A metasurface-based beamforming array antenna

Abstract

The application discloses a kind of based on metasurface beamforming array antenna, the antenna array surface includes multiple column line sources, each column line source includes a power division feed network and multiple antenna radiation units, the antenna radiation unit is connected with the power division feed network by metallization feed hole, and the power division feed network is fed to the antenna radiation unit by the metallization feed hole;The metasurface is loaded on the antenna array surface, and the amplitude and phase of the electromagnetic wave radiated by the antenna array surface are regulated and controlled.By the above-mentioned optimization design of metasurface beamforming array antenna, phase scanning and metasurface beamforming are combined, one-dimensional array shaping and one-dimensional phase scanning are realized, beamforming and beam rapid scanning are realized, and the integration design of antenna array surface, power division feed network and metasurface loading is low in cost, and the profile height of the whole array surface is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of beamforming antenna technology, and more particularly to a beamforming array antenna based on a metasurface. Background Technology

[0002] Beamforming has wide applications in satellite communication and radar detection. Common beamforming beams include flat-top beams, low-sidelobe beams, and cosecant square beams. Different beamforming beams play a significant role in complex and varied application scenarios. Flat-top beams are widely used in scenarios with large-area coverage. For example, ground-orbiting satellites require wide beams to provide omnidirectional coverage of different areas, enabling wide-range information and data transmission and reception. This requires that the signals emitted by the satellite reach the target area with equal strength, a problem that flat-top beams can solve. Another example is the cosecant square beam, which is typically used for air-to-ground radar detection. This type of beam provides high gain in the horizontal direction, with the gain gradually decreasing at high elevation angles. This beam shape ensures that when a target moves at the same altitude, the echo signal strength received on the ground is essentially the same. The rapid decrease in beam gain at low elevation angles significantly reduces interference signals emitted from the ground, while the near-flat beam gain at high elevation angles allows the receiver to receive signals of the same strength even when the target moves over long distances, facilitating radar reception and signal processing.

[0003] Currently, there are three main methods for obtaining the aforementioned shaped beams: 1. Controlling the amplitude and phase of each element of the array antenna to obtain the target beam shape; 2. Performing secondary beam reconstruction on the plane wave using a reflector array; 3. Using a complex power divider network to control the amplitude and phase of different elements. Method 1 is simple in structure and achieves good results, making it a commonly used method in engineering. However, each channel requires independently adjustable phase shifters and attenuators, significantly increasing the cost of the radar. Method 2, while low-cost, uses horn feeds and reflectors, greatly increasing the array profile height and weight, rendering it unsuitable for many low-profile and lightweight applications. Method 3 is also a commonly used beamforming method in engineering. However, as the number of elements increases, the amplitude and phase required for the shaped beam become increasingly diverse, making the complexity of the power divider network unimaginable. It requires significant manpower for design and debugging, and in many compact arrays, the design space for the power divider network is severely limited, becoming a major factor restricting its development. The development of metasurfaces has been booming this year. Many scholars have used metasurfaces to shape plane waves, such as multi-beam and low-sidelobe beams. However, the feed size is too large. In order to obtain plane waves or quasi-plane waves, the distance between the feed and the metasurface is too far, which makes it difficult to meet the low profile requirements in engineering and cannot perform flexible beam scanning, thus failing to meet the requirements of current radar detection. Summary of the Invention

[0004] To address the technical problems existing in the background art, this invention proposes a beamforming array antenna based on metasurface.

[0005] The present invention proposes a beamforming array antenna based on a metasurface, comprising: an antenna array, a metasurface, and a substrate;

[0006] The antenna array includes multiple line sources, each of which includes a power divider feed network and multiple antenna radiating elements. The antenna radiating elements are connected to the power divider feed network through metallized feed holes, and the power divider feed network feeds the antenna radiating elements through the metallized feed holes.

[0007] The metasurface is loaded above the antenna array and is used to modulate the amplitude and phase of the electromagnetic waves radiated through the antenna array.

[0008] The substrate comprises four double-layer printed circuit boards arranged sequentially from top to bottom;

[0009] The metasurface is disposed on the top printed circuit board, the antenna radiating element is disposed on the second-top printed circuit board, the power divider feed network is disposed on the second-bottom printed circuit board, and the metallized feed hole is disposed through the two middle printed circuit boards to connect the power divider feed network and the antenna radiating element.

[0010] Preferably, the antenna radiating element is located above the power divider feed network.

[0011] Preferably, the metasurface is composed of an array of metal patches.

[0012] Preferably, the metal patches are disposed on the top and bottom surfaces of the top printed circuit board.

[0013] Preferably, the metal patch includes a circular patch located in the center and a rectangular annular patch surrounding the circular patch.

[0014] Preferably, the antenna radiating element is disposed on the top of the secondary top printed circuit board.

[0015] Preferably, the antenna radiating element is an array of radiating patches, and the radiating patches are provided with slots for impedance matching.

[0016] Preferably, the power divider network is composed of multiple power dividers with one-to-two and one-to-three stubs.

[0017] Preferably, the power distribution network is disposed on the bottom surface of the sub-bottom printed circuit board.

[0018] This invention proposes a metasurface-based beamforming array antenna. The antenna array includes multiple line sources, each comprising a power divider feed network and multiple antenna radiating elements. The antenna radiating elements are connected to the power divider feed network via metallized feed holes, which feed the radiating elements. A metasurface is loaded above the antenna array to modulate the amplitude and phase of the electromagnetic waves radiated through it. This optimized metasurface beamforming array antenna combines phase scanning and metasurface beamforming, achieving one-dimensional beamforming and one-dimensional phase scanning, thus realizing rapid beamforming and scanning. Furthermore, the integrated design of the antenna array, power divider feed network, and metasurface loading results in low cost and significantly reduced overall array profile height. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0020] Figure 2 This is a schematic diagram of the printed circuit board arrangement in one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0021] Figure 3 This is a schematic diagram of the structure of a metal patch in one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0022] Figure 4 This is a schematic diagram of the antenna radiating element in one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0023] Figure 5 This is a schematic diagram of the power divider feed network in one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0024] Figure 6 This is an azimuth scanning pattern of one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0025] Figure 7 This is a comparison diagram of elevation beamforming in one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Detailed Implementation

[0026] like Figures 1 to 7 As shown, Figure 1 This is a schematic diagram of one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Figure 2This is a schematic diagram of the printed circuit board arrangement in one embodiment of the metasurface-based beamforming array antenna proposed in this invention. Figure 3 This is a schematic diagram of the metal patch structure in one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Figure 4 This is a schematic diagram of the antenna radiating element in one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Figure 5 This is a schematic diagram of the power divider feed network in one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Figure 6 This is an azimuth scanning pattern of one embodiment of a metasurface-based beamforming array antenna proposed in this invention. Figure 7 This is a comparison diagram of elevation beamforming in one embodiment of a metasurface-based beamforming array antenna proposed in this invention.

[0027] Reference Figure 1 and 2 The present invention proposes a beamforming array antenna based on a metasurface, comprising: an antenna array and a metasurface;

[0028] The antenna array includes multiple line sources, each of which includes a power divider feed network 14 and multiple antenna radiating elements 13. The antenna radiating elements 13 are connected to the power divider feed network 14 through a metallized feed hole 7, and the power divider feed network 14 feeds the antenna radiating elements 13 through the metallized feed hole 7.

[0029] The metasurface is loaded above the antenna array and is used to modulate the amplitude and phase of the electromagnetic waves radiated through the antenna array.

[0030] In the specific operation of the metasurface-based beamforming array antenna in this embodiment, electromagnetic wave energy propagates from the input end to the output end of the power divider network. After propagating to the output end, the energy is coupled to the antenna radiating element 13 through the metallized feed aperture, thereby exciting the antenna element to radiate electromagnetic waves into space. When the electromagnetic wave propagates to the metasurface, the metasurface rearranges the phase of the incident electromagnetic wave so that the phase of the transmitted electromagnetic wave satisfies the phase distribution of the flat-top beam, and continues to radiate into space. The metasurface-based beamforming array antenna uses microstrip structures throughout. The phase of the electromagnetic wave is controlled by adjusting the physical parameters of the metasurface. The distance between the loaded metasurface and the antenna is close, and the overall array profile height is low, greatly reducing the number of channels in the array and lowering the system cost. It also eliminates the need to design complex and diverse power distribution networks. This array achieves one-dimensional phase scanning and one-dimensional beamforming, greatly reducing the number of channels and the profile height, making it worthy of widespread application.

[0031] In this embodiment, the proposed metasurface-based beamforming array antenna includes an antenna array comprising multiple line sources. Each line source includes a power divider feed network 14 and multiple antenna radiating elements 13. The antenna radiating elements 13 are connected to the power divider feed network 14 via metallized feed holes, and the power divider feed network 14 feeds the antenna radiating elements 13 through the metallized feed holes. The metasurface is loaded above the antenna array to modulate the amplitude and phase of the electromagnetic waves radiated through the antenna array. This optimized metasurface beamforming array antenna combines phase scanning and metasurface beamforming, achieving one-dimensional beamforming and one-dimensional phase scanning, thus realizing beamforming and rapid beam scanning. Furthermore, the integrated design of the antenna array, power divider feed network 14, and metasurface loading results in low cost and significantly reduced overall array profile height.

[0032] Reference Figure 2 In a specific embodiment, the antenna radiating element 13 is located above the power divider feed network 14. In the actual antenna design of this embodiment, a substrate is also included, comprising four double-layer printed circuit boards arranged sequentially from top to bottom.

[0033] The metasurface is set on the top printed circuit board 8, the antenna radiating element 13 is set on the second-top printed circuit board 9, the power divider feed network 14 is set on the second-bottom printed circuit board 10, and the metallized feed hole 7 is set through the two middle printed circuit boards.

[0034] Reference Figure 3 In the specific design of the metasurface, the metasurface is composed of an array of metal patches 12. Specifically, the metal patches 12 are disposed on the top and bottom surfaces of the top printed circuit board 8, forming a double-layer array. The metal patches 12 include a circular patch 15 located in the center and a rectangular annular patch 16 surrounding the circular patch 15, and the phase of the transmitted electromagnetic wave is controlled by changing the radius of the pattern.

[0035] Reference Figure 4 In the specific design of the antenna radiating element 13, the antenna radiating element 13 is located on top of the secondary top printed circuit board 9. Specifically, the antenna radiating element 13 adopts an array of radiating patches 17, and the radiating patches 17 are provided with slots 18 for impedance matching.

[0036] Reference Figure 5 In the specific design of the power divider feed network 14, the power divider feed network 14 is composed of multiple power dividers that split from one to two branches 20 and from one to three branches 21, allowing electromagnetic wave energy to propagate from the input end to the output end of the power divider network between different layers, and then couple the energy to the antenna radiating element 13 through the metallized feed aperture. In a specific arrangement, the power divider feed network 14 is located on the bottom surface of the sub-bottom printed circuit board 10.

[0037] The beamforming array antenna of this embodiment will be described in detail below through examples.

[0038] Reference Figure 2 The array antenna in this embodiment consists of four printed circuit boards, from top to bottom: top printed circuit board 8, second-top printed circuit board 9, second-bottom printed circuit board 10, and bottom printed circuit board 11. Each printed circuit board is a double-layer board. It includes, from top to bottom, a first layer 1, a second layer 2, a third layer 3, a first copper layer, a fourth layer 4, a fifth layer 5, a second copper layer, and a sixth layer 6, each with copper plating of different structures and shapes. The metasurface elements are printed on the first layer 1 and the second layer 2, the antenna radiating element 13 is printed on the third layer 3, and the power divider feed network 14 is printed on the fifth layer 5.

[0039] The first layer 1 and the second layer 2 are printed with periodically arranged metasurface units. Each unit consists of a circular patch 15 and a rectangular ring 16. The phase of the transmitted electromagnetic wave can be controlled by adjusting the radius of the circular patch 15, and the rectangular ring 16 can increase the phase modulation bandwidth of the metasurface.

[0040] The specific design process is as follows: First, the initial phase distribution of the electric field above the array antenna is obtained through simulation software (HFSS). Then, the target phase distribution required for the flat-top beam is obtained through a genetic algorithm. Finally, the initial phase distribution is subtracted from the target phase distribution to obtain the phase distribution required by the metasurface. Adjusting the radius of the circular patch 15 can yield different transmission phases, thus establishing a one-to-one correspondence between radius and phase. Finally, based on the phase distribution required by the metasurface, the metasurface unit distribution with different structural parameters can be obtained.

[0041] The third layer 3 is where the antenna radiating element 13 is located. Electromagnetic wave energy is radiated out through the radiating patch 17, and the "I"-shaped gap 18 is used for impedance matching of the antenna element.

[0042] In this embodiment, there are 10 (y-axis) × 12 (x-axis) antenna elements. The 10 elements on the y-axis form a group of line sources. They transmit the signal to the power divider feed network 14 through the metallized feed hole 7 and finally merge the signal into one path. In this embodiment, there are 12 line sources. By changing the excitation phase of the 12 line sources, beam scanning in the x-axis direction can be completed.

[0043] Overall, the array antenna of this embodiment includes several antenna elements in the y-axis direction. By controlling the structural dimensions of the metasurface, sufficient phase distribution is achieved, thereby achieving beamforming. In the x-axis direction, it includes several column line sources. Beam scanning in the x-axis direction can be achieved by controlling the phase of the column line source feed. Ultimately, this invention can realize phase scanning in the x-axis direction and beamforming in the y-axis direction.

[0044] The fifth layer (5) is where the power divider feed network (14) is located. In this embodiment, there are 12 power divider feed networks (14) along the y-axis, and their output ports correspond one-to-one with the antenna radiating elements (13). The power divider feed network (14) is composed of multiple one-to-two branches (20) and one-to-three branches (21), which allow electromagnetic wave energy to propagate from the input end to the output end of the power divider network between the fourth layer (4) and the sixth layer (6). After propagating to the output end, the energy is coupled to the antenna radiating element (13) of the third layer (3) through the metallized feed hole (7) on the fifth layer (5), thereby exciting the antenna element to radiate electromagnetic waves into space. When the electromagnetic wave propagates to the second layer (2), the metasurface element rearranges the phase of the incident electromagnetic wave so that the phase of the transmitted electromagnetic wave satisfies the phase distribution of the flat-top beam, and continues to radiate into space. The sixth layer (6) is a metal ground plane that is entirely covered with copper.

[0045] In summary, this array antenna not only combines phase scanning and metasurface beamforming to achieve one-dimensional array shaping and one-dimensional phase scanning, but also realizes the integrated design of the antenna array, power divider feed network 14 and metasurface loading, greatly reducing the profile height of the entire array.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A metasurface-based beamforming array antenna, characterized in that, include: Antenna array, metasurface, and substrate; The antenna array includes multiple line sources, each of which includes a power divider feed network (14) and multiple antenna radiating elements (13). The antenna radiating elements (13) are connected to the power divider feed network (14) through a metallized feed hole (7). The power divider feed network (14) feeds the antenna radiating elements (13) through the metallized feed hole (7). The metasurface is loaded above the antenna array and is used to modulate the amplitude and phase of the electromagnetic waves radiated through the antenna array. The substrate comprises four double-layer printed circuit boards arranged sequentially from top to bottom; The metasurface is disposed on the top printed circuit board (8), the antenna radiating element (13) is disposed on the second top printed circuit board (9), the power divider feed network (14) is disposed on the second bottom printed circuit board (10), and the metallized feed hole (7) is disposed through the two middle printed circuit boards to connect the power divider feed network (14) and the antenna radiating element (13).

2. The metasurface-based beamforming array antenna according to claim 1, characterized in that, The antenna radiating element (13) is located above the power divider feed network (14).

3. The metasurface-based beamforming array antenna according to claim 2, characterized in that, The metasurface is composed of an array of metal patches (12).

4. The metasurface-based beamforming array antenna according to claim 3, characterized in that, Metal patches (12) are disposed on the top and bottom surfaces of the top printed circuit board (8).

5. The metasurface-based beamforming array antenna according to claim 4, characterized in that, The metal patch (12) includes a circular patch (15) located in the center and a rectangular ring patch (16) surrounding the circular patch (15).

6. The metasurface-based beamforming array antenna according to claim 2, characterized in that, The antenna radiating unit (13) is located on top of the secondary top printed circuit board (9).

7. The metasurface-based beamforming array antenna according to claim 6, characterized in that, The antenna radiating element (13) adopts an array of radiating patches (17), and the radiating patches (17) are provided with slots (18) for impedance matching.

8. The metasurface-based beamforming array antenna according to claim 1, characterized in that, The power divider network (14) is composed of multiple power dividers that split into two branches (20) and three branches (21).

9. The metasurface-based beamforming array antenna according to claim 8, characterized in that, The power distribution network (14) is located on the bottom surface of the sub-bottom printed circuit board (10).

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