Low-profile all-metal folding reflective array antenna

Abstract

The utility model discloses a low-profile all-metal folding reflective array antenna. The antenna comprises a feed source horn, a polarization torsion reflective array, a metal grid, a plastic support plate and a plurality of nylon columns. The feed source horn is placed in the center of the upper surface of the polarization torsion reflection array, the metal grid is placed above the polarization torsion reflection array, and the metal grid and the polarization torsion reflection array are supported and fixed through nylon columns; the metal grid is composed of a plurality of metal strips at equal intervals; the polarization torsion reflection array comprises a plurality of all-metal polarization torsion reflection units, and each reflection unit comprises a metal plate with a gap, an air layer and a metal floor which are sequentially arranged from top to bottom. The folding reflective array antenna is of a novel all-metal structure, the section height of a traditional reflective array antenna can be reduced by half, loss related to the dielectric substrate can be completely eliminated even if the folding reflective array antenna is located in a severe space environment, cost is reduced, and meanwhile the folding reflective array antenna is suitable for large-scale popularization and application. Good gain bandwidth and aperture efficiency can be realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of reflective array antennas, in particular to a low-profile all-metal folded reflective array antenna. Background Art

[0002] High-gain antennas are indispensable for most radar and long-range communication systems. Reflectarray antennas, among them, are widely used due to their light weight, compact size, and ease of fabrication. However, traditional reflectarray antennas are mostly based on dielectric substrates. When exposed to harsh space environments, the losses introduced by these substrates are significant, leading to a decrease in antenna performance. Furthermore, the presence of these substrates increases the cost of reflectarray antennas. Therefore, to address these issues, all-metal reflectarray antennas offer a better solution. In recent years, scholars both domestically and internationally have proposed several reflector elements with all-metal structures. For example, the paper "Design of a Ku-band reflectarray antenna consisting of only metallic surfaces" describes an all-metal element without a dielectric substrate; the paper "A Low-Cost Metal-Only Reflectarray Using Modified Slot-Type Phoenix Element With 360-Phase Coverage" describes an all-metal reflector element with a "Phoenix slot" design; and the paper "Steerable Spiral Slot Reflectarray at 66GHz Using Micromachined Movable Silicon Slab" describes an all-metal circularly polarized element.

[0003] In addition, the spatial feed causes the overall profile of the planar reflectarray antenna to be relatively high. To address this issue, existing technologies have designed folded reflectarray antennas using the principle of ray tracing. Based on the traditional planar reflectarray, this antenna introduces a metal grid with polarization-selective properties, integrating the feed and the reflectarray coplanarly. Compared with the traditional planar reflectarray, this antenna can reduce the reflectarray's profile by half. For example, the paper "Broadband Folded Reflectarray Antenna Using Single Layer Cross-Polarization Conversion Subwavelength Elements" designs a broadband folded reflectarray antenna using a single-layer subwavelength structure with polarization-twisted reflective elements, and the paper "Metasurface-Assisted Broadband Circularly Polarized Folded Reflectarray Antenna" designs a broadband circularly polarized folded reflectarray antenna. However, existing folded reflectarray antenna designs still rely on dielectric substrates, which can lead to corresponding loss and cost issues. Therefore, researching and designing a low-profile all-metal folded reflectarray antenna has certain scientific significance and application value. Utility Model Content

[0004] The purpose of the present invention is to provide a low-profile all-metal folded reflectarray antenna to address the problems existing in the above-mentioned prior art.

[0005] The technical solution for achieving the purpose of the utility model is: a low-profile all-metal folded reflective array antenna, the antenna including a feed horn, a polarization twist reflective array, a plastic support plate and a plurality of nylon columns, the feed horn is located at the center of the upper surface of the polarization twist reflective array, and the plastic support plate is placed at the bottom of the feed horn; the antenna also includes a metal grid, which is composed of a plurality of periodically arranged metal strips, is located above the polarization twist reflective array, and the two are supported and fixed by a plurality of nylon columns; the polarization twist reflective array includes a plurality of periodically arranged all-metal polarization twist reflective units, each all-metal polarization twist reflective unit includes a metal plate with a gap, an air layer and a metal floor arranged in sequence from top to bottom.

[0006] Furthermore, a plurality of metal strips are periodically arranged at equal intervals to form a rectangular structure.

[0007] Furthermore, the spacing between the metal strips is the same as the width of each metal strip.

[0008] Furthermore, the gap on the metal plate is formed by expanding on the basis of the fan-shaped arc gap structure, specifically: along the symmetry axis of the fan-shaped arc gap, an inner cut angle in the shape of an isosceles right triangle is added on the inner side of the center of the fan-shaped arc gap, the hypotenuse of the isosceles right triangle is an axis of the fan-shaped arc gap, the axis is perpendicular to the symmetry axis, and the right angle of the isosceles right triangle is located at the diagonal corner of the fan-shaped arc gap opening; at the same time, a right-angled outer cut angle is formed on the outside of the fan-shaped arc gap along the horizontal and vertical directions from the outer diameter of the fan-shaped arc gap, and the horizontal and vertical directions are respectively along the two right-angled sides of the isosceles right triangle.

[0009] Furthermore, the opening angle α of the fan-shaped arc gap is adjustable, so as to achieve continuous reflection phase change of the all-metal polarization twist reflection unit.

[0010] Furthermore, the opening angle α has a value range of [10°, 113°].

[0011] Furthermore, the all-metal polarization twist reflection unit is arranged in a mirror image to achieve a 360° phase difference.

[0012] Furthermore, the spacing P of the all-metal polarization twisted reflection unit is 0.47λ, where λ is the free space wavelength corresponding to the user-designed center frequency.

[0013] Furthermore, the edges of the metal grid and the polarization twisted reflective array are both extended for installation and fixation, and the two have the same size and shape.

[0014] Furthermore, the metal plate is a rectangular structure, and the axis of symmetry of the fan-shaped arc gap is set along the diagonal line of the rectangle.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] (1) The all-metal polarization twisted reflection unit proposed in the present invention does not use any dielectric substrate, which reduces the cost while avoiding the loss caused by the dielectric substrate in harsh space environments.

[0017] (2) The all-metal polarization twist reflection unit structure proposed in the present invention can change the polarization characteristics of electromagnetic waves and can better achieve a 90° polarization twist of the incident wave.

[0018] 3) Compared with traditional reflectarray antennas, the low-profile all-metal folded reflectarray antenna proposed in this utility model changes the propagation path of electromagnetic waves from the feed source by introducing a metal grid, so that the cross-section of the antenna is reduced to 1 / 2 of the original. At the same time, the antenna has an all-metal structure, which can eliminate the losses associated with the dielectric substrate even in harsh space environments, and can achieve good gain bandwidth and aperture efficiency.

[0019] The present invention is described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG is a structural diagram of a low-profile all-metal folded reflectarray antenna in one embodiment, wherein Figure 1 (a) is a three-dimensional schematic diagram of a low-profile all-metal folded reflectarray antenna. Figure 1 (b) is a side view of the low-profile all-metal folded reflectarray antenna.

[0021] Figure 2 FIG. 4 is a top view of an all-metal polarization twist reflector unit in one embodiment.

[0022] Figure 3 A side view of an all-metal polarization twist reflector unit in one embodiment.

[0023] Figure 4 3D schematic diagram of metal strips of a low-profile all-metal folded reflectarray antenna in one embodiment.

[0024] Figure 5 Graphs showing the reflection and transmission amplitudes of x-polarized waves and y-polarized waves by the metal strips of a low-profile all-metal folded reflectarray antenna in an embodiment in the frequency range of 8-12 GHz.

[0025] Figure 6 Graphs of reflection amplitude and phase of an all-metal polarization twisted reflection unit of a low-profile all-metal folded reflectarray antenna at different slot opening angles at frequencies of 9.5 GHz, 10 GHz, and 10.5 GHz in one embodiment.

[0026] Figure 7 Graph showing reflection amplitude and phase of an all-metal polarization twisted reflection unit of a low-profile all-metal folded reflectarray antenna at different slot opening angles within an incident angle range of 0°-40° in one embodiment.

[0027] Figure 8 Graphs of reflection amplitude and phase of an all-metal polarization twisted reflection unit and its mirror image state at different slot opening angles of a low-profile all-metal folded reflectarray antenna in one embodiment are shown.

[0028] Figure 9 1 is a simulated E-plane radiation pattern of a low-profile all-metal folded reflectarray antenna at 10 GHz in one embodiment.

[0029] Figure 10 1 is a simulated H-plane radiation pattern of a low-profile all-metal folded reflectarray antenna at 10 GHz in one embodiment.

[0030] Figure 11 Graph showing the gain and aperture efficiency of a simulated low-profile all-metal folded reflectarray antenna in one embodiment. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0032] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0033] In one embodiment, combined Figures 1 to 3 , provides a low-profile all-metal folded reflectarray antenna, the antenna comprising a feed horn 1, a polarization twist reflectarray 2, a plastic support plate 4 and a plurality of nylon columns 5, the feed horn 1 is located at the center of the upper surface of the polarization twist reflectarray 2, and the plastic support plate 4 is placed at the bottom of the feed horn 1; the antenna also comprises a metal grid 3, the metal grid 3 is composed of a plurality of periodically arranged metal strips 7, is located above the polarization twist reflectarray 2, and the two are supported and fixed by a plurality of nylon columns 5; the polarization twist reflectarray 2 comprises a plurality of periodically arranged all-metal polarization twist reflective units 6, each of the all-metal polarization twist reflective units 6 comprises a metal plate 8 with a gap, an air layer 9 and a metal floor 10 arranged in sequence from top to bottom.

[0034] Here, the nylon column 5 is used but not limited to it.

[0035] Furthermore, in one embodiment, Figure 4 As shown, a number of metal strips 7 are periodically arranged at equal intervals to form a rectangular structure.

[0036] In some embodiments, the spacing between the metal strips 7 is the same as the width of each metal strip 7 .

[0037] Preferably, the metal strips have a spacing of d1 = 1.5 mm, a width of d2 = 1.5 mm, and a thickness of t = 0.4 mm.

[0038] Furthermore, in one embodiment, the gap on the metal plate 8 is expanded and formed on the basis of the fan-shaped arc gap structure, specifically: along the symmetry axis of the fan-shaped arc gap, an inner cut angle in the shape of an isosceles right triangle is added on the inner side of the center of the fan-shaped arc gap, and the hypotenuse of the isosceles right triangle is an axis of the fan-shaped arc gap (the axis not passing through the center of the circle), which is perpendicular to the symmetry axis, and the right angle of the isosceles right triangle is located at the diagonal angle of the fan-shaped arc gap opening; at the same time, a right-angled outer cut angle is formed on the outside of the fan-shaped arc gap from the outer diameter of the fan-shaped arc gap along the horizontal and vertical directions, respectively, and the horizontal and vertical directions are along the two right-angled sides of the isosceles right triangle, respectively.

[0039] Here, the opening angle α of the fan-shaped arc gap is adjustable, so as to achieve continuous reflection phase change of the all-metal polarization twist reflection unit 6 .

[0040] Preferably, in some embodiments, the opening angle α has a value range of [10°, 113°].

[0041] Preferably, in some embodiments, the outer diameter R1 of the sector-shaped arc gap is 6.6 mm, and the inner diameter R2 is 5.2 mm; the length S of the right-angled side of the inner cut angle of the isosceles right triangle is 9.1 mm.

[0042] Preferably, in some embodiments, the metal plate 8 is a rectangular structure, and the axis of symmetry of the fan-shaped arc gap is arranged along the diagonal of the rectangle. According to the electric field vector principle, the electric field incident along the y-axis (the x-axis is horizontally to the right, the z-axis is vertically upward, and the y-axis complies with the right-hand principle) can be decomposed into the uv vector direction along the diagonal. The rational design structure of the units placed along the diagonal can ensure that: the reflected electric field in the u-axis direction does not change direction, the reflected electric field in the v-axis direction is inverted, and the final synthesized wave is along the x-direction.

[0043] Furthermore, in one embodiment, the all-metal polarization twist reflection unit 6 is mirror-imaged to achieve a 360° phase difference.

[0044] Furthermore, in one embodiment, the pitch P of the all-metal polarization twisted reflection unit 6 is 0.47λ, where λ is the free space wavelength corresponding to the user-designed center frequency.

[0045] Furthermore, in one embodiment, the edges of the metal grid 3 and the polarization twisted reflective array 2 are both extended for installation and fixation, and the two have the same size and shape.

[0046] Preferably, in some embodiments, the thickness H of the air layer 9 is 7 mm.

[0047] Preferably, in some embodiments, the vertical distance between the lower surface of the metal grid 3 and the upper surface of the polarization twisted reflective array 2 is 120 mm.

[0048] As a specific example, in one of the embodiments, the present invention is further verified and explained.

[0049] In this embodiment, a low-profile all-metal folded reflectarray antenna includes a feed horn 1, a polarization twist reflectarray 2, a metal grid 3, a plastic support plate 4, and several nylon posts 5. The feed horn 1 is placed at the center of the upper surface of the polarization twist reflectarray 2, and the metal grid 3 is placed above the polarization twist reflectarray 3. The two are supported and fixed by nylon posts 5. The plastic support plate 4 is placed at the bottom of the feed horn 1. The polarization twist reflectarray 2 is composed of 625 polarization twist reflective units 6. To facilitate installation and fixation, the polarization grid 3 and the polarization twist reflectarray 2 are of the same size and shape after being expanded at the edges. The array diameter is 370 mm. The nylon posts 5 between the polarization grid 3 and the polarization twist reflectarray 2 are 120 mm tall.

[0050] Depend on Figure 5 It can be seen that in the 8-12 GHz frequency band, the metal grid has a reflection amplitude of less than -20 dB for the incident x-polarized wave, and a transmission amplitude of about 0 dB; the reflection amplitude of the y-polarized wave is about 0 dB, and the transmission amplitude is less than -30 dB, indicating that the metal grid can achieve almost total transmission of the incident x-polarized wave and almost total reflection of the incident y-polarized wave, and has good polarization selection characteristics.

[0051] Depend on Figure 6 and Figure 7 It can be seen that the all-metal polarization twist reflection unit 6 has good reflection amplitude and almost linear phase coverage at different frequencies and different incident angles.

[0052] Depend on Figure 8 It can be seen that the all-metal polarization twist reflection unit 6 forms two different states through the mirror unit method, with equal reflection amplitudes and a phase difference of 180°; the fan-shaped gap opening angle varies in the range of 10°-113°, and the reflection amplitudes of the all-metal polarization twist reflection unit 6 are all greater than -0.5dB, and a continuous 360° phase change is achieved, which indicates that the reflection unit 6 has good reflection performance.

[0053] Depend on Figure 9 and Figure 10As can be seen, at 10 GHz, the main lobe directions of both the E-plane and H-plane of the reflectarray antenna based on the all-metal polarization twist unit are at 0°, consistent with the design. The simulated sidelobe level and cross-polarization of the E-plane are -21.7 dB and -33.9 dB, respectively, while the simulated sidelobe level and cross-polarization of the H-plane are -18.7 dB and -33.9 dB, respectively.

[0054] Depend on Figure 11 Simulation results for a reflectarray antenna based on an all-metal polarization twist unit show a gain of 29.2 dBi at 10 GHz and a maximum aperture efficiency of 51.9%. Furthermore, the reflectarray antenna achieves a 1-dB gain bandwidth of 9% and a 3-dB gain bandwidth of 28%.

[0055] The utility model discloses a low-profile all-metal folded reflectarray antenna, which is a new type of all-metal structure. It utilizes the principle of ray tracing to introduce a metal grid with polarization-selective characteristics, and integrates the feed source and the reflectarray coplanarly. This not only reduces the cross-sectional height of the traditional reflectarray antenna by half, but also completely eliminates the losses associated with the dielectric substrate even in harsh space environments, thereby achieving good gain bandwidth and aperture efficiency while reducing costs.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrative purposes. Without departing from the spirit and scope of the present invention, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A low-profile all-metal folded reflectarray antenna, comprising a feed horn (1), a polarization twist reflectarray (2), a plastic support plate (4), and a plurality of nylon columns (5), wherein the feed horn (1) is located at the center of the upper surface of the polarization twist reflectarray (2), and the plastic support plate (4) is placed at the bottom of the feed horn (1), characterized in that: The invention also includes a metal grid (3), which is formed by a plurality of metal strips (7) arranged periodically and is located above the polarization twist reflection array (2), and the two are supported and fixed by a plurality of nylon columns (5); the polarization twist reflection array (2) includes a plurality of periodically arranged full-metal polarization twist reflection units (6), and each full-metal polarization twist reflection unit (6) includes a metal plate (8) with a gap, an air layer (9) and a metal floor (10) arranged in sequence from top to bottom.

2. The low-profile all-metal folded reflectarray antenna according to claim 1, characterized in that: A plurality of metal strips (7) are periodically arranged at equal intervals to form a rectangular structure.

3. The low-profile all-metal folded reflectarray antenna according to claim 2, characterized in that: The spacing between the metal strips (7) is the same as the width of each metal strip (7).

4. The low-profile all-metal folded reflectarray antenna according to claim 1, wherein: The gap on the metal plate (8) is formed by expanding on the basis of the fan-shaped arc gap structure, specifically: along the symmetry axis direction of the fan-shaped arc gap, an inner cut angle in the shape of an isosceles right triangle is added on the inner side of the center of the fan-shaped arc gap, the hypotenuse of the isosceles right triangle is an axis of the fan-shaped arc gap, the axis is perpendicular to the symmetry axis, and the right angle of the isosceles right triangle is located at the diagonal angle of the fan-shaped arc gap opening; at the same time, a right-angled outer cut angle is formed on the outer side of the fan-shaped arc gap along the horizontal and vertical directions from the outer diameter of the fan-shaped arc gap, and the horizontal and vertical directions are respectively along the two right-angled sides of the isosceles right triangle.

5. The low-profile all-metal folded reflectarray antenna according to claim 4, characterized in that: The opening angle α of the fan-shaped arc gap is adjustable, and is used to achieve continuous reflection phase change of the all-metal polarization twist reflection unit (6).

6. The low-profile all-metal folded reflectarray antenna according to claim 5, characterized in that: The value range of the opening angle α is [10°, 113°].

7. The low-profile all-metal folded reflectarray antenna according to claim 1, characterized in that: The all-metal polarization twisting reflection unit (6) is arranged in a mirror image to achieve a 360° phase difference.

8. The low-profile all-metal folded reflectarray antenna according to claim 1, wherein: The spacing P of the all-metal polarization twisted reflection unit (6) is 0.47λ, wherein λ is the free space wavelength corresponding to the user-designed center frequency.

9. The low-profile all-metal folded reflectarray antenna according to claim 1, wherein: The edges of the metal grid (3) and the polarization twisted reflective array (2) are both expanded for installation and fixation, and the two are identical in size and shape.

10. The low-profile all-metal folded reflectarray antenna according to claim 4, characterized in that: The metal plate (8) is a rectangular structure, and the symmetry axis of the fan-shaped arc gap is arranged along the diagonal line of the rectangle.

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