Low profile dual-band dual-polarized compound phased array antenna array

Abstract

The present application relates to a kind of low profile dual-frequency dual-polarized composite phased array antenna array, the antenna array includes 2m low profile dual-frequency composite antenna line array, each low profile dual-frequency composite antenna line array includes 2n low profile dual-frequency composite antenna subarray, m and n are all natural numbers.Each of the low profile dual-frequency composite antenna subarray includes: mixed pressure microstrip structure;Metal base, located below mixed pressure microstrip structure and connected therewith, and at least 4 Ku wave band antenna structures and 1 X wave band antenna structure are provided in each of the low profile dual-frequency composite antenna subarray.The present application can be applied to circular polarization application scene, effectively solve the problem that only linear polarization design exists in traditional composite phased array antenna, profile is too high, aperture utilization is low.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and more specifically to a low-profile dual-frequency dual-polarization composite phased array antenna array. Background Technology

[0002] Frequency / polarization composite antenna arrays utilize a high-density, common-aperture antenna layout within a limited antenna aperture to replace two separate frequency bands or two polarizations, thereby achieving higher aperture utilization and structural integration. Compared to separate array solutions, common-aperture composite antenna arrays offer advantages such as high efficiency, low cost, integration, and lightweight design, making them highly promising for applications in wireless communication and radar, and thus a research hotspot in recent years. Current research on composite phased array antenna designs using common microstrip patches, slot coupling, or vertical dipoles as antenna forms largely focuses on linear polarization applications. However, in recent years, phased array antenna arrays characterized by dual-band composite and dual-rotational circular polarization composite designs have increasingly become a research hotspot. To address this need, related research has proposed designs based on waveguide antennas and dielectric antennas; however, these often require the introduction of additional circular polarizer structures, leading to excessive antenna profile height and weight. For designs involving bridges, power dividers, or active devices, this significantly increases the complexity and difficulty of antenna product design and manufacturing, while also noticeably increasing the cost of antenna products, thus greatly limiting their practical engineering applications.

[0003] To meet practical engineering needs, there is an urgent need to propose a low-profile, integrated, low-cost manufacturing dual-frequency dual-polarization composite phased array antenna design that is suitable for circular polarization applications.

[0004] It is understood that the above statements only provide background information related to the present invention and do not necessarily constitute prior art. Summary of the Invention

[0005] The purpose of this invention is to provide a low-profile dual-frequency dual-polarization composite phased array antenna array that is applicable to circular polarization application scenarios. It effectively solves the problems of traditional composite phased array antennas, such as design only for linear polarization, excessively high profile, and low aperture utilization, and provides strong support for applications such as intelligent communication systems and anti-interference navigation systems.

[0006] To achieve the above objectives, the present invention provides a low-profile dual-frequency dual-polarization composite phased array antenna array, wherein the antenna array comprises 2m low-profile dual-frequency composite antenna linear arrays, and each low-profile dual-frequency composite antenna linear array comprises 2n low-profile dual-frequency composite antenna subarrays, where m and n are both natural numbers.

[0007] Each of the aforementioned low-profile dual-frequency composite antenna subarrays comprises: a hybrid microstrip structure; and a metal base located below and connected to the hybrid microstrip structure.

[0008] Each of the aforementioned low-profile dual-frequency composite antenna subarrays is provided with at least 4 Ku-band antenna structures and 1 X-band antenna structure.

[0009] Furthermore, the hybrid microstrip structure includes the following layers of the same size: a Ku-band radiation layer; a Ku-band floor layer located below and connected to the Ku-band radiation layer; an X-band radiation layer located below and connected to the Ku-band floor layer; and an X-band feed layer located below and connected to the X-band radiation layer.

[0010] Furthermore, the Ku-band radiation layer comprises: an upper microstrip board; and at least four Ku-band patch patterns located on the upper surface of the upper microstrip board.

[0011] Each Ku-band patch pattern includes: a circular ring pattern; a feed pattern having a Ku probe metallization via through the upper microstrip board, the feed pattern being located inside the circular ring pattern, and the portion of the feed pattern near the circular ring pattern being an arc-shaped portion, with an arc-shaped gap between the arc-shaped portion and the circular ring pattern; and two parasitic patterns located outside the circular ring pattern, and arranged 180° rotationally symmetrically with respect to the Ku probe metallization via, each parasitic pattern comprising at least two layers of spaced, gradually varying arc-shaped patterns.

[0012] The circular pattern, parasitic pattern, and Ku probe metallized via share the same center.

[0013] Furthermore, the Ku-band ground plane layer comprises: a middle microstrip board; and at least four Ku-band ground plane patterns located on the upper surface of the middle microstrip board, the number of which corresponds to the number of the Ku-band patch patterns.

[0014] Each of the Ku-band floor patterns includes a first Ku via penetrating the middle microstrip board. The first Ku via is positioned aligned with the metallized vias of each Ku probe. A gap formed by etching is also provided between two adjacent Ku-band floor patterns.

[0015] Furthermore, the X-band radiation layer includes: a lower microstrip board; and an X-band copper cladding layer located on the upper surface of the lower microstrip board 131.

[0016] The X-band copper cladding layer includes: at least four Ku-band second vias, the number of which corresponds to the number of Ku-band patch patterns. Each Ku-band second via penetrates the lower microstrip board and is positioned aligned with the metallized vias of each Ku probe. A fractal slot is also included, which is inclined at 45°. The fractal slot is a second-order fractal pattern with the same slot width in any branch and a fixed angle between any upper and lower branches.

[0017] Furthermore, the X-band feed layer comprises: a bottom microstrip board; a microstrip feed line located on the upper surface of the bottom microstrip board; and a microstrip ground plane located on the lower surface of the bottom microstrip board.

[0018] The microstrip ground plane has at least four Ku third vias, the number of which corresponds to the number of Ku-band patch patterns. The Ku third vias penetrate the bottom microstrip board and are positioned aligned with each Ku probe metallization via. The end of the microstrip feed line has an X probe via, which penetrates both the bottom microstrip board and the microstrip ground plane.

[0019] Furthermore, the metal base includes: an X-threaded hole, positioned aligned with the X-probe via; and at least four Ku-threaded holes, the number of which corresponds to the number of the Ku-band patch pattern, and each positioned aligned with the metallized via of the Ku probe.

[0020] Furthermore, the hybrid microstrip structure also includes: at least four Ku-band feed connectors, each of which is fastened to a metal base through a Ku-threaded hole and passes sequentially through a third Ku-via, a second Ku-via, a first Ku-via, and a Ku-probe metallized via to form a Ku-band antenna structure; and an X-band feed connector, which is fastened to a metal base through an X-threaded hole and passes through an X-probe via to form an X-band antenna structure.

[0021] Furthermore, the antenna array can adopt a full array layout or a sparse optimized layout.

[0022] Furthermore, the antenna array can be circularly polarized and rotated.

[0023] Specifically, rotating the two parasitic patterns in each Ku-band patch pattern by 90° around the center of the Ku probe via can reverse the circular polarization rotation direction of the Ku-band antenna structure; rotating the fractal slot in the X-band copper layer by 90° around its center can reverse the circular polarization rotation direction of the X-band antenna structure.

[0024] In summary, the low-profile dual-frequency dual-polarization composite phased array antenna array provided by this invention has the advantages of low antenna profile, high integration, and high aperture utilization. It also effectively ensures the expansion of the antenna's operating bandwidth and supports flexible design and adjustment of the Ku-band antenna rotation and X-band antenna rotation, providing strong support for applications such as intelligent communication systems and anti-interference navigation systems. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the antenna array of the present invention;

[0026] Figure 2 This is a schematic diagram of the overall dual-frequency composite antenna subarray of the present invention;

[0027] Figure 3 This is a 3D exploded view of the hybrid microstrip structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the Ku-band radiation layer of the present invention;

[0029] Figure 5 This is a schematic diagram of the Ku-band floor layer of the present invention;

[0030] Figure 6 This is a schematic diagram of the X-band radiation layer of the present invention;

[0031] Figure 7(a) is a top schematic diagram of the X-band feed layer of the present invention, and Figure 7(b) is a bottom schematic diagram of the X-band feed layer of the present invention;

[0032] Figure 8 This is a schematic diagram of the metal base of the present invention;

[0033] Figure 9 This is a schematic diagram of the structure of the Ku-band antenna of the present invention after rotational circular polarization.

[0034] Figure 10 This is a schematic diagram of the structure of the X-band antenna of the present invention after rotational circular polarization. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0036] Example 1

[0037] like Figure 1As shown, this invention provides a low-profile dual-frequency dual-polarization composite phased array antenna array (hereinafter referred to as "antenna array"). The antenna array consists of eight identical low-profile dual-frequency composite antenna linear arrays A, which are connected sequentially from top to bottom. Furthermore, each dual-frequency composite antenna linear array A consists of eight identical dual-frequency composite antenna subarrays B, which are connected sequentially from left to right.

[0038] It should be noted that the above embodiment describes an 8×8 antenna array, which is only a preferred embodiment. In other embodiments of the present invention, the antenna array can be a 2n×2m structure, where n and m are natural numbers. That is, the number of both dimensions of the antenna array must be an integer multiple of 2, i.e., an even number. Therefore, in summary, the antenna array consists of 2m low-profile dual-frequency composite antenna linear arrays A, and each dual-frequency composite antenna linear array A is composed of 2n dual-frequency composite antenna subarrays B.

[0039] Furthermore, the number of the two dimensions of the antenna array is independent of each other, and the specific value depends on the actual performance requirements of the antenna array. Therefore, in addition to the 8×8 structure described above, the antenna array of the present invention can also be a 2×4 structure, or a 6×10 structure, etc.

[0040] like Figure 2 As shown, the dual-frequency composite antenna subarray B includes: a hybrid microstrip structure 1; and a metal base 2 located below and connected to the hybrid microstrip structure 1. The hybrid microstrip structure 1 and the metal base 2 are positioned and secured together by welding.

[0041] Furthermore, such as Figure 3 As shown, the hybrid microstrip structure 1 has four layers, from top to bottom: a Ku-band radiation layer 11; a Ku-band floor layer 12, located below and connected to the Ku-band radiation layer 11; an X-band radiation layer 13, located below and connected to the Ku-band floor layer 12; and an X-band feed layer 14, located below and connected to the X-band radiation layer 13. The four layers of the hybrid microstrip structure 1 have the same length and width dimensions and can be fabricated into a single unit using microstrip board hybrid pressing technology, i.e., the hybrid microstrip structure 1.

[0042] Furthermore, such as Figure 4 As shown, the Ku-band radiation layer 11 includes: an upper microstrip board 111; and at least four identical Ku-band patch patterns 112 located on the upper surface of the upper microstrip board 111. In this embodiment, four Ku-band patch patterns 112 will be used as an example for description.

[0043] Each Ku-band patch pattern 112 includes: a ring pattern 1121, a feed pattern 1122, a parasitic pattern 1123, an arc-shaped slot 1124, and a Ku probe metallization via 1125. Each feed pattern 1122 has a Ku probe metallization via 1125 penetrating the upper microstrip board 111. The feed pattern 1122 is located inside the ring pattern 1121, and its portion near the ring pattern 1121 is an arc-shaped portion. An arc-shaped slot 1124 is provided between the arc-shaped portion of the feed pattern 1122 and the ring pattern 1121. The arc-shaped slot 1124 can effectively improve the antenna's feed rate. Electrical matching adjustment capability expands the bandwidth performance of the Ku-band antenna; the parasitic pattern 1123 is a gradually changing length of at least two layers of spaced arc-shaped pattern, which can effectively improve the bandwidth performance of the Ku-band antenna; each Ku-band patch pattern 112 includes two parasitic patterns 1123 located outside the annular pattern 1121, and the two parasitic patterns 1123 are arranged in a 180° rotational symmetry with respect to the Ku probe metallization via 1125, thereby generating effective circular polarization radiation; the annular pattern 1121, the parasitic pattern 1123 and the Ku probe metallization via 1125 have the same center.

[0044] The number of layers in the parasitic pattern 1123 is related to the impedance matching adjustment capability; using two or more arc-shaped layers can achieve better performance. However, it is also limited by the spatial size of the Ku-band patch pattern 112. Therefore, in a preferred embodiment, a method such as... Figure 4 The parasitic pattern 1123 is constructed by three layers of arc-shaped spacing, which can achieve good impedance matching adjustment performance and meet the space constraints.

[0045] Furthermore, such as Figure 5 As shown, the Ku-band floor layer 12 includes: a middle microstrip board 121; and at least four identical Ku-band floor patterns 122 located on the upper surface of the middle microstrip board 121. The specific number of Ku-band floor patterns 122 corresponds to the number of Ku-band patch patterns 112. Therefore, in this embodiment, four Ku-band floor patterns 122 are used as an example for description.

[0046] Each Ku-band floor pattern 122 includes a first Ku-band via 1221 penetrating the middle microstrip board 121, with each first Ku-band via 1221 aligned with a metallized via 1125 for each Ku probe. A cross-shaped gap 1222 is etched between two adjacent Ku-band floor patterns 122, allowing X-band electromagnetic wave radiation from the lower layer of the Ku-band floor layer 12 to pass through, thus forming a rectangular metamaterial lattice structure. By utilizing this metamaterial lattice structure, the bandwidth of the Ku-band antenna can be further effectively extended, and the mutual coupling suppression between array elements can be effectively improved.

[0047] Furthermore, such as Figure 6 As shown, the X-band radiation layer 13 includes: a lower microstrip board 131; and an X-band copper cladding layer 132 located on the upper surface of the lower microstrip board 131.

[0048] The X-band copper cladding layer 132 includes at least four Ku-band second vias 1321 and fractal slots 1322. The specific number of Ku-band second vias 1321 corresponds to the number of Ku-band patch patterns 112. Therefore, in this embodiment, four Ku-band second vias 1321 are used as an example for description. Each Ku-band second via 1321 penetrates the lower microstrip board 131, and its position is aligned with each Ku-band probe metallized via 1125. The fractal slots 1322 are generally tilted at 45° to achieve circularly polarized wave radiation. The fractal slot 1322 is a second-order fractal pattern with the same slot width in any branch and a fixed angle between any upper and lower branches. Compared with the traditional straight strip slot structure, the structure of the fractal slot 1322 can effectively expand the bandwidth of the X-band antenna.

[0049] Furthermore, as shown in Figures 7(a) and 7(b), the X-band feed layer 14 includes: a bottom microstrip board 141; a microstrip feed line 142 located on the upper surface of the bottom microstrip board 141; and a microstrip ground plane 143 located on the lower surface of the bottom microstrip board 141.

[0050] As shown in Figure 7(b), at least four Ku third vias 1431 are provided on the microstrip ground plane 143; the specific number of Ku third vias 1431 corresponds to the number of Ku-band patch patterns 112. Therefore, in this embodiment, four Ku third vias 1431 are used as an example for description. The Ku third vias 1431 penetrate the bottom microstrip board 141, and their positions are aligned with each Ku probe metallization via 1125. As shown in Figure 7(a), the upper half of the microstrip feed line 142 is elongated, with an X probe via 1421 at its end; the X probe via 1421 penetrates the bottom microstrip board 142 and the microstrip ground plane 143.

[0051] Furthermore, such as Figure 8 As shown, the metal base 2 includes: one X-threaded hole 22, which is aligned with the X-probe via 1421; and at least four Ku-threaded holes 21. The specific number of Ku-threaded holes 21 corresponds to the number of Ku-band patch patterns 112. Therefore, in this embodiment, four Ku-threaded holes 21 are used as an example for description, and their positions are aligned with the metallized vias 1125 of each Ku-probe.

[0052] Furthermore, such as Figure 8 As shown, the hybrid microstrip structure 1 further includes at least four Ku-band feed connectors 23 and X-band feed connectors 24. In this embodiment, to correspond with the above description, four Ku-band feed connectors 23 are still used as an example. Each Ku-band feed connector 23 is fastened to a metal base through a Ku-threaded hole 21, and passes through a Ku-third via 1431, a Ku-second via 1321, a Ku-first via 1221, and a Ku-probe metallized via 1125 in sequence to form a Ku-band antenna structure, thereby feeding the Ku-band patch pattern 112. The X-band feed connector 24 is fastened to a metal base through an X-threaded hole 22, and passes through an X-probe via 1421 to form an X-band antenna structure, thereby feeding the microstrip feed line 142.

[0053] In the preferred embodiment 1 of the present invention, the low-profile dual-frequency composite phased array antenna array adopts a full array layout. It can be understood that each dual-frequency composite antenna subarray B contains 4 Ku-band antenna structures and 1 X-band antenna structure.

[0054] Furthermore, in other preferred embodiments of the present invention, based on the requirements of the phased array antenna gain and radiation pattern, different numbers, shapes, and directions of antenna arrays can be combined based on the dual-frequency composite antenna subarray B. However, the minimum structure of each dual-frequency composite antenna subarray B must satisfy the requirement of including 4 Ku-band antenna structures and 1 X-band antenna structure.

[0055] Example 2

[0056] In another preferred embodiment 2 of the present invention, a sparse distribution design is performed on the low-profile dual-frequency dual-polarization composite phased array antenna array described in preferred embodiment 1. The antenna-related features of the two preferred embodiments are basically the same, the difference being that preferred embodiment 2 of the present invention performs sparse distribution optimization on the Ku-band antenna structure. After the sparse distribution optimization, for all Ku-band antenna structures that are removed by the sparse distribution, the Ku-band patch pattern 112 at the corresponding position does not need to be set; the Ku probe via 1125 at the corresponding position also does not need to be set; the Ku first via 1121, the Ku second via 1321, and the Ku third via 1431 at the corresponding position also do not need to be set; the Ku threaded hole 21 at the corresponding position also does not need to be set.

[0057] Example 3

[0058] Preferred embodiment 3 of the present invention adjusts and combines the circular polarization rotation direction of the low-profile dual-frequency dual-polarization composite phased array antenna array described in preferred embodiment 1. The antenna-related features of the two preferred embodiments are basically the same, the difference being that in preferred embodiment 3 of the present invention, such as… Figure 9 As shown, rotating the parasitic pattern 1123 by 90° around the center of the Ku probe via 1125 can reverse the circular polarization rotation direction of the Ku-band antenna structure; as Figure 10 As shown, rotating the fractal slit 1322 90° around its center can reverse the circular polarization rotation direction of the X-band antenna structure; the rotation direction designs of the two frequency bands mentioned above do not interfere with each other.

[0059] In summary, a low-profile dual-frequency dual-polarization composite phased array antenna array possesses advantages such as low antenna profile, high integration, and high aperture utilization. Furthermore, it effectively ensures the expansion of the antenna's operating bandwidth and supports flexible design and adjustment of the Ku-band and X-band antenna rotation directions. These characteristics effectively solve the problems of traditional composite phased array antennas, which often only target linear polarization design, have excessively high profiles, and low aperture utilization, providing strong support for applications such as intelligent communication systems and anti-jamming navigation systems. Based on the principle of antenna size reduction, the design concept and implementation scheme of this invention can be extended to the design of low-profile dual-frequency dual-polarization composite phased array antennas with equivalent characteristics across any frequency band.

[0060] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A low-profile dual-frequency dual-polarization composite phased array antenna array, characterized in that, The antenna array comprises 2m low-profile dual-frequency composite antenna arrays, and each low-profile dual-frequency composite antenna array comprises 2n low-profile dual-frequency composite antenna subarrays, where m and n are both natural numbers. Each of the aforementioned low-profile dual-frequency composite antenna subarrays comprises: a hybrid microstrip structure; and a metal base located below and connected to the hybrid microstrip structure. Each of the aforementioned low-profile dual-frequency composite antenna subarrays is provided with at least 4 Ku-band antenna structures and 1 X-band antenna structure. The hybrid microstrip structure comprises components of the same size: Ku-band radiation layer; Ku-band floor layer, located below and connected to the Ku-band radiation layer; X-band radiation layer, located below and connected to the Ku-band floor layer; X-band feed layer, located below and connected to the X-band radiation layer. The Ku-band radiation layer comprises: an upper microstrip board; at least four Ku-band patch patterns located on the upper surface of the upper microstrip board; each Ku-band patch pattern comprises: A circular ring pattern; a feed pattern having a Ku probe metallized via through the upper microstrip board; the feed pattern is located inside the circular ring pattern, and the part of it close to the circular ring pattern is an arc-shaped portion, with an arc-shaped gap between the arc-shaped portion and the circular ring pattern; The X-band radiation layer comprises: a lower microstrip board; and an X-band copper plating layer located on the upper surface of the lower microstrip board; the X-band copper plating layer comprises: The fractal gap is inclined at 45°; the fractal gap is a second-order fractal shape, which has the same gap width in any branch and the included angle between any upper and lower branches is fixed. The X-band feed layer comprises: a bottom microstrip board; a microstrip feed line located on the upper surface of the bottom microstrip board; and a microstrip ground plane located on the lower surface of the bottom microstrip board.

2. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 1, characterized in that, Each of the Ku-band patch patterns also includes: Two parasitic patterns are located outside the annular pattern and are arranged 180° rotationally symmetrically with respect to the metallized via of the Ku probe; each parasitic pattern contains at least two layers of spaced arc-shaped patterns with gradually varying lengths. The circular pattern, parasitic pattern, and Ku probe metallized via have the same center.

3. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 2, characterized in that, The Ku-band ground plane layer comprises: a middle microstrip board; at least four Ku-band ground plane patterns located on the upper surface of the middle microstrip board; the number of Ku-band ground plane patterns corresponds to the number of Ku-band patch patterns. Each of the Ku-band floor patterns includes a first Ku via penetrating the middle microstrip board, wherein the first Ku via is positioned aligned with the metallized vias of each Ku probe. A gap formed by etching is also provided between two adjacent Ku-band floor patterns.

4. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 3, characterized in that, The X-band copper cladding layer further includes: At least four Ku-band second vias are provided, the number of which corresponds to the number of Ku-band patch patterns. Each Ku-band second via penetrates the lower microstrip board and is positioned aligned with the metallized vias of each Ku probe.

5. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 4, characterized in that, At least four Ku third vias are provided on the microstrip floor; the number of Ku third vias corresponds to the number of Ku-band patch patterns; the Ku third vias penetrate the bottom microstrip board and are positioned aligned with the metallized vias of each Ku probe; An X-probe via is provided at the end of the microstrip feed line; the X-probe via penetrates the bottom microstrip board and the microstrip ground plane.

6. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 5, characterized in that, The metal base includes: The X threaded hole is positioned so that it is aligned with the X probe through hole. At least four Ku threaded holes are provided, the number of which corresponds to the number of Ku-band patch patterns, and their positions are aligned with the metallized vias of each Ku probe.

7. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 6, characterized in that, The hybrid microstrip structure further includes: At least four Ku-band feed connectors are provided. Each Ku-band feed connector is fastened to a metal base through a Ku threaded hole and passes through a third Ku via, a second Ku via, a first Ku via, and a metallized Ku probe via in sequence to form a Ku-band antenna structure. The X-band feed connector is fastened to the metal base through the X-threaded hole and passes through the X-probe through hole to form an X-band antenna structure.

8. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 1, characterized in that, The antenna array can be a full array layout or a sparse optimized layout.

9. The low-profile dual-frequency dual-polarization composite phased array antenna array as described in claim 7, characterized in that, The antenna array can be circularly polarized and rotated. Specifically, rotating the two parasitic patterns in each Ku-band patch pattern by 90° along the center of the Ku probe via can reverse the circular polarization rotation of the Ku-band antenna structure. Rotating the fractal slot in the X-band copper layer 90° around its center can reverse the circular polarization rotation of the X-band antenna structure.

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