A compact folded transmissive array antenna with very low profile

Abstract

The utility model discloses a compact folding transmission array antenna with very low profile, including plane feed source, transmission array and reflection array three part composition. Through the design of polarization twist transmission unit, polarization twist reflection unit, the utility model not only carries out phase compensation to transmission array, still introduced additional phase compensation on reflection array, and double phase compensation makes antenna profile reduce to 1 / 6 of traditional transmission array. The antenna adopts plane feed source feed, compares with the folding transmission array of horn loudspeaker feed, not only reduces the profile of feed source, still realized array and feed source integration design, compared with the folding 1 / 3 transmission array of using more in recent years, profile height can reduce to 1 / 6, and this design realizes very low profile and feed source and array integration simultaneously still has good caliber efficiency and broadband characteristic.

Description

Technical Field

[0001] This invention belongs to the field of transmission array antenna technology, and in particular to a compact folded transmission array antenna with an extremely low profile. Background Technology

[0002] Transmissive array antennas, as a typical high-gain antenna, have gained widespread attention and application in wireless communication systems in recent years due to their relatively simple structure, low manufacturing cost, and ease of integration with other circuits and systems. Compared with traditional reflective arrays or parabolic antennas, transmissive arrays not only reduce weight while maintaining high efficiency but also possess stronger advantages in planarity and modularity, thus showing great application potential in modern communications, satellite navigation, radar imaging, and the Internet of Things. However, transmissive array antennas also have certain limitations. For example, their operating bandwidth is usually narrow, making it difficult to meet the needs of multi-band or ultra-wideband communication; at the same time, their overall structural height is relatively large, which limits their application in some scenarios where low profile and lightweight requirements are high. With the continuous evolution of communication technologies, especially the development of 5G, 6G, and next-generation satellite communications, higher performance requirements have been placed on antennas. Miniaturization, low profile, and high integration have become core trends in antenna design. To overcome the shortcomings of traditional transmissive array antennas, researchers are actively exploring the introduction of metasurfaces and artificial electromagnetic materials, as well as new methods of phase modulation and broadband design, to achieve a comprehensive performance improvement in broadband, lightweight, and compactness while maintaining high gain.

[0003] In recent years, scholars at home and abroad have proposed many transmissive array antennas. In 2015, Abdelrahman AH et al. (Abdelrahman AH, Nayeri P, Elsherbeni AZ, et al. Bandwidth Improvement Methods of Transmitarray Antennas[J]. IEEE Transactions on Antennas and Propagation, 2015, 63(7):2946-2954.) proposed a four-layer transmissive array antenna based on two-sided ring elements. However, the design of multi-layer structures generally suffers from problems such as high profile, difficulty in integration, and complex installation. In 2016, An Wenxing et al. (An W, Xu S, Yang F, et al. A Double-Layer Transmitarray Antenna Using Malta Crosses With Vias[J]. IEEE Transactions on Antennas and Propagation,2016, 64(3):1120-1125.) proposed a transmission array antenna based on a single-layer dielectric substrate. By adopting Malta cross patches and metallized via structures, the profile height was reduced to 0.105λ. However, metal vias were added to the transmission elements, increasing the structural complexity. In 2017, Fan C, Che W, Yang W, et al. A NovelPRAMC-Based Ultralow-Profile Transmitarray Antenna by Using Ray Tracing Principle[J]. IEEE Transactions on Antennas and Propagation, 2017, 65(4):1779-1787. proposed a novel low-profile folded transmission array based on the ray tracing principle. It uses a broadband polarized torsional reflector based on an artificial magnetic conductor to change the polarization direction of the incident wave, thereby reducing the antenna profile height to 1 / 3 of the focal length.In 2022, Li Tangjing et al. (Li TJ, Wang GM, Liang JG, et al. A Method for Transmitarray Antenna Profile Reduction Based on Ray Tracing Principle[J].IEEE Antennas and Wireless Propagation Letters, 2022, 21(12):2542-2546.) proposed using a dual-phase compensation method to further reduce the profile height to 1 / 4 of the focal length without changing the focal diameter ratio of the transmit array antenna. Although the above research has effectively reduced the profile height of the transmit array antenna, taking the paper "A Method for Transmitarray Antenna Profile Reduction Based on Ray Tracing Principle" as an example, while reducing the profile height, its maximum aperture efficiency also decreased (28%).

[0004] Therefore, starting from the three factors affecting the antenna profile—unit thickness, feed thickness, and distance between the feed and the transmission array—designing and researching a folded 1 / 6 transmission array antenna composed of antenna units made of a single-layer dielectric substrate without metal vias and a planar feed has good novelty and practical significance. Utility Model Content

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a single-layer dielectric substrate transmission array and an integrated planar feed reflection array that do not use metal through-holes, thereby reducing the antenna profile to 1 / 6 of that of a traditional transmission array while achieving good aperture efficiency and bandwidth.

[0006] The technical solution to achieve the purpose of this utility model is as follows: a compact folded transmission array antenna with an extremely low profile, the antenna comprising: a planar feed, a transmission array, and a reflection array; the planar feed is embedded in the middle of the reflection array, and the transmission array is placed above the reflection array; the planar feed emits an x-polarized wave, which is totally reflected when it reaches below the transmission array; when the reflected wave reaches the surface of the reflection array, the reflection array introduces additional phase compensation and reflects and twists the incident x-polarized wave into a y-polarized wave, reducing the array profile height; at the same time, the transmission array transmits the y-polarized wave and performs phase compensation on the y-polarized wave, forming a transmission focused beam with polarization twisted into x-polarization;

[0007] The transmission array includes several periodically arranged double-horn-shaped polarized torsional transmission units. Each double-horn-shaped polarized torsional transmission unit includes an upper metal patch, a first dielectric substrate, and a lower metal patch arranged sequentially from top to bottom. The upper and lower metal patches are both symmetrical double-horn shapes, forming an "x" structure. The upper or lower metal patch includes a rectangular metal patch, and a first horn-shaped metal patch and a second horn-shaped metal patch located at both ends of the rectangular metal patch along its length. The two corners of the first horn-shaped metal patch and the two corners of the second horn-shaped metal patch are symmetrical about the central axis of the rectangular metal patch along its length, and the first and second horn-shaped metal patches are symmetrical about the central axis of the rectangular metal patch along its width.

[0008] Furthermore, the projections of the upper metal patch and the lower metal patch are at a 45° angle.

[0009] Furthermore, the opening angle α of the double horn-shaped metal patch is adjustable. By adjusting the opening angle α, the phase compensation required for the transmission array can be obtained. The opening angle α is the angle formed by the extension line of the end edge of the first horn-shaped metal patch or the second horn-shaped metal patch and the extension line of the perpendicular line to the central axis of the rectangular metal patch along its length.

[0010] Furthermore, by performing a horizontal mirroring operation on the polarized torsional reflector, a continuous phase change of 0°-360° for the transmission array is achieved.

[0011] Furthermore, the reflective array includes several periodically arranged torsional reflective units, each torsional reflective unit including a metal patch, a second dielectric substrate, and a first metal ground plane arranged sequentially from top to bottom; the metal patch includes: an L-shaped metal patch, an isosceles right-angled triangular metal patch inscribed at the right angle of the L-shaped metal patch, and a first rectangular metal patch and a second rectangular metal patch respectively disposed at the ends of the two sides of the L-shaped metal patch and perpendicular to the two sides.

[0012] Furthermore, the length L of the first rectangular metal patch and the second rectangular metal patch is adjustable, and the phase compensation required by the reflective array can be obtained by adjusting L.

[0013] Furthermore, the widths of the first rectangular metal patch and the second rectangular metal patch are the same as the width of the L-shaped metal patch, and the lengths and widths of the two sides of the L-shaped metal patch are the same.

[0014] Furthermore, the planar feed source includes a second metal floor and a V-groove metal patch disposed above the second metal floor, with a second dielectric substrate disposed between the two; the V-groove metal patch is a metal patch with a V-groove cut out in the center, and the V-groove is a V-groove structure with the bottom corner of the "V" cut off in the horizontal direction; a coordinate system o-xyz is established with the horizontal left and right directions as the x-axis and the vertical direction as the z-axis, the bottom edge of the V-groove is set along the x-axis direction, the groove opening is symmetrical about the y-axis, and the groove opening direction is along the positive y-axis direction.

[0015] Furthermore, the transmission array and the reflection array have the same shape and structure, and their central projections overlap.

[0016] Furthermore, the unit spacing of the double horn-shaped polarized torsional transmission unit is P=0.333λ, where λ is the free space wavelength corresponding to 10GHz.

[0017] Compared with the prior art, the significant advantages of this utility model are:

[0018] (1) The transmission unit proposed in this utility model adopts a single-layer dielectric substrate and does not use metal through holes. Compared with the multi-layer stacked unit structure, it not only simplifies the structure, but also greatly reduces the cost.

[0019] (2) The transmission unit and reflection unit designed in this utility model can achieve continuous phase change from 0 to 360° while having a low unit profile.

[0020] (3) The present invention uses a planar feed source for power supply, which has advantages such as small size and easy integration compared with the cone horn feed source.

[0021] (4) The antenna proposed in this utility model can reduce the antenna profile to 1 / 6, which is the lowest profile height in the current technology.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the working principle of a compact folded transmission array antenna with an extremely low profile in one embodiment.

[0024] Figure 2 This is a schematic diagram of a compact folded transmission array antenna with an extremely low profile in one embodiment, wherein... Figure 2 Image (a) is a three-dimensional schematic diagram of a folded transmission array antenna. Figure 2 (b) in the image is a side view of the folded transmission array antenna. Figure 2 (c) in the diagram is the main schematic diagram of the planar feed.

[0025] Figure 3This is a schematic diagram of the transmission element of a compact folded transmission array antenna with an extremely low profile in one embodiment.

[0026] Figure 4 This is a schematic diagram of two states of the transmission element of a compact folded transmission array antenna with an extremely low profile in one embodiment, wherein... Figure 4 In this context, (a) represents state A. Figure 4 (b) in the equation represents state B.

[0027] Figure 5 This is a schematic diagram of the torsional reflection element of a compact folded transmission array antenna with an extremely low profile in one embodiment, wherein... Figure 5 (a) is the main diagram of the torsional reflective unit. Figure 5 (b) is a side view of the torsional reflector unit.

[0028] Figure 6 This is a schematic diagram of a planar feed for a compact folded transmission array antenna with an extremely low profile in one embodiment, wherein... Figure 6 (a) is the main diagram. Figure 6 (b) is a side view.

[0029] Figure 7 This is a graph showing the transmission amplitude and phase of a transmission element of a compact folded transmission array antenna with an extremely low profile in one embodiment, under two different states before and after design frequency mirroring.

[0030] Figure 8 The transmission amplitude and phase curves of a compact folded transmission array antenna with an extremely low profile in one embodiment are shown in state A, with the center frequency at 10 GHz, for changing the incident angle.

[0031] Figure 9 The diagram shows the reflection amplitude and phase curves of a compact folded transmission array antenna with an extremely low profile in one embodiment, under two different states before and after the design frequency mirroring.

[0032] Figure 10 The following is an example of a compact folded transmission array antenna reflection element with an extremely low profile in one embodiment, at a center frequency of 10 GHz, showing the reflection amplitude and phase curves of the element with varying incident angles, taking state A as an example.

[0033] Figure 11 The image shows the simulated E-plane and H-plane radiation patterns of a compact folded transmission array antenna with an extremely low profile operating at a center frequency of 10 GHz in one embodiment.

[0034] Figure 12This is a graph showing the simulated antenna gain and aperture efficiency as a function of frequency for a compact folded transmission array antenna with an extremely low profile in the range of 8 GHz to 12 GHz, as described in one embodiment. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0037] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0038] In one embodiment, combined Figures 1 to 5 A compact folded transmission array antenna with an extremely low profile is provided. The antenna includes: a planar feed 1, a transmission array 2, and a reflective array 3; the planar feed 1 is embedded in the middle of the reflective array 3, and the transmission array 2 is placed above the reflective array 3. Figure 1The planar feed 1 emits an x-polarized wave (ray 1). When the x-polarized wave reaches below the transmission array 2, it is totally reflected (ray 2). When the reflected wave reaches the surface of the reflection array 3, the reflection array 3 introduces additional phase compensation and reflects and twists the incident x-polarized wave into a y-polarized wave, reducing the array profile height (to 1 / 6 of that of a conventional empty feed array). At this time, the reflected y-polarized wave no longer exits along the direction of the connection line with the equivalent feed, but exits along the direction of the connection line with the focal point (ray 3). When the wave reaches the lower surface of the transmission array again, the transmission array 2 transmits the y-polarized wave and performs phase compensation on the y-polarized wave, forming a transmission focused beam (ray 4) that is twisted into x-polarized and then transmitted out. Therefore, the height between the transmission array and the reflection array can be reduced to 1 / 6 of the original focal length, realizing an extremely low profile design.

[0039] Furthermore, in one embodiment, combined with Figure 3 The transmission array 2 includes several periodically arranged double-horn-shaped polarized torsional transmission units 4. Each double-horn-shaped polarized torsional transmission unit 4 includes an upper metal patch 6, a first dielectric substrate 7, and a lower metal patch 8 arranged sequentially from top to bottom. The upper metal patch 6 and the lower metal patch 8 are both symmetrical double-horn shapes, forming an "x" structure. The upper metal patch 6 or the lower metal patch 8 includes a rectangular metal patch, and a first horn-shaped metal patch and a second horn-shaped metal patch located at both ends of the rectangular metal patch along the length direction of the rectangular metal patch. The two corners of the first horn-shaped metal patch and the two corners of the second horn-shaped metal patch are symmetrical about the central axis of the rectangular metal patch along the length direction, and the first horn-shaped metal patch and the second horn-shaped metal patch are symmetrical about the central axis of the rectangular metal patch along the width direction.

[0040] Here, periodic arrangement uses, but is not limited to, rectangular arrays, circular arrays, etc.

[0041] Preferably, in some embodiments, the projections of the upper metal patch 6 and the lower metal patch 8 form a 45° angle. For example, the long side of the rectangular metal patch in the upper metal patch is rotated counterclockwise by β1 = 22.5° along the vertical line, and the long side of the rectangular metal patch in the lower metal patch is rotated counterclockwise by β2 = 67.5° along the vertical line.

[0042] Preferably, in some embodiments, the opening angle α of the double horns is adjustable. By adjusting the opening angle α, the phase compensation required for the transmission array 2 can be obtained. The opening angle α is the angle formed by the extension of the edge of the end of the first or second horn-shaped metal patch and the extension of the perpendicular line to the central axis of the rectangular metal patch along its length. Here, the adjustment of the opening angle can be achieved by changing the structural parameters of the double horns.

[0043] Preferably, in some embodiments, the polarization torsion reflection unit 5 is horizontally mirrored, such as... Figure 4 As shown, this enables continuous phase change of the transmission array over 360°.

[0044] Furthermore, in one embodiment, combined with Figure 5 The reflective array 3 includes several periodically arranged torsional reflective units 5. Each torsional reflective unit 5 includes a metal patch 9, a second dielectric substrate 10, and a first metal ground plate 11 arranged sequentially from top to bottom. The metal patch 9 includes an L-shaped metal patch, an isosceles right-angled triangular metal patch inscribed at the right angle of the L-shaped metal patch, and a first rectangular metal patch and a second rectangular metal patch respectively disposed at the ends of the two sides of the L-shaped metal patch and perpendicular to the two sides.

[0045] Preferably, in some embodiments, the length L of the first rectangular metal patch and the second rectangular metal patch is adjustable, and the phase compensation required by the reflective array 3 is obtained by adjusting L. Here, the adjustment of the length L is achieved by changing the size parameters of the metal patch.

[0046] Preferably, in some embodiments, the widths of the first rectangular metal patch and the second rectangular metal patch are the same as the width of the L-shaped metal patch, and the lengths and widths of the two sides of the L-shaped metal patch are the same.

[0047] Preferably, in some embodiments, one end of the first rectangular metal patch and the second rectangular metal patch completely overlap with the ends of the two sides of the L-shaped metal patch.

[0048] Furthermore, in one embodiment, combined with Figure 6 The planar feed 1 includes a second metal floor 14 and a V-groove metal patch 12 disposed above the second metal floor 14, with a second dielectric substrate 13 disposed between the two; the V-groove metal patch 12 is a metal patch with a V-groove cut in the center, and the V-groove is a V-groove structure with the bottom corner of the "V" cut off in the horizontal direction; a coordinate system o-xyz is established with the horizontal left and right direction as the x-axis and the vertical direction as the z-axis, the bottom edge of the V-groove is set along the x-axis direction, the groove opening is symmetrical about the y-axis, and the groove opening direction is along the positive y-axis direction.

[0049] Preferably, in some embodiments, the second metal floor 14, the second dielectric substrate 13, and the V-groove metal patch 12 are all rectangular structures, and the adjacent sides of the rectangular structures are respectively arranged along the x-axis and y-axis directions.

[0050] Preferably, in some embodiments, the transmission array 2 and the reflection array 3 have the same shape and structure, and their center projections overlap.

[0051] Preferably, in some embodiments, both the transmission array 2 and the reflection array 3 are circular arrays.

[0052] Preferably, in some embodiments, the unit spacing of the double horn-shaped polarized torsional transmission unit 4 is P=0.333λ, where λ is the free space wavelength corresponding to 10 GHz.

[0053] As a specific example, in one embodiment, the present invention will be further verified and explained.

[0054] In this embodiment, the transmission array 2 is composed of 556 double-horn-shaped polarized torsional transmission units 4 arranged periodically; the reflection array 3 is composed of 348 periodically arranged polarized torsional reflection units 5. In order to facilitate fixing and installation, the transmission array 2 and the reflection array 3 are extended into a circular array with a diameter of 280 mm along the edge. The vertical distance between the transmission array 2 and the reflection array 3 is 28 mm.

[0055] In this embodiment, the unit spacing of the dual horn-shaped polarized torsional transmission unit 4 is P1=10 mm, i.e. 0.333λ, where λ is the free space wavelength corresponding to 10 GHz. The width of the rectangular metal patch is L2=2.6 mm, the length of the rectangular metal patch is L1=4 mm, the width of the first horn-shaped metal patch or the second horn-shaped metal patch is w=1.6 mm, the inner diameter is R=0.7 mm, and the thickness of the first dielectric substrate 7 is H1=2.5 mm, i.e. 0.083λ. Compared with other working transmission units, this transmission unit is a single-layer structure and does not require the use of complex metal through holes, resulting in a lower profile.

[0056] In this embodiment, the unit spacing of the polarization torsional reflection unit 5 is P2=11 mm, or 0.367λ, where λ is the free space wavelength corresponding to 10 GHz. The length of the metal patch along the two sides of the L-shaped metal patch is D=7.8 mm. The distance from the side of the L-shaped metal patch to the side of the adjacent isosceles right-angled triangular metal patch is W1=1.8 mm. The side length of the isosceles right-angled triangular metal patch is 5.3 mm. The width of the first rectangular metal patch and the second rectangular metal patch is W2=1 mm. The thickness of the second dielectric substrate 10 is H2=2 mm, or 0.067λ. Since an integrated design is required, this thickness is consistent with the thickness of the planar feed dielectric substrate.

[0057] In this embodiment, the planar feed has a gain of 8.1 dBi at a center frequency of 10 GHz and a good reflection coefficient within the operating frequency band, which can meet the feed requirements of the antenna.

[0058] In this embodiment, the second dielectric substrate 13 in the planar feed has a length a1 = 32 mm, a width b1 = 13 mm, a height H3 = 2 mm, a length a2 = 16 mm, and a width b2 = 8 mm. The feed uses SMA feeding through the ground plane and the dielectric.

[0059] Depend on Figure 4 It can be seen that the double horn-shaped polarized torsional transmission unit 4 can form two different states by simultaneously mirroring the upper metal patch 6 and the lower metal patch 8 vertically.

[0060] Depend on Figure 7 It can be seen that when the size of the double horn-shaped polarized torsional transmission unit 4 is kept consistent, the transmission amplitudes in the two states are equal and the phase difference is 180°. When the opening angle α varies from 100° to 173°, the transmission amplitude is greater than -2 dB in all cases, and a continuous phase change of 360° is achieved. This indicates that the double horn-shaped polarized torsional transmission unit 4 has good performance.

[0061] Depend on Figure 8 It can be seen that the transmission amplitude of the double horn-shaped polarized torsional transmission unit 4 at 10 GHz is basically above -2.5 dB under different sizes and different incident angles, which indicates that the unit is less affected by the change of incident angle.

[0062] Depend on Figure 9 It can be seen that the polarization torsion reflection unit 5 can form two different states by vertically mirroring the metal patch 9. When the size of the polarization torsion reflection unit 5 is kept constant, the reflection amplitude of the two states is equal and the phase difference is 180°. The length L of the first rectangular metal patch and the second rectangular metal patch varies from 0.2 mm to 4.9 mm. The reflection amplitude of both is greater than -1 dB and a continuous phase change of 360° is achieved. This shows that the polarization torsion reflection unit 5 has good performance.

[0063] Depend on Figure 10 It can be seen that at 10 GHz, the reflection amplitude of the polarized torsional reflector 5 is basically above -1.5 dB under different sizes and different incident angles, which indicates that the unit is less affected by the change of incident angle.

[0064] Depend on Figure 11 It can be seen that the compact folded transmission array antenna with extremely low profile has good simulated radiation pattern performance in the E-plane and H-plane at 10 GHz.

[0065] Depend on Figure 12The simulated gain and aperture efficiency performance are good. The maximum aperture efficiency, at 33.4%, occurs at 9.4 GHz. The 3-dB gain bandwidth is 30%, ranging from 8.8 GHz to 11.8 GHz.

[0066] In summary, the compact folded transmission array antenna with an extremely low profile proposed in this invention further reduces the profile to 1 / 6 of the focal length by introducing phase compensation on the reflective array. The use of a planar feed helps reduce the overall size of the antenna structure and facilitates integrated design. This antenna can simultaneously achieve a wide operating bandwidth, high aperture efficiency, and low profile.

[0067] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model without departing from its spirit and scope should be included within the protection scope of this utility model.

Claims

1. A compact folded transmission array antenna with an extremely low profile, the antenna comprising: Planar feed (1), transmission array (2) and reflection array (3); the planar feed (1) is embedded in the middle of the reflection array (3), and the transmission array (2) is placed above the reflection array (3); the planar feed (1) emits an x-polarized wave, which is totally reflected when it reaches below the transmission array (2), and when the reflected wave reaches the surface of the reflection array (3), the reflection array (3) introduces additional phase compensation and reflects and twists the incident x-polarized wave into a y-polarized wave, reducing the array profile height. At the same time, the transmission array (2) transmits the y-polarized wave and performs phase compensation on the y-polarized wave, forming a transmission focusing beam that is polarized and twisted into x-polarized. The transmission array (2) includes several periodically arranged double horn-shaped polarized torsional transmission units (4). Each double horn-shaped polarized torsional transmission unit (4) includes an upper metal patch (6), a first dielectric substrate (7), and a lower metal patch (8) arranged sequentially from top to bottom. The upper metal patch (6) and the lower metal patch (8) are both symmetrical double horn shapes, forming an "x" structure. The upper metal patch (6) or the lower metal patch (8) includes a rectangular metal patch, and a first horn-shaped metal patch and a second horn-shaped metal patch located at both ends of the rectangular metal patch along the length direction of the rectangular metal patch. The two corners of the first horn-shaped metal patch and the two corners of the second horn-shaped metal patch are symmetrical about the central axis of the length direction of the rectangular metal patch, and the first horn-shaped metal patch and the second horn-shaped metal patch are symmetrical about the central axis of the width direction of the rectangular metal patch.

2. The compact folded transmission array antenna with extremely low profile according to claim 1, characterized in that, The projections of the upper metal patch (6) and the lower metal patch (8) are at a 45° angle.

3. The compact folded transmission array antenna with extremely low profile according to claim 1, characterized in that, The opening angle α of the double horn is adjustable. By adjusting the opening angle α, the phase compensation required for the transmission array (2) can be obtained. The opening angle α is the angle formed by the extension line of the end edge of the first horn-shaped metal patch or the second horn-shaped metal patch and the extension line of the perpendicular line of the central axis of the rectangular metal patch in the length direction.

4. The compact folded transmission array antenna with extremely low profile according to claim 1, characterized in that, By performing a horizontal mirroring operation on the polarized torsional reflector (5), a continuous phase change of 0°-360° is achieved in the transmission array (2).

5. The compact folded transmission array antenna with an extremely low profile according to claim 1, characterized in that, The reflective array (3) includes a number of periodically arranged torsional reflective units (5). The torsional reflective unit (5) includes a metal patch (9), a second dielectric substrate (10), and a first metal ground plate (11) arranged sequentially from top to bottom. The metal patch (9) includes an L-shaped metal patch, an isosceles right-angled triangular metal patch inscribed at the right angle of the L-shaped metal patch, and a first rectangular metal patch and a second rectangular metal patch respectively disposed at the ends of the two sides of the L-shaped metal patch and perpendicular to the two sides.

6. The compact folded transmission array antenna with an extremely low profile according to claim 5, characterized in that, The length L of the first rectangular metal patch and the second rectangular metal patch is adjustable, and the phase compensation required for the reflective array (3) can be obtained by adjusting L.

7. The compact folded transmission array antenna with an extremely low profile according to claim 6, characterized in that, The widths of the first rectangular metal patch and the second rectangular metal patch are the same as the width of the L-shaped metal patch, and the lengths and widths of the two sides of the L-shaped metal patch are the same.

8. The compact folded transmission array antenna with an extremely low profile according to claim 1, characterized in that, The planar feed (1) includes a second metal floor (14) and a V-groove metal patch (12) disposed above the second metal floor (14), with a second dielectric substrate (10) between them; the V-groove metal patch (12) is a metal patch with a V-groove in the center, and the V-groove is a V-groove structure with the bottom corner of the "V" cut off along the horizontal direction; a coordinate system o-xyz is established with the horizontal left and right direction as the x-axis and the vertical direction as the z-axis, the bottom edge of the V-groove is set along the x-axis direction, the groove opening is symmetrical about the y-axis, and the groove opening direction is along the positive y-axis direction.

9. The compact folded transmission array antenna with an extremely low profile according to claim 1, characterized in that, The transmission array (2) and the reflection array (3) have the same shape and structure, and their center projections overlap.

10. The compact folded transmission array antenna with an extremely low profile according to claim 1, characterized in that, The unit spacing of the double horn-shaped polarized torsional transmission unit (4) is P=0.333λ, where λ is the free space wavelength corresponding to 10 GHz.

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