Integrated low-profile multi-beam circularly polarized folded transmission array antenna

Abstract

This invention discloses an integrated low-profile multi-beam circularly polarized folded transmission array antenna. The antenna includes a circularly polarized transmission array, a circularly polarized reflection array, and a planar integrated feed. The circularly polarized transmission array is placed directly above the circularly polarized reflection array, with a cutout at the center of the circularly polarized reflection array. The planar integrated feed is embedded in the center of the circularly polarized reflection array. The circularly polarized transmission array and the circularly polarized reflection array each include several tunable phase-transmitting transmission units and tunable phase-reflecting units, and are simultaneously phase-tuned. Under the conditions of multi-beam radiation and low profile, the phase-tuning of the circularly polarized transmission array compensates for the path phase delay of the circularly polarized spherical electromagnetic wave and the principal value of the phase angle of the complex linear superposition of each radiated beam, thereby generating multi-beam radiation. The circularly polarized reflection array is used to compensate for the path phase change of the circularly polarized electromagnetic wave caused by the reduction in profile height, so as to work in conjunction with the phase-tuning compensation of the circularly polarized transmission array to achieve a reduction in profile height.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and in particular relates to a low-profile multi-beam circularly polarized folded transmission array antenna suitable for mobile platforms or space-constrained environments. Background Technology

[0002] With the rapid development of modern wireless communication technologies, especially in satellite communication, radar detection, and fifth / sixth generation mobile communication, the performance requirements for antenna systems are becoming increasingly stringent. These applications not only require antennas to have high gain and multi-beam coverage capabilities, but also place higher demands on system integration, profile height, and polarization. Especially for space-constrained platforms such as airborne, spaceborne, and missile-borne systems, low-profile antennas with multi-functional integration characteristics have become an urgent need.

[0003] Folded transmission array antennas, combining the high gain of transmission arrays with the low profile of folded structures, have attracted widespread attention in recent years. A typical structure includes a parallel transmission array, a polarized rotating reflector array, and a feed. Electromagnetic waves radiate from the feed, refract multiple times between the transmission and reflector arrays, and finally exit from the transmission array, forming a high-gain beam. Compared to traditional transmission arrays, the folded structure can reduce the antenna profile height by about one-third, showing significant application potential in space-constrained platforms. However, existing folded transmission array antennas still suffer from low feed integration and difficulties in implementing multi-beam designs. In traditional designs, the feed is often independently positioned at the center of the reflector or in a suspended space, increasing the longitudinal dimension and requiring high assembly precision. Phased array solutions are costly and power-consuming, and multi-feed solutions are difficult to integrate with low-profile structures. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention proposes an integrated low-profile multi-beam circularly polarized folded transmission array antenna. It employs a coplanar integrated design of the feed and reflector arrays, achieving extreme simplification of the manufacturing process. By utilizing the independent control of the orthogonal components of circular polarization through the reflector array, precise control and polarization conversion of the circularly polarized wave are achieved. Furthermore, through a dual-phase compensation method, the transmission and reflector arrays work synergistically, achieving four beams while further reducing the profile height. This invention offers advantages such as high integration, low profile, flexible beams, controllable circular polarization, and low manufacturing cost.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] An integrated low-profile multi-beam circularly polarized folded transmission array antenna is provided. The antenna includes a circularly polarized transmission array (1), a circularly polarized reflection array (2), and a planar integrated feed source (3). The circularly polarized transmission array (1) is placed directly above the circularly polarized reflection array (2). The circularly polarized reflection array (2) has a hollow center. The planar integrated feed source (3) is embedded in the center of the circularly polarized reflection array (2). The circularly polarized transmission array (1) includes several periodically arranged tunable phase-transmitting transmission units (4); the circularly polarized reflection array (2) includes several periodically arranged tunable phase-reflecting units (12); the circularly polarized transmission array (1) and the circularly polarized reflection array (2) are simultaneously phase-modulated, i.e., the dual-phase compensation method; under the conditions of multi-beam radiation and low profile, the circularly polarized transmission array (1) compensates for the path phase delay of the circularly polarized spherical electromagnetic wave and the principal value of the phase angle of the complex linear superposition phase of each radiation beam to generate multi-beam radiation; the circularly polarized reflection array (2) is used to compensate for the change in the path phase of the circularly polarized electromagnetic wave caused by the reduction in profile height, so as to cooperate with the phase-modulation compensation of the circularly polarized transmission array (1) to achieve the reduction in profile height.

[0007] Furthermore, the adjustable phase transceiver unit (4) includes an upper metal patch layer (5), an upper dielectric substrate layer (6), an intermediate metal ground layer (7), a first adhesive layer (8), a lower dielectric substrate layer (9), and a lower metal patch layer (10) stacked sequentially from top to bottom; the metal via (11) is cylindrical and located at the center of the adjustable phase transceiver unit (4), penetrating from the upper metal patch layer (5) to the lower metal patch layer (9); under the polarization matching condition of the lower metal patch layer (10), the metal via (11) transmits the induced current generated by the lower metal patch layer (10) to the upper metal patch layer (5) to excite the upper metal patch layer. The upper metal patch layer (5) radiates left-hand circularly polarized electromagnetic waves; the upper metal patch layer (5) is rectangular and etched with asymmetric U-shaped slots; the middle metal ground layer (7) has a circular slot etched in the center to isolate the upper metal patch layer (5) and the lower metal patch layer (10); the lower metal patch layer (10) is rectangular and etched with asymmetric U-shaped slots to receive right-hand circularly polarized electromagnetic waves and reflect left-hand circularly polarized electromagnetic waves, i.e., polarization matching and polarization mismatch; the adjustable phase transceiver unit (4) achieves a phase change of 0°-360° by rotating the upper metal patch layer (5) counterclockwise about the metal through hole (11) by 0°-360°.

[0008] Furthermore, the adjustable phase reflection unit (12) includes a top metal reflective patch layer (13), a first top dielectric substrate layer (14), an intermediate metal ground layer (15), a second adhesive layer (16), a first bottom dielectric substrate layer (17), and a bottom metal phase-modulation patch layer stacked sequentially from top to bottom; the top metal reflective patch layer (13) is square; a circular gap is etched in the center of the intermediate metal ground layer (15); the bottom metal phase-modulation patch layer includes an x-direction phase-modulation delay line (18) and a y-direction phase-modulation delay line (19); the x-direction phase-modulation delay line (18) is rectangular and extends towards the positive half-axis; the y-direction phase-modulation delay line (19) is rectangular and extends towards the negative half-axis; the x-direction metal via (20) is cylindrical and connected The top metal reflective patch layer (13) and the x-direction phase-modulation delay line (18) are connected to transmit the x-component induced current generated by the top metal reflective patch layer (13) to the x-direction phase-modulation delay line (18) to achieve phase modulation of the x-component of the circularly polarized electromagnetic wave; the y-direction metal via (21) is cylindrical and connects the top metal reflective patch layer (13) and the y-direction phase-modulation delay line (19) to transmit the y-component induced current generated by the top metal reflective patch layer (13) to the y-direction phase-modulation delay line (19) to achieve phase modulation of the y-component of the circularly polarized electromagnetic wave; the adjustable phase reflection unit (12) achieves a phase change of 0°-360° by simultaneously adjusting the lengths of the x-direction phase-modulation delay line (18) and the y-direction phase-modulation delay line (19).

[0009] Furthermore, the planar integrated feed (3) has the same stacked structure as the tunable phase reflection unit (12), including a top metal radiating patch layer (22), a second top dielectric substrate layer (23), an intermediate metal coupling ground layer (24), a third adhesive layer (25), a second bottom dielectric substrate layer (26), and a bottom metal feed layer (27) stacked sequentially from top to bottom; the top metal radiating patch layer (22) is circular; the intermediate metal coupling ground layer (24) has a star-shaped slot etched in the center; the bottom metal feed layer (27) is a ring microstrip line with a port 1 for external matching load and a port 2 for external radio frequency signal source at both ends; the planar integrated feed (3) excites the star-shaped slot of the intermediate metal coupling ground layer (24) in a counterclockwise direction through the excitation port 2, radiating left-hand circularly polarized electromagnetic waves.

[0010] Furthermore, the upper dielectric substrate layer (6) and the lower dielectric substrate layer (9) are configured as F4BTM350 with a thickness of 1.52 mm, a relative permittivity of 3.5, and a tangent loss angle of 0.0025; the first adhesive layer (8) is configured as RO4450F with a thickness of 0.10 mm, a relative permittivity of 3.52, and a tangent loss angle of 0.004.

[0011] Furthermore, the first top dielectric substrate layer (14) is set to F4BM220 with a thickness of 1.52 mm, a relative permittivity of 2.2, and a tangent loss angle of 0.001; the second adhesive layer (16) is set to RO4450F with a thickness of 0.10 mm, a relative permittivity of 3.52, and a tangent loss angle of 0.004; and the first bottom dielectric substrate layer (17) is set to F4BTMS430 with a thickness of 0.25 mm, a relative permittivity of 4.3, and a tangent loss angle of 0.0019.

[0012] Furthermore, the second top dielectric substrate layer (23) is set to F4BM220 with a thickness of 1.52 mm, a relative permittivity of 2.2, and a tangent loss angle of 0.001; the third adhesive layer (25) is set to RO4450F with a thickness of 0.10 mm, a relative permittivity of 3.52, and a tangent loss angle of 0.004; the second bottom dielectric substrate layer (26) is set to F4BTMS430 with a thickness of 0.25 mm, a relative permittivity of 4.3, and a tangent loss angle of 0.0019.

[0013] Furthermore, achieving multi-beam radiation and reduced profile height requires simultaneous phase modulation of both the circularly polarized transmission array (1) and the circularly polarized reflection array (2), as detailed below:

[0014] The phase compensation required for the circularly polarized transmission array (1) is obtained by adding two parts: the first part is the phase generated by the distance from the equivalent feed located at the focal point to the different tunable phase transceiver units (4); the second part is the principal argument value after the linear superposition of the complex phases of the beams in each direction; therefore, the phase compensation formula for the mn-th tunable phase transceiver unit (4) is:

[0015]

[0016] Where k0 is the wave number in free space, x tmn and y tmn These are the x-axis distance and y-axis distance between the mn-th adjustable phase transceiver unit (4) and the center of the circularly polarized transmission array (1), respectively. F is the focal length of the circularly polarized transmission array (1), arg(Θ) represents the principal argument of the complex linear superposition phase Θ, and Δφ1 is a constant.

[0017] The circularly polarized reflective array (2) requires phase compensation to address the phase difference introduced by the reduced profile height while the focal length remains constant; therefore, the phase compensation formula for the mn-th tunable phase reflective unit (12) is:

[0018]

[0019] Where x rmn and yrmn φ1 and φ2 are respectively the x-axis distance and y-axis distance of the mnth adjustable phase reflection unit (12) from the center of the circularly polarized reflection array (2), H is the distance between the circularly polarized transmission array (1) and the circularly polarized reflection array (2), and Δφ2 is a constant.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The integrated low-profile multi-beam circularly polarized folded transmission array antenna proposed in this invention adopts a dual-phase compensation method, which reduces the profile height of the traditional single-feed multi-beam transmission array antenna to one-quarter of the focal length, and has the advantages of low profile and easy integration.

[0022] 2. The adjustable phase transceiver unit proposed in this invention adopts a rotating phase modulation method, which achieves a phase change of 0°-360° while maintaining a constant transmission amplitude, thus having the advantage of stable phase modulation performance.

[0023] 3. The adjustable phase reflection unit proposed in this invention has the ability to independently modulate the phase of the x and y components of the circularly polarized electromagnetic wave. Depending on the requirements, it can reflect the incident left-hand circularly polarized electromagnetic wave into a right-hand circularly polarized electromagnetic wave and perform phase modulation, or it can reflect the incident left-hand circularly polarized electromagnetic wave into a left-hand circularly polarized electromagnetic wave and perform phase modulation, thus having the advantage of flexibly controlling the electromagnetic wave.

[0024] 4. The planar integrated feed proposed in this invention adopts dual-port slot coupling feeding. Depending on the requirements, one port can be selected for feeding while the other port is connected to an external matching load to generate clockwise or counterclockwise rotating current, radiating right-hand circularly polarized electromagnetic waves or left-hand circularly polarized electromagnetic waves. It has the advantages of broadband, easy integration, and polarization agility.

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a cross-sectional view of the integrated low-profile multi-beam circularly polarized folded transmission array antenna of the present invention, wherein (a) is the front view of the antenna, (b) is the upper and lower surfaces of the circularly polarized transmission array, and (c) is the upper and lower surfaces of the circularly polarized reflection array.

[0027] Figure 2 This is a schematic diagram of the main unit structure of the present invention, wherein (a) is an adjustable phase transceiver unit, (b) is an adjustable phase reflector unit, and (c) is a planar integrated feed.

[0028] Figure 3The diagram shows the metal patch of the tunable phase transceiver unit of the present invention, wherein (a) is the upper metal patch layer and the lower metal patch layer, and (b) is the method for the tunable transceiver unit to achieve phase modulation.

[0029] Figure 4 This is a metal patch diagram of the adjustable phase reflection unit of the present invention.

[0030] Figure 5 This is a schematic diagram of the intermediate metal coupling ground layer and the bottom metal feed layer of the planar integrated feed source of the present invention.

[0031] Figure 6 The diagram shows the simulation performance of the adjustable phase transceiver unit of the present invention, where (a) represents the reflection performance and (b) represents the transmission performance.

[0032] Figure 7 This is a simulated reflection performance diagram of the adjustable phase reflection unit of the present invention.

[0033] Figure 8 The following are simulation performance diagrams of the planar integrated feed of the present invention, where (a) is the S-parameter and axial ratio curve, and (b) is the polar coordinate radiation pattern.

[0034] Figure 9 The diagrams show the phase modulation distribution of the circularly polarized transmission array and the circularly polarized reflection array of the present invention, wherein (a) is the phase modulation distribution that can be achieved by the circularly polarized transmission array, and (b) is the phase modulation distribution that can be achieved by the circularly polarized reflection array.

[0035] Figure 10 This is a simulated three-dimensional radiation pattern of the antenna of the present invention.

[0036] Figure 11 The radiation patterns of the antenna of the present invention at different frequencies in the Cartesian coordinate system are shown, where (a) is 9.5 GHz, (b) is 10.0 GHz, and (c) is 10.5 GHz.

[0037] Figure 12 This is a graph showing the axial ratio versus elevation angle of the antenna of the present invention at different frequencies. Detailed Implementation

[0038] 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, and not all embodiments. The components of the embodiments of the present invention described and represented herein can generally be arranged and designed in various different configurations.

[0039] The specific implementation methods provided by this invention are as follows:

[0040] Combination Figure 1 This example provides an integrated low-profile multi-beam circularly polarized folded transmission array antenna, which includes a circularly polarized transmission array (1), a circularly polarized reflection array (2), and a planar integrated feed (3); the circularly polarized transmission array (1) is placed directly above the circularly polarized reflection array (2) at a position H = 38.00 mm; the center of the circularly polarized reflection array (2) is hollowed out; the planar integrated feed (3) is embedded in the center of the circularly polarized reflection array (2). The circularly polarized transmission array (1) includes several periodically arranged tunable phase transceiver transmission units (4); the circularly polarized reflection array (2) includes several periodically arranged tunable phase reflection units (12); the circularly polarized transmission array (1) and the circularly polarized reflection array (2) are simultaneously phase-modulated, i.e., the dual-phase compensation method; under the conditions of multi-beam radiation and low profile, the circularly polarized transmission array (1) compensates for the path phase delay of the circularly polarized spherical electromagnetic wave and the principal value of the phase angle of the complex linear superposition phase of each radiation beam to generate multi-beam radiation; the circularly polarized reflection array (2) is used to compensate for the change in the path phase of the circularly polarized electromagnetic wave caused by the reduction in profile height, so as to cooperate with the phase-modulation compensation of the circularly polarized transmission array (1) to achieve the reduction in profile height.

[0041] Combination Figure 2 (a) and Figure 3The adjustable phase transceiver unit (4) includes, from top to bottom, an upper metal patch layer (5), an upper dielectric substrate layer (6), an intermediate metal ground layer (7), a first adhesive layer (8), a lower dielectric substrate layer (9), and a lower metal patch layer (10); the metal via (11) is cylindrical and located at the center of the adjustable phase transceiver unit (4), extending from the upper metal patch layer (5) to the lower metal patch layer (9), with a diameter of 0.40 mm; the lower metal patch layer (10) is polarized. Under matching conditions, the metal via (11) transmits the induced current generated by the lower metal patch layer (10) to the upper metal patch layer (5) to excite the upper metal patch layer (5) to radiate left-hand circularly polarized electromagnetic waves; the upper metal patch layer (5) is rectangular and etched with an asymmetric U-shaped slot, the length L1 and width L2 of the rectangular patch are 9.40 mm and 6.50 mm respectively, the length L4 of the left arm of the asymmetric U-shaped slot is 5.50 mm, the length L3 of the right arm is 2.60 mm, and the distance between the two arms is L5 = 3.00 mm. The width W1 of the groove is 0.50 mm; a circular gap is etched in the center of the intermediate metal layer (7) to isolate the upper metal patch layer (5) and the lower metal patch layer (10), and the diameter of the circular gap is 1.60 mm; the lower metal patch layer (10) is rectangular and etched with an asymmetric U-shaped gap, and its structural dimensions are the same as those of the upper metal patch layer (5), and it is used to receive right-hand circularly polarized electromagnetic waves and reflect left-hand circularly polarized electromagnetic waves, i.e., polarization matching and polarization mismatch; the upper dielectric substrate layer (6) and the lower dielectric substrate The plate layer (9) is made of F4BTM350 material, with a thickness of 1.52mm, a relative permittivity of 3.5, and a tangent loss angle of 0.0025; the first adhesive layer (8) is made of RO4450F material, with a thickness of 0.10mm, a relative permittivity of 3.52, and a tangent loss angle of 0.004; the adjustable phase transceiver unit (4) achieves a phase change of 0°-360° by rotating the upper metal patch layer (5) counterclockwise about the metal through hole (11) by ψ2=0°-360°.

[0042] Combination Figure 2 (b) and Figure 4The adjustable phase reflection unit (12) includes, from top to bottom, a top metal reflective patch layer (13), a first top dielectric substrate layer (14), an intermediate metal ground layer (15), a second adhesive layer (16), a first bottom dielectric substrate layer (17), and a bottom metal phase adjustment patch layer. The top metal reflective patch layer (13) is square with a side length W2 of 8.90 mm. A circular gap with a diameter of 1.10 mm is etched in the center of the intermediate metal ground layer (15). The bottom metal phase adjustment patch layer includes an x-axis phase adjustment delay line (18) and a y-axis phase adjustment delay line (19). The x-axis phase adjustment delay line (18) is rectangular and extends towards the positive half-axis with a length L. x The y-axis phase delay line (19) is rectangular and extends towards the negative half-axis, with a length of L. y The x-axis metal via (20) is cylindrical and connects the top metal reflective patch layer (13) and the x-axis phase-modulation delay line (18). It is used to transfer the x-component induced current generated by the top metal reflective patch layer (13) to the x-axis phase-modulation delay line (18) to achieve phase modulation of the x-component of the circularly polarized electromagnetic wave. The diameter of the x-axis metal via (20) is 0.70 mm. The y-axis metal via (21) is cylindrical and connects the top metal reflective patch layer (13) and the y-axis phase-modulation delay line (19). It is used to transfer the y-component induced current generated by the top metal reflective patch layer (13) to the y-axis phase-modulation delay line (19) to achieve phase modulation of the y-component of the circularly polarized electromagnetic wave. The diameter of the y-axis metal via (21) is 0.70 mm. The first top dielectric substrate layer (14) is made of F4BM220 material and has a thickness of 1.52 μm. m, relative permittivity is 2.2, tangent loss angle is 0.001; the first adhesive layer (8) is made of RO4450F material, has a thickness of 0.10mm, relative permittivity is 3.52, tangent loss angle is 0.004; the second adhesive layer (16) is made of RO4450F material, has a thickness of 0.10mm, relative permittivity is 3.52, tangent loss angle is 0.004; the first bottom dielectric substrate layer (17) is made of F4BTMS430 material, has a thickness of 0.25mm, relative permittivity is 4.3, tangent loss angle is 0.0019; the adjustable phase reflection unit (12) achieves a phase change of 0°-360° by simultaneously adjusting the lengths of the x-direction phase delay line (18) and the y-direction phase delay line (19) within the range of 0.50-6.50mm, and then lets L x =L y It can reflect incident circularly polarized electromagnetic waves into orthogonally polarized electromagnetic waves.

[0043] Combination Figure 2 (c) and Figure 5The planar integrated feed (3) has the same stacked structure as the adjustable phase reflection unit (12), including a top metal radiating patch layer (22), a second top dielectric substrate layer (23), an intermediate metal coupling ground layer (24), a third adhesive layer (25), a second bottom dielectric substrate layer (26), and a bottom metal feed layer (27) stacked sequentially from top to bottom; the top metal radiating patch layer (22) is circular with a diameter of 9.60 mm; the intermediate metal coupling ground layer (24) has a star-shaped slot etched in the center, which includes four rectangular slots with a length and width of 5.60 mm and 0.2 mm respectively; the bottom metal feed layer (27) is a ring microstrip line with a port 1 for external matching load and a port 2 for external radio frequency signal source at both ends; the parameters of the ring microstrip line are: L6 = 9.30 mm, L7 = 4.50 mm, L8 = 2.30 mm, W c =0.50mm, W f = 0.60mm; The planar integrated feed (3) excites the cross-shaped gap of the intermediate metal coupling ground layer (24) in a counterclockwise direction through the excitation port 2, radiating left-hand circularly polarized electromagnetic waves; The second top dielectric substrate layer (23) is made of F4BM220 with a thickness of 1.52mm, a relative permittivity of 2.2, and a tangent loss angle of 0.001; The third adhesive layer (25) is made of RO4450F with a thickness of 0.10mm, a relative permittivity of 3.52, and a tangent loss angle of 0.004; The second bottom dielectric substrate layer (26) is made of F4BTMS430 with a thickness of 0.25mm, a relative permittivity of 4.3, and a tangent loss angle of 0.0019;

[0044] The periods of the tunable phase transceiver unit (4) and the tunable phase reflector unit (12) are both P. t = 13.00mm; The side length of the planar integrated feed is L9 = 26.00mm, so that the size of the hollow area in the center of the circularly polarized reflective array (2) can be set to 2×2 adjustable phase reflective units (12); To achieve multi-beam radiation and reduce the profile height, the circularly polarized transmission array (1) and the circularly polarized reflective array (2) need to be phase-tuned at the same time, as follows:

[0045] The phase compensation required for the circularly polarized transmission array (1) is obtained by adding two parts: the first part is the phase generated by the distance from the equivalent feed located at the focal point to the different tunable phase transceiver units (4); the second part is the principal argument value after the linear superposition of the complex phases of the beams in each direction; therefore, the phase compensation formula for the mn-th tunable phase transceiver unit (4) is:

[0046]

[0047] Where k0 is the wave number in free space, x tmn and y tmn These are the x-axis distance and y-axis distance of the mn-th adjustable phase transceiver unit (4) from the center of the circularly polarized transmission array (1), respectively. F is the focal length of the circularly polarized transmission array (1), arg(Θ) represents the principal argument of the complex linear superposition phase Θ, and Δφ1 is a constant. The circularly polarized reflection array (2) needs to adjust the phase to compensate for the phase difference introduced by the decrease in profile height while the focal length remains unchanged. Therefore, the phase compensation formula for the mn-th adjustable phase reflection unit (12) is:

[0048]

[0049] Where x rmn and y rmn φ1 and φ2 are respectively the x-axis distance and y-axis distance of the mnth adjustable phase reflection unit (12) from the center of the circularly polarized reflection array (2), H is the distance between the circularly polarized transmission array (1) and the circularly polarized reflection array (2), and Δφ2 is a constant.

[0050] Figure 6 (a) and Figure 6 (b) Simulated reflection and transmission performance curves of the tunable phase transceiver unit (4) are presented respectively. It can be seen that in the frequency range of 9.5 GHz to 10.5 GHz, the amplitude of the reflection coefficient of the left-hand circularly polarized wave reflected as a left-hand circularly polarized wave and the amplitude of the transmission coefficient of the right-hand circularly polarized wave transmitted as a left-hand circularly polarized wave are both greater than −1.0 dB. At the same time, the transmission phase change covers 360°, while the reflection phase does not have a phase change.

[0051] Figure 7 The simulated reflection performance curves of the tunable phase reflection unit (12) are given. It can be seen that a 360° phase change is generated in the frequency range of 9.0 GHz to 11.0 GHz, and the reflection amplitude of reflecting left-hand circularly polarized electromagnetic waves into right-hand circularly polarized electromagnetic waves is greater than −1.5 dB.

[0052] Figure 8 (a) The simulated S-parameters and axial ratio curves of the planar integrated feed (3) are given. It can be seen that the reflection coefficient amplitude and axial ratio of port 2 are less than -10.0dB and 2.0dB, respectively, in the frequency range of 9.0GHz to 12.0GHz. Figure 8 (b) The polar coordinate radiation pattern of the planar integrated feed (3) is given. It can be seen that at the frequency of 10.0 GHz, the maximum gain of the left-hand circularly polarized wave is 5.7 dBi, the 3 dB beamwidth is 74.8°, the sidelobe level is −34.7 dB, and the cross-polarization level is −20.5 dB.

[0053] Figure 9 (a) and Figure 9 (b) The phase distribution diagrams of the circularly polarized transmission array (1) and the circularly polarized reflection array (2) required to realize four-beam radiation are given respectively. In this embodiment, the number of elements of the circularly polarized transmission array (1) and the circularly polarized reflection array (2) is 18×18.

[0054] Figure 10 A three-dimensional simulation radiation pattern of the antenna in the embodiment is given, which achieves good four-beam radiation.

[0055] Figure 11 Two-dimensional radiation patterns of the antenna at 9.5 GHz, 10.0 GHz, and 10.5 GHz are presented. It can be seen that focused beams are simultaneously achieved in the directions of (44°, 0°), (40°, 90°), (40°, 180°), and (42°, 270°), with corresponding gains of 12.4 dBi, 11.0 dBi, 12.4 dBi, and 11.5 dBi, respectively. The sidelobe level at 10.0 GHz is less than −10.0 dB, and the cross-polarization level in the main beam direction is less than −20.0 dB.

[0056] Figure 12 The axial ratio versus elevation angle θ curves of the example antenna at 9.5 GHz, 10.0 GHz and 10.5 GHz are given. It can be seen that the axial ratio of the three frequency points in the main beam direction is less than 3.0 dB in both the xoz and yoz planes, achieving good circular polarization performance.

[0057] As can be seen from the above, the present invention has the characteristics of low profile, simultaneous four-beam radiation, and easy integration.

[0058] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An integrated, low-profile, multi-beam circularly polarized folded transmission array antenna, characterized in that, The antenna includes a circularly polarized transmission array (1), a circularly polarized reflection array (2), and a planar integrated feed (3); the circularly polarized transmission array (1) is placed directly above the circularly polarized reflection array (2); the circularly polarized reflection array (2) has a hollow center; and the planar integrated feed (3) is embedded in the center of the circularly polarized reflection array (2). The circularly polarized transmission array (1) includes several periodically arranged tunable phase transceiver transmission units (4); the circularly polarized reflection array (2) includes several periodically arranged tunable phase reflection units (12); the circularly polarized transmission array (1) and the circularly polarized reflection array (2) are simultaneously phase-modulated, i.e., the dual-phase compensation method; under the conditions of multi-beam radiation and low profile, the circularly polarized transmission array (1) compensates for the path phase delay of the circularly polarized spherical electromagnetic wave and the principal value of the phase angle of the complex linear superposition phase of each radiation beam to generate multi-beam radiation; the circularly polarized reflection array (2) is used to compensate for the change in the path phase of the circularly polarized electromagnetic wave caused by the reduction in profile height, so as to cooperate with the phase-modulation compensation of the circularly polarized transmission array (1) to achieve the reduction in profile height.

2. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 1, characterized in that, The adjustable phase transceiver unit (4) includes an upper metal patch layer (5), an upper dielectric substrate layer (6), an intermediate metal ground layer (7), a first adhesive layer (8), a lower dielectric substrate layer (9), and a lower metal patch layer (10) stacked sequentially from top to bottom. A cylindrical metal via (11) is located at the center of the adjustable phase transceiver unit (4) and extends from the upper metal patch layer (5) to the lower metal patch layer (9). Under polarization matching conditions of the lower metal patch layer (10), the metal via (11) transmits the induced current generated by the lower metal patch layer (10) to the upper metal patch layer (5) to excite the upper metal patch layer. The sheet (5) radiates left-hand circularly polarized electromagnetic waves; the upper metal patch layer (5) is rectangular and etched with asymmetric U-shaped slots; the middle metal ground layer (7) has a circular slot etched in the center to isolate the upper metal patch layer (5) and the lower metal patch layer (10); the lower metal patch layer (10) is rectangular and etched with asymmetric U-shaped slots to receive right-hand circularly polarized electromagnetic waves and reflect left-hand circularly polarized electromagnetic waves, i.e., polarization matching and polarization mismatch; the adjustable phase transceiver unit (4) achieves a phase change of 0°-360° by rotating the upper metal patch layer (5) counterclockwise about the metal through hole (11) by 0°-360°.

3. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 1, characterized in that, The adjustable phase reflection unit (12) includes a top metal reflective patch layer (13), a first top dielectric substrate layer (14), an intermediate metal ground layer (15), a second adhesive layer (16), a first bottom dielectric substrate layer (17), and a bottom metal phase adjustment patch layer, which are stacked sequentially from top to bottom. The top metal reflective patch layer (13) is square. A circular slit is etched in the center of the intermediate metal ground layer (15). The bottom metal phase adjustment patch layer includes an x-axis phase adjustment delay line (18) and a y-axis phase adjustment delay line (19). The x-axis phase adjustment delay line (18) is rectangular and extends towards the positive half-axis. The y-axis phase adjustment delay line (19) is rectangular and extends towards the negative half-axis. The x-axis metal via (20) is cylindrical and connects to the top. The top metal reflective patch layer (13) and the x-direction phase-modulation delay line (18) are used to transfer the x-component induced current generated by the top metal reflective patch layer (13) to the x-direction phase-modulation delay line (18) to achieve phase modulation of the x-component of the circularly polarized electromagnetic wave; the y-direction metal via (21) is cylindrical and connects the top metal reflective patch layer (13) and the y-direction phase-modulation delay line (19) to transfer the y-component induced current generated by the top metal reflective patch layer (13) to the y-direction phase-modulation delay line (19) to achieve phase modulation of the y-component of the circularly polarized electromagnetic wave; the adjustable phase reflection unit (12) achieves a phase change of 0°-360° by simultaneously adjusting the lengths of the x-direction phase-modulation delay line (18) and the y-direction phase-modulation delay line (19).

4. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 1, characterized in that, The planar integrated feed (3) has the same stacked structure as the tunable phase reflection unit (12), including a top metal radiating patch layer (22), a second top dielectric substrate layer (23), an intermediate metal coupling ground layer (24), a third adhesive layer (25), a second bottom dielectric substrate layer (26), and a bottom metal feed layer (27) stacked sequentially from top to bottom; the top metal radiating patch layer (22) is circular; the intermediate metal coupling ground layer (24) has a star-shaped slot etched in the center; the bottom metal feed layer (27) is a ring microstrip line with a port 1 for external matching load and a port 2 for external radio frequency signal source at both ends; the planar integrated feed (3) excites the star-shaped slot of the intermediate metal coupling ground layer (24) in a counterclockwise direction through the excitation port 2, radiating left-hand circularly polarized electromagnetic waves.

5. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 2, characterized in that, The upper dielectric substrate layer (6) and the lower dielectric substrate layer (9) can be set to F4BTM350, the thickness can be set to 1.52mm, the relative permittivity is 3.5, and the tangent loss angle is 0.0025; the first adhesive layer (8) can be set to RO4450F, the thickness can be set to 0.10mm, the relative permittivity is 3.52, and the tangent loss angle is 0.

004.

6. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 3, characterized in that, The first top dielectric substrate layer (14) can be set to F4BM220, the thickness can be set to 1.52mm, the relative permittivity is 2.2, and the tangent loss angle is 0.001; the second adhesive layer (16) can be set to RO4450F, the thickness can be set to 0.10mm, the relative permittivity is 3.52, and the tangent loss angle is 0.004; the first bottom dielectric substrate layer (17) can be set to F4BTMS430, the thickness can be set to 0.25mm, the relative permittivity is 4.3, and the tangent loss angle is 0.0019.

7. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 4, characterized in that, The second top dielectric substrate layer (23) can be set to F4BM220, the thickness can be set to 1.52mm, the relative permittivity is 2.2, and the tangent loss angle is 0.001; the third adhesive layer (25) can be set to RO4450F, the thickness can be set to 0.10mm, the relative permittivity is 3.52, and the tangent loss angle is 0.004; the second bottom dielectric substrate layer (26) can be set to F4BTMS430, the thickness can be set to 0.25mm, the relative permittivity is 4.3, and the tangent loss angle is 0.0019.

8. The integrated low-profile multi-beam circularly polarized folded transmission array antenna according to claim 1, characterized in that, To achieve multi-beam radiation and reduced profile height, the circularly polarized transmission array (1) and the circularly polarized reflection array (2) need to be phase-tuned simultaneously, as follows: The phase compensation required for the circularly polarized transmission array (1) is obtained by adding two parts: the first part is the phase generated by the distance from the equivalent feed located at the focal point to the different tunable phase transceiver units (4); the second part is the principal argument value after the linear superposition of the complex phases of the beams in each direction; therefore, the phase compensation formula for the mn-th tunable phase transceiver unit (4) is:

9. Where k0 is the wave number in free space, x tmn and y tmn These are the x-axis distance and y-axis distance between the mn-th adjustable phase transceiver unit (4) and the center of the circularly polarized transmission array (1), respectively. F is the focal length of the circularly polarized transmission array (1), arg(Θ) represents the principal argument of the complex linear superposition phase Θ, and Δφ1 is a constant. The circularly polarized reflective array (2) requires phase compensation to address the phase difference introduced by the reduced profile height while the focal length remains constant; therefore, the phase compensation formula for the mn-th tunable phase reflective unit (12) is:

10. Where x rmn and y rmn φ1 and φ2 are respectively the x-axis distance and y-axis distance of the mnth adjustable phase reflection unit (12) from the center of the circularly polarized reflection array (2), H is the distance between the circularly polarized transmission array (1) and the circularly polarized reflection array (2), and Δφ2 is a constant.

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