±60°), which leads to the dispersion of circular polarization energy, the sharp increase of polarization mismatch loss, and the significant reduction of transmission efficiency and anti-interference ability, and the problem is particularly prominent in the millimeter wave frequency band.

[0003] In the prior art, the research on axial ratio optimization mainly focuses on the unit structure design or polarization matching of fixed beam direction, such as improving the circular polarization performance through special patch shape, feed network symmetry design or dielectric substrate optimization. Although the axial ratio performance can be maintained in a small angle, the unit pattern distortion, mutual coupling effect and spatial phase delay caused by large-angle scanning (more than ±60°) lead to the deflection of the polarization main axis and the mismatch of the elliptical parameter.

[0004] Current solutions often require complex auxiliary structures or dynamic tuning circuits, which have problems such as high design complexity, limited bandwidth, and difficulty in adapting to multiple frequency bands and multiple scenarios. In view of this challenge, it is urgent to develop a phased array antenna that can adaptively compensate for polarization mismatch caused by large-angle scanning to meet the urgent needs of 5G / 6G communication systems for high-performance phased array antennas. SUMMARY

[0005] To solve the above-mentioned problems in the prior art, the application adopts a phased array antenna for solving the axial ratio deterioration in large-angle scanning, which comprises a plurality of antenna units, and each antenna unit is provided with a patch 7 on the upper surface, and each antenna unit is further provided with a resonant ring 8 on the upper surface, and the resonant ring 8 is arranged around the periphery of the patch 7.

[0006] The edge of the patch 7 is provided with a plurality of notches, and the positions of the plurality of notches are centrally symmetric.

[0007] The resonant ring 8 is provided with a plurality of openings, and the positions of the plurality of openings are centrally symmetric.

[0008] The openings of the resonant ring 8 correspond one-to-one to the notches of the patch 7, and the openings of the resonant ring 8 and the notches corresponding thereto are located on the same straight line passing through the center of the patch 7.

[0009] The antenna unit comprises a first dielectric substrate 1, and the patch 7 and the resonant ring 8 are arranged on the upper surface of the first dielectric substrate 1.

[0010] The first dielectric substrate 1 is provided below with a second dielectric substrate 2, and the second dielectric substrate 2 is an air dielectric substrate.

[0011] The second dielectric substrate 2 is provided below with a third dielectric substrate 3, and the third dielectric substrate 3 is provided with a main radiation patch 9.

[0012] The third dielectric substrate 3 is provided below with a fourth dielectric substrate 4, and the fourth dielectric substrate 4 is an air dielectric substrate.

[0013] The fourth dielectric substrate 4 is provided below with a fifth dielectric substrate 5, and the fifth dielectric substrate 5 is provided with a square-shaped gap.

[0014] The fifth dielectric substrate 5 is provided below with a sixth dielectric substrate 6, and the sixth dielectric substrate 6 is provided with a feed microstrip line 10.

[0015] Beneficial effects:

[0016] The application can form reverse current to offset the X and Y axis components of the patch by loading a resonant ring around the patch, and the X axis component current is projected on Retheta more than the Y axis corresponding to Rephi when scanning to a large angle, thereby reducing the difference between the two polarization components, and thus suppressing the deterioration of the large angle axial ratio. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A phased array antenna schematic diagram for solving the axial ratio deterioration in the large angle scanning provided by the embodiment of the application;

[0018] Figure 2 A schematic diagram of an antenna unit of a phased array antenna for solving the axial ratio deterioration in the large angle scanning provided by the embodiment of the application;

[0019] Figure 3 A schematic diagram of the Rephi, Retheta, Rex and Rey components of the antenna provided by the embodiment of the application with a resonant ring;

[0020] Figure 4 A schematic diagram of the Rephi, Retheta, Rex and Rey components of the antenna provided by the embodiment of the application without a resonant ring;

[0021] Figure 5 A current distribution schematic diagram provided by the embodiment of the application without a resonant ring;

[0022] Figure 6 A current distribution schematic diagram provided by the embodiment of the application with a resonant ring;

[0023] Figure 7 An axial ratio schematic diagram provided by the embodiment of the application without a resonant ring;

[0024] Figure 8 An axial ratio schematic diagram provided by the embodiment of the application with a resonant ring;

[0025] Wherein, 1 is the first dielectric substrate, 2 is the second dielectric substrate, 3 is the third dielectric substrate, 4 is the fourth dielectric substrate, 5 is the fifth dielectric substrate, 6 is the sixth dielectric substrate, 7 is a patch, 8 is a resonant ring, 9 is the main radiating patch, and 10 is the feed microstrip line. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] like Figure 1 , Figure 2 As shown, the embodiment of the present invention employs a phased array antenna that solves the problem of axial ratio degradation during large-angle scanning, including multiple antenna elements. Each antenna element has a patch 7 and a resonant ring 8 on its upper surface, with the resonant ring 8 surrounding the patch 7.

[0028] Each antenna unit includes, from top to bottom, a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a fourth dielectric substrate 4, a fifth dielectric substrate 5, and a sixth dielectric substrate 6; the second dielectric substrate 2 and the fourth dielectric substrate 4 are air dielectric substrates, and the patch 7 and the resonant ring 8 are disposed on the upper surface of the first dielectric substrate 1.

[0029] The third dielectric substrate 3 has a main radiating patch 9, the fifth dielectric substrate 5 has a square-shaped slot as the antenna feed slot, and the sixth dielectric substrate 6 has a feed microstrip line 10, which is a cross-shaped microstrip line.

[0030] The patch 7 is a circular patch with multiple notches on its edge to form additional current paths, change the equivalent electrical length, thereby exciting resonance at multiple frequency points and expanding the antenna bandwidth. The positions of the multiple notches are centrally symmetrical, ensuring that the reverse induced current generated on the resonant ring 8 can uniformly and symmetrically cancel the current component on the patch 7, thereby effectively optimizing the axial ratio at various scanning angles.

[0031] In this embodiment, the number of notches in patch 7 is 4.

[0032] The resonant ring 8 is a circular metal ring with multiple openings to adjust the magnitude of its reverse current. The induced current in the resonant ring 8 flows along the shortest loop. When openings are created in the ring, the current is forced to flow around the edges of the openings, effectively increasing the effective current path and thus altering the equivalent inductance (L) of the resonant ring. A capacitance (C) is formed between the openings and the metal edges on both sides of the resonant ring 8. This capacitance, at the operating frequency of the antenna corresponding to the LC resonant point, induces a reverse current of suitable strength to achieve optimal cancellation and ultimately optimize the axial ratio.

[0033] The multiple openings are centrally symmetrically positioned to ensure that the reverse current induced on the resonant ring 8 is also symmetrical. This reverse current cancels out the current component on patch 7, thereby optimizing the axial ratio during large-angle scanning. If the openings are asymmetrical, it will cause unbalanced induced current, disrupting the overall current distribution of the antenna and potentially degrading polarization performance.

[0034] The opening of the resonant ring 8 corresponds one-to-one with the notch of the patch 7. The opening of the resonant ring 8 and its corresponding notch are located on the same straight line passing through the center of the patch 7. This ensures that the "reverse current" generated by the resonant ring 8 can most effectively act on the key position on the patch 7 where the current changes. It exerts its influence on the place where adjustment is most needed, thereby achieving the best cancellation effect and exciting the most suitable reverse current to optimize the axial ratio.

[0035] In this embodiment, the number of openings in the resonant ring 8 is 4.

[0036] The difference in polarization components excited during large-angle scanning is one of the reasons for the deterioration of the axial ratio. By loading a resonant ring on the patch, a reverse current can be generated to cancel the current of the patch's X and Y axis components. When scanning at large angles, the X-axis component current projected onto Retheta is more canceled than the corresponding Rephi of the Y axis, reducing the difference between the two polarization components and thus optimizing the axial ratio.

[0037] Specifically, when scanning to a large angle, the coupling energy corresponding to the slots of the antenna element generating X-polarized and Y-polarized components exhibits differences: the Retheta component reflects the projection of the patch X-axis current onto the scanning direction, while the Rephi component characterizes the direct radiation contribution of the patch Y-axis current. The electric field responses of the X-axis and Y-axis patch currents differ at the scanning angle. Specifically, when the beam scans to theta = 60° and phi = 0°, the X-axis current (Rex) exhibits a nonlinear mapping relationship with the Retheta component, while the Y-axis current (Rey) is strictly equivalent to the Rephi component. Therefore, when scanning to a large angle, the X-axis component current projects onto the Retheta component more than the Y-axis corresponding Rephi component cancels it out, reducing the difference between the two polarization components and thus optimizing the axial ratio.

[0038] In one embodiment, taking a 32*32 starchain antenna scanning to a Theta of 65° at 14.5 GHz as an example, Rephi, Retheta, Rex, Rey are as follows: Figure 3 , Figure 4 As shown, Rephi and Rey are equal, with values ​​of 66.53 dB and 67.01 dB respectively with and without a resonant ring. Without a resonant ring, Retheta and Rex are 70.56 dB and 63.07 dB, a difference of 7.49 dB; with a resonant ring, Retheta and Rex are 68.97 dB and 61.48 dB, also a difference of 7.49 dB, indicating a nonlinear mapping relationship. The projection of Retheta onto Rex differs by approximately 7.5 dB. Adding a resonant ring cancels out the Rex component, resulting in a 1.96 dB difference between Retheta and Rephi, compared to a 4.03 dB difference without a resonant ring.

[0039] Figure 5 This diagram illustrates the current distribution without a resonant ring. It shows the surface current distribution with only the main patch during one excitation signal cycle (from Phase = 0deg to Phase = 350deg). The direction and color of the arrows represent the direction and intensity of the current (warmer colors indicate greater intensity). As can be seen, the current is mainly concentrated on the circular patch. With the phase change, the direction and intensity of the current change periodically, forming a rotating current field that radiates circularly polarized electromagnetic waves.

[0040] Figure 6 This diagram illustrates the current distribution after adding a resonant ring. It shows the surface current distribution under the same conditions. (Comparison) Figure 5 The most significant difference is the presence of a noticeable current in the outer resonant ring. According to Lenz's law, the changing magnetic field of the current on the patch induces a current in the resonant ring in the opposite direction to counteract this change. When the dominant current on the patch points in one direction (e.g., in the 0-180 degree half-cycle, equivalent to the negative XY axis), the induced current in the resonant ring points in the opposite direction (the positive XY axis). In the other half-cycle, from 180 to 360 degrees, the situation is reversed. The current in the resonant ring is equivalent to canceling the current in the positive XY axis, thus adjusting the polarization components. This reverse current acts as a cancellation mechanism. Since the currents in the X and Y directions contribute differently to the final far-field radiation during large-angle antenna scanning (there is a projection relationship), the "reverse current" generated by the resonant ring can unequally cancel these two components, causing the amplitudes of the two polarization components (rETheta and rEPhi) with large differences after projection to tend to be consistent, thereby optimizing the axial ratio.

[0041] Microstrip antenna axis without resonant ring, for exampleFigure 7 As shown, the axis of a microstrip antenna with a resonant ring added is, for example... Figure 8 As shown, when the scan reaches 65 degrees, the axial ratio value with the addition of the resonant ring is 1.97dB, which is 4.63dB lower than that without the resonant ring, demonstrating a significant effect in axial ratio optimization.

[0042] The above-described embodiments further illustrate the purpose, technical solution, and advantages of the present invention. It should be understood that the above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning, comprising multiple antenna elements, each antenna element having a patch (7) on its upper surface, characterized in that, Each antenna element is also provided with a resonant ring (8) on its upper surface, which is arranged around the patch (7).

2. The phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 1, characterized in that, The edge of the patch (7) has multiple notches, and the positions of the multiple notches are symmetrical.

3. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning as described in claim 2, characterized in that, The resonant ring (8) has multiple openings, and the positions of the multiple openings are centrally symmetrical.

4. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 3, characterized in that, The opening of the resonant ring (8) corresponds one-to-one with the notch of the patch (7), and the opening of the resonant ring (8) and its corresponding notch are located on the same straight line passing through the center of the patch (7).

5. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 1, characterized in that, The antenna unit includes a first dielectric substrate (1), a patch (7) and a resonant ring (8) disposed on the upper surface of the first dielectric substrate (1).

6. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 2, characterized in that, A second dielectric substrate (2) is provided below the first dielectric substrate (1), and the second dielectric substrate (2) is an air dielectric substrate.

7. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 6, characterized in that, A third dielectric substrate (3) is provided below the second dielectric substrate (2), and the third dielectric substrate (3) is provided with a main radiating patch (9).

8. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 7, characterized in that, A fourth dielectric substrate (4) is provided below the third dielectric substrate (3), and the fourth dielectric substrate (4) is an air dielectric substrate.

9. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 8, characterized in that, A fifth dielectric substrate (5) is provided below the fourth dielectric substrate (4), and the fifth dielectric substrate (5) has a square-shaped slit.

10. A phased array antenna for solving the problem of axial ratio degradation during large-angle scanning according to claim 9, characterized in that, A sixth dielectric substrate (6) is provided below the fifth dielectric substrate (5), and a feed microstrip line (10) is provided on the sixth dielectric substrate (6).

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