A single-layer broadband reflectarray antenna with independent dual-polarization control

Abstract

The present invention discloses a single-layer broadband reflectarray antenna with independent control of dual-linear polarization. The present invention realizes the x-polarization working state and the y-polarization working state of the reflectarray antenna by rotating the horn antenna 0° and 90° relative to the planar reflectarray; the planar reflectarray includes a plurality of reflective units, each of which includes a dielectric layer, a metal reflective layer and a metal backplane layer; the metal reflective layer includes a metal ring and a cross-shaped metal patch. The present invention realizes independent reflection responses in two directions of the reflective unit through a single degree of freedom, and relies on rotating the feed horn antenna to change the polarization working state of the array antenna. The present invention adopts a single-layer structure without air gaps, achieving low profile, lightweight, simple manufacturing and low cost, and adopts a continuous phase adjustable method. It is the first time to propose a single-layer broadband reflectarray antenna with independent dual-linear polarization and continuous phase adjustment, realizing a lightweight single-layer design while ensuring high aperture efficiency and broadband.

Description

Technical Field

[0001] The invention belongs to the technical field of microwaves and antennas, and relates to a single-layer broadband reflective array with independent control of dual-linear polarization. Background Art

[0002] High-gain antennas are crucial for long-distance communications. Traditional high-gain antennas include parabolic antennas and phased array antennas. Parabolic antennas offer a simple structure, high gain, and excellent broadband performance, but they are bulky and require high manufacturing precision. Phased array antennas offer high gain, a low profile, and adjustable beam direction, but they have a complex feed network and high losses. Reflectarray antennas combine these two advantages, offering a low profile and a small size. They are also easy to integrate into systems and have a wider range of applications.

[0003] At the same time, with the development of 5G technology, the amount of communication data is also increasing, which puts relatively high requirements on channel capacity. When increasing channel capacity, commonly used technologies include time division multiplexing, frequency division multiplexing and code division multiplexing. Later, some people proposed a dual-layer reflectarray with independent dual-polarization control (CS Geaney, M. Hosseini and SV Hum, Reflectarray Antennas for Independent Dual Linear and Circular Polarization Control [J]. IEEE Transactions on Antennas and Propagation, vol. 67, no. 9, pp. 5908-5918, Sept. 2019) and (L.-X. Wu et al., "Wideband Dual-Feed Dual-Polarized Reflectarray Antenna Using Anisotropic Metasurface [J]. IEEE Antennas and Wireless Propagation Letters, vol. 21, no. 1, pp. 129-133, Jan. 2022). On this basis, the function of polarization multiplexing was added, which can effectively increase the channel capacity and better cope with the current large-scale data communication situation. Some people also proposed a single-layer reflectarray with independent dual-polarization control (J. Yin, Q. Lou, H. Wang, ZNChen and W. Hong, Broadband Dual-Polarized Single-Layer Reflectarray Antenna With Independently Controllable 1-Bit Dual Beams[J].IEEE Transactions on Antennas and Propagation,vol.69,no.6,pp.3294-3302,June 2021), however, the dual-polarized independently controlled single-layer reflectarray involved in this paper adopts 1-bit phase modulation, which results in lower aperture efficiency.

[0004] Currently, dual-polarization independently controlled broadband antennas mostly adopt a multi-layer structure. The multi-layer structure means increased manufacturing difficulty and cost. In addition, long-distance wireless communication systems are mostly deployed in satellites or high towers.

[0005] Therefore, how to achieve a lightweight single-layer design while ensuring high aperture efficiency and broadband is also a key issue that needs to be considered during the design. Summary of the Invention

[0006] The present invention addresses the shortcomings of the prior art by providing a single-layer broadband reflectarray antenna with independent polarization control. While maintaining high gain and wide bandwidth, the present invention achieves dual-polarization independent control and a low profile through a single-layer structure. Furthermore, the antenna has the advantages of a simple unit structure and ease of integration.

[0007] The technical solution of the present invention to solve the above technical problems is:

[0008] A single-layer broadband reflectarray antenna with independent dual-polarization control, the main body of which includes:

[0009] a planar reflective array (4) serving as a reflective surface;

[0010] A horn antenna (5) serving as a feed source, which is located directly above the planar reflective array (4) and is rotatable about a central axis; the central axis is perpendicular to the planar reflective array (4);

[0011] The x-polarization working state and the y-polarization working state of the reflective array antenna of the present invention are realized by rotating the horn antenna (5) 0° and 90° relative to the plane reflective array (4).

[0012] The planar reflection array (4) comprises a plurality of periodically seamlessly distributed reflection units, wherein each reflection unit comprises a dielectric layer (2), and a metal reflection layer (1) and a metal backplane layer (3) respectively laid on the upper and lower layers of the dielectric layer (2); the metal reflection layer (1) comprises a metal ring (11), and a cross-shaped metal patch (12) located inside the metal ring (11), wherein a distance exists between the cross-shaped metal patch (12) and the metal ring (11); a first notch (121) is provided at the center of the cross-shaped metal patch (12), and a first notch (122) is provided at the center of the cross-shaped metal patch (12). The two arms on the same straight line are respectively provided with a second notch (122) and a third notch (123) of equal length and width, and the other two arms on the same straight line are respectively provided with a fourth notch (124) and a fifth notch (125) of equal length and width; the centers of the first notch (121), the second notch (122), and the third notch (123) are located on the same straight line, and there is a distance between them; the centers of the first notch (121), the fourth notch (124), and the fifth notch (125) are located on the same straight line, and there is a distance between them;

[0013] Preferably, the metal ring (11) of each reflective unit is seamlessly connected to the metal ring (11) of an adjacent reflective unit;

[0014] Preferably, the center of each reflective unit coincides with the center of the first notch (121) therein;

[0015] Preferably, the cross-shaped metal patches (12) of all the reflective units in the planar reflective array (4) have the same or different sizes;

[0016] Preferably, the planar reflective array (4) is quasi-circular in shape; each reflective unit generates different compensation phases when receiving x-polarized and y-polarized incident waves, thereby forming different beam directions for incident waves of different polarizations;

[0017] Preferably, the shape of the reflecting unit is square;

[0018] Preferably, the spacing P between the centers of adjacent reflective units is 1 / 2λ, where λ represents the wavelength of the central operating frequency of the reflective array antenna.

[0019] Preferably, there is a gap between the planar reflection array (4) and the horn antenna (5).

[0020] Preferably, the wide mouth of the horn antenna (5) faces the planar reflective array (4).

[0021] The present invention has the following advantages:

[0022] (1) The present invention realizes independent reflection responses in two directions of the reflection unit through a single degree of freedom. The independent phase response is achieved by forming a circular current around the non-working gap while avoiding the formation of a strong electric field at the gap to affect the state at the working gap. The polarization working state of the array antenna is changed by rotating the feed horn antenna, and the controllability is strong.

[0023] (2) The present invention adopts a single-layer structure without air gaps, achieving low profile, lightweight, simple manufacturing and low cost, and adopts a continuous phase adjustable method. It is the first time to propose a single-layer broadband reflectarray antenna with independent continuous phase adjustment of dual linear polarizations, realizing a lightweight single-layer design while ensuring high aperture efficiency and broadband.

[0024] (3) The unit has strong scalability and can realize circular polarization reflection under linear polarization feeding by designing phase compensation for different polarizations, and set up two linear polarization antennas with different angles and polarizations to form a high-gain circular polarization beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the reflective unit of the single-layer broadband reflectarray antenna with independent control of dual linear polarizations of the present invention;

[0026] Figure 2 1. It is a top view of the reflective unit of the single-layer broadband reflectarray antenna with independent control of dual linear polarizations according to the present invention;

[0027] Figure 3It is a side view of the reflection unit of the single-layer broadband reflectarray antenna with independent control of dual linear polarization according to the present invention along the y-axis direction;

[0028] Figure 4 It is a surface current diagram of the reflective unit of the single-layer broadband reflective array antenna with independent dual-polarization control of the present invention under the incidence of y-polarized electromagnetic waves;

[0029] Figure 5 This is a graph of reflection amplitude and reflection phase under the incidence of y-polarized electromagnetic waves when the length Lx of the hollow metal arm of the reflection unit of the dual-polarization independently controlled single-layer broadband reflectarray antenna of the present invention changes along the x-direction;

[0030] Figure 6-1 1 is a schematic diagram of the overall array of a single-layer broadband reflectarray antenna with independent control of dual-polarization according to the present invention, with the feed horn rotated 0°;

[0031] Figure 6-2 1. It is an overall schematic diagram of the array of a single-layer broadband reflectarray antenna with independent control of dual-polarization according to the present invention, wherein the feed horn is rotated 90°;

[0032] Figure 6-3 Schematic diagram of the structure of the horn antenna of the present invention; (a) is a bottom view, (b) is a side view, and (c) is a front view;

[0033] FIG7( a ) is a normalized E-plane radiation pattern of a single-layer broadband reflectarray antenna with independent dual-polarization control according to the present invention under x-polarization operating conditions at 10 GHz;

[0034] Figure 7(b) is the H-plane normalized radiation pattern of the single-layer broadband reflectarray antenna with independent dual-polarization control of the present invention at 10GHz in the x-polarization working state

[0035] FIG8( a ) is an E-plane normalized radiation pattern of a single-layer broadband reflectarray antenna with independent dual-polarization control according to the present invention in the y-polarization operating state at 10 GHz;

[0036] Figure 8(b) is the H-plane normalized radiation pattern of the single-layer broadband reflectarray antenna with independent dual-polarization control of the present invention at 10GHz in the y-polarization working state.

[0037] Figure 9 The measured gain and aperture efficiency of the single-layer broadband reflective array antenna with independent dual-polarization control at 10 GHz under different polarization working conditions are shown in Figure 2.

[0038] Markings in the figure: 1. Metal reflective layer, 11. Metal ring, 12. Cross-shaped metal patch, 121. First notch, 122. Second notch, 123. Third notch, 124. Fourth notch, 125. Fifth notch, 2. Dielectric layer, 3. Metal backplane, 4. Planar reflective array, 5. Horn antenna, 501. First metal sheet, 502. Second metal sheet, 503. First metal column, 504. Second metal column, 505. Third metal column, 506. Fourth metal column, 507. Fifth metal column, 508. Sixth metal column, 509. First metal surface, 510. Second metal surface. DETAILED DESCRIPTION

[0039] The present invention is further analyzed below in conjunction with specific embodiments, but the specific examples here are only used to explain this application and are not limited to the specific examples proposed here.

[0040] A single-layer broadband reflectarray antenna with independent dual-polarization control, such as Figure 6-1 、 6-2 The main body shown includes: a planar reflective array 4 and a horn antenna 5. By rotating the horn antenna 5 40° and 90° relative to the planar reflective array, the x-polarization working state and the y-polarization working state of the reflective array antenna of the present invention are realized.

[0041] The aperture plane of the horn antenna 5 is parallel to the aperture plane of the planar reflectarray 4 and the distance between them is 240 mm. When the long side of the aperture plane of the feed horn antenna 5 is parallel to the y-axis, that is, the rotation angle of the horn antenna is 0°, the single-layer broadband reflectarray antenna with independent dual-linear polarization control operates in the x-polarization state; when the long side of the aperture plane of the feed horn antenna 5 is parallel to the x-axis, that is, the rotation angle of the horn antenna is 90°, the single-layer broadband reflectarray antenna with independent dual-linear polarization control operates in the y-polarization state, that is, the working state of the single-layer broadband reflectarray antenna with independent dual-linear polarization control is switched by rotating the feed horn antenna around the z-axis to generate independently controllable x-polarization and y-polarization reflection beams.

[0042] The horn antenna 5 is used as a feed source, which is located directly above the plane reflection array 4 and can rotate around the central axis; the central axis is perpendicular to the plane reflection array 4; Figure 6-3The horn antenna 5 is a broadband horn antenna, including a horn structure channel, a first metal sheet 501, a second metal sheet 502, a first metal surface 509, a second metal surface 510, and six metal pillars (i.e., a first metal pillar 503, a second metal pillar 504, a third metal pillar 505, a fourth metal pillar 506, a fifth metal pillar 507, and a sixth metal pillar 508); the narrow opening of the horn structure channel is a closed opening, and the wide opening is an open end; the wide opening of the horn structure channel faces the plane reflection array 4; the first metal surface 509 and the second metal surface 510 are respectively provided on the symmetrical sides of the wide opening of the horn structure channel. The wide end of the speaker structure channel is further provided with a first metal sheet 501 and a second metal sheet 502 symmetrically around the central axis; the first metal sheet 501 and the second metal sheet 502 are located between the first metal surface 509 and the second metal surface 510, and one side of each is connected to the first metal surface 509 and the second metal surface 510 respectively; there is a gap between the first metal sheet 501 and the second metal sheet 502; three equally spaced metal pillars are respectively provided on the other two symmetrical sides of the wide end of the speaker structure channel, and the two ends of the metal pillars are connected to the sides of the first metal surface 509 and the second metal surface 510;

[0043] The planar reflective array 4 is quasi-circular in shape and serves as a reflective surface, comprising a plurality of periodically and seamlessly distributed reflective units; each reflective unit is square in shape and generates different compensation phases when subjected to x-polarized and y-polarized incident waves, thereby forming different beam directions for incident waves of different polarizations;

[0044] Each reflective unit includes a dielectric layer 2, and a metal reflective layer 1 and a metal backplane layer 3 respectively laid on the upper and lower layers of the dielectric layer 2; the metal reflective layer 1 includes a metal ring 11 and a cross-shaped metal patch 12 located inside the metal ring 11, and the cross-shaped metal patch 12 is spaced apart from the metal ring 11;

[0045] The cross-shaped metal patch 12 includes a first metal arm patch and a second metal arm patch vertically arranged along the positive and negative x directions and the positive and negative y directions respectively;

[0046] The center of the cross-shaped metal patch 12, i.e., the intersection of the first metal arm patch and the second metal arm patch, is provided with a first notch 121;

[0047] The two arms on the second metal arm patch are respectively provided with a second notch 122 and a third notch 123 of equal length and width, and the other two arms on the first metal arm patch are respectively provided with a fourth notch 124 and a fifth notch 125 of equal length and width; the centers of the first notch 121, the second notch 122, and the third notch 123 are located on the same straight line, and there is a distance between them; the centers of the first notch 121, the fourth notch 124, and the fifth notch 125 are located on the same straight line, and there is a distance between them; the center of each reflective unit coincides with the center of the first notch 121 therein;

[0048] The metal ring 11 of each reflective unit is seamlessly connected to the metal ring 11 of the adjacent reflective unit; the spacing P between the centers of adjacent reflective units is 1 / 2λ, where λ represents the wavelength of the center operating frequency of the reflective array antenna;

[0049] The sizes of the cross-shaped metal patches 12 of all the reflective units in the planar reflective array 4 are not exactly the same, but they can also be exactly the same;

[0050] The x-axis length from the second notch 122 to the end of the first metal arm patch is Lx, the x-axis length from the third notch 123 to the end of the first metal arm patch is Lx, the y-axis length from the fourth notch 124 to the end of the second metal arm patch is Ly, and the y-axis length from the fifth notch 125 to the end of the second metal arm patch is Ly. Both Lx and Ly are adjustable to achieve independent phase adjustment of the reflector unit in the x and y operating states. The line width of the metal ring 11 is g. The widths of the first and second metal arm patches are w1. The distance between the sidewall of the fifth notch 125 and the nearest sidewall of the first metal arm patch is w.

[0051] The dielectric substrate used in the dielectric layer 2 is of the model F4B, with a relative dielectric constant of 2.2, a loss tangent of 0.001, and a thickness h of 2 mm.

[0052] The metal reflective layer 1 and the metal back plate layer 3 are made of copper with a thickness of 0.036 mm.

[0053] The reflection phases of x-polarized and y-polarized incident waves are adjusted by changing the arm length Lx along the x-direction and the arm length Ly along the y-axis, respectively. The adjustment phases of Lx and Ly are both 2.6mm to 6.5mm. As shown in the figure, when the arm length Lx in the x-direction is changed, the reflection phase curves of the y-polarized incident wave basically coincide with each other, indicating that the reflector unit operates independently under the incidence of x-polarized and y-polarized incident waves, and the reflection amplitudes are both greater than -0.1dB. The reflection phase coverage range is greater than 320°, meeting the design requirements of a single-layer broadband reflectarray antenna with independent control of dual linear polarizations.

[0054] In summary, w=1.2 mm, w1=3 mm, g=0.5 mm, and p=15 mm are preferably selected to form the reflective unit. The reflective array 4 has a diameter of 285 mm and includes 293 reflective units.

[0055] This embodiment also provides a phase control method for the above-mentioned single-layer broadband reflectarray antenna with independent control of dual linear polarizations, including the following steps:

[0056] Step 1: First, design a reflection unit that can generate independent phase responses to x-polarized incident waves and y-polarized incident waves. This reflection unit can cover a phase range of more than 320°.

[0057] Step 2: Calculate the phase compensation required for the x-polarized incident wave and the y-polarized incident wave according to the directions of the x-polarized wave and the y-polarized wave as required and the distance from the horn antenna 5 to the planar reflective array 4 .

[0058] Step 3: According to the correspondence table between phase compensation and size of the plane reflective array 4 , the required phase compensation is converted into the corresponding size of the plane reflective array 4 , and then the actual reflective array surface is arranged according to the size of the plane reflective array 4 .

[0059] The present invention realizes independent reflection response in two directions of the reflection unit through single degree of freedom. The independent phase response is achieved by forming a ring current around the non-working gap. Figure 4 ;

[0060] Figure 5 This is a graph of reflection amplitude and reflection phase under the incidence of y-polarized electromagnetic waves when the length Lx of the hollow metal arm of the reflection unit of the dual-polarization independently controlled single-layer broadband reflectarray antenna of the present invention changes along the x-direction;

[0061] Depend on Figure 7(a) and 7(b) As can be seen, when the single-layer broadband reflectarray antenna with independent dual-polarization control operates in the x-polarization state, the E-plane main beam direction is 15°, consistent with expectations. The E-plane sidelobe level and cross-polarization are less than -18 dB and -41 dB, respectively. The H-plane sidelobe level and cross-polarization are less than -18 dB and -29 dB, respectively.

[0062] Depend on Figure 8(a) and 8(b) As can be seen, when the single-layer broadband reflectarray antenna with independent dual-polarization control operates in the y-polarization state, the E-plane main beam direction is -15°, consistent with expectations. The E-plane sidelobe level and cross-polarization are less than -13dB and -37dB, respectively. The H-plane sidelobe level and cross-polarization are less than -13dB and -30dB, respectively.

[0063] Depend on Figure 9As can be seen, when this example operates in the x-polarization state, the maximum gain is 25dBi, the corresponding aperture efficiency is 37%, and the 3dB gain bandwidth is 20.9%. When this example operates in the y-polarization state, the maximum gain is 24.5dBi, the corresponding aperture efficiency is 35%, and the 3dB gain bandwidth is 22.7%.

[0064] In summary, the dual-polarization independently controlled single-layer broadband reflectarray antenna of the present invention can achieve independent phase adjustment of x-polarization and y-polarization by changing the lengths of two sets of metal arms Lx and Ly, thereby realizing independent beam control of the two polarizations. At the same time, it can achieve switching between the x-polarization and y-polarization working states by rotating the feed horn antenna around the z-axis, and has good radiation performance.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A single-layer broadband reflectarray antenna with independent dual-polarization control, characterized in that include: a planar reflective array (4) serving as a reflective surface; A horn antenna (5) serving as a feed source, which is located directly above the planar reflective array (4) and is rotatable about a central axis; the central axis is perpendicular to the planar reflective array (4); The x-polarization working state and the y-polarization working state of the reflective array antenna are realized by rotating the horn antenna (5) 0° and 90° relative to the planar reflective array (4); The planar reflection array (4) comprises a plurality of periodically seamlessly distributed reflection units, wherein each reflection unit comprises a dielectric layer (2), and a metal reflection layer (1) and a metal backplane layer (3) respectively laid on the upper and lower layers of the dielectric layer (2); the metal reflection layer (1) comprises a metal ring (11), and a cross-shaped metal patch (12) located within the metal ring (11), and a distance exists between the cross-shaped metal patch (12) and the metal ring (11); The cross-shaped metal patch (12) has a first notch (121) at its center, and two arms located on the same straight line have a second notch (122) and a third notch (123) of equal length and width, respectively, and the other two arms located on the same straight line have a fourth notch (124) and a fifth notch (125) of equal length and width, respectively; the centers of the first notch (121), the second notch (122), and the third notch (123) are located on the same straight line, and there is a distance between them; the centers of the first notch (121), the fourth notch (124), and the fifth notch (125) are located on the same straight line, and there is a distance between them; The shape of the planar reflection array (4) is quasi-circular; each reflection unit generates different compensation phases when subjected to x-polarized and y-polarized incident waves, thereby forming different beam directions for incident waves of different polarizations.

2. The reflectarray antenna according to claim 1, wherein: The metal ring (11) of each reflection unit is seamlessly connected to the metal ring (11) of an adjacent reflection unit.

3. The reflectarray antenna according to claim 1, wherein: The center of each reflection unit coincides with the center of the first notch (121) therein.

4. The reflectarray antenna according to claim 1, wherein: The cross-shaped metal patches (12) of all reflective units in the planar reflective array (4) have exactly the same size.

5. The reflectarray antenna according to claim 1, wherein: The sizes of the cross-shaped metal patches (12) of all the reflective units in the planar reflective array (4) are not exactly the same.

6. The reflectarray antenna according to claim 1, wherein: The spacing P between the centers of adjacent reflective units is 1 / 2λ, where λ represents the wavelength of the central operating frequency of the reflective array antenna.

7. The reflectarray antenna according to claim 1, wherein: There is a gap between the planar reflection array (4) and the horn antenna (5).

8. The reflectarray antenna according to claim 1 or 7, characterized in that: The wide mouth of the horn antenna (5) faces the planar reflection array (4).

Images