Low sidelobe phased array antenna based on reconfigurable radiating elements

Abstract

This invention relates to a low-sidelobe phased array antenna based on a reconfigurable metasurface, belonging to the field of millimeter-wave radar systems. It includes, from top to bottom, a spherical wave generating device, a 2-bit reconfigurable radiating element, and a feeding network. The feeding network powers the 2-bit reconfigurable radiating element, and the radiated signal from the 2-bit reconfigurable radiating element is generated into a spherical wave by the spherical wave generating device and radiated outwards. The 2-bit reconfigurable radiating element is composed of PIN diodes, radiating patches, metal vias, phase adjustment components, a reflector ground plane, a multilayer PCB structure, and an SMA feeding structure. By adjusting the PIN diodes and phase adjustment components, the radiation phase of the radiating element is adjusted to achieve reconfigurable radiation pattern, thereby realizing beam pointing electrical scanning. This invention effectively reduces the antenna sidelobes during large-angle scanning, expands the scanning range of the antenna array, and provides a new design approach for low-cost, large-angle scanning, and high-performance phased array antennas.

Description

Technical Field

[0001] This invention belongs to the field of millimeter-wave radar systems, specifically relating to a low-cost, low-profile, low-sidelobe phased array antenna element and a spherical wave conversion device. Background Technology

[0002] In phased array antenna design, low cost, low sidelobes, and large-angle scanning have always been key research directions. To achieve large-angle scanning in a phased array antenna, the spacing between antenna array elements must be small enough to meet minimum spacing requirements. However, excessively small antenna element spacing poses a significant challenge to the design of the transceiver / receiver (T / R) components. Furthermore, in active phased array systems, the cost of the T / R components accounts for more than 50% of the total system cost. Reducing the cost of the T / R components is crucial for low-cost phased array design. Currently, methods for achieving low-cost phased arrays mainly involve reducing the number of active channels, such as sparse arrays or sparsely distributed arrays, high-gain phased array feed antennas, liquid crystal phased arrays, and PIN diode-based reflective or transmissive phased arrays. In sparse array designs, the random array layout makes interconnection between T / R components and passive antenna elements difficult. High-gain phased array feed antennas, due to limitations imposed by the reflector surface or lens focal diameter ratio, have a high profile, making them difficult to apply to low-profile military platforms. Furthermore, the large size and weight of the reflector and lens further limit the application of this type of phased array in the radar field. While liquid crystal phased arrays are inexpensive, their beam scanning speed is much slower than traditional phased arrays because the phase transition time of liquid crystal materials is much longer than the on / off time of semiconductor devices. Although inexpensive PIN diodes can achieve faster beam response speeds in low-cost phased arrays, the large phase error at the aperture and the insertion loss of the diodes result in significant gain loss, leading to a poor overall system G / T value. Simultaneously, the narrowband limitation of the individual elements makes wideband applications difficult. Moreover, traditional reconfigurable transmission or reflection array antennas use open-feed methods to excite each element, which reduces the complexity of network design but results in extremely high profiles, limiting their application.

[0003] Currently, a great deal of research has been conducted both domestically and internationally on low-cost phased array antennas. However, most of this research focuses on sparse array distribution and reconfigurable metamaterial antennas based on open-feed methods, and most are 1-bit, resulting in a small scanning range and poor aperture efficiency. This invention, based on a low-profile 2-bit reconfigurable element and a spherical wave converter, designs a low-cost phased array antenna with high aperture efficiency, a large scanning angle, and low sidelobe levels, effectively addressing the aforementioned shortcomings and possessing significant application value in the field of radar antennas. Summary of the Invention

[0004] The technical problem to be solved by this invention is: To address the high cost of T / R components in traditional phased array antennas and the poor scanning performance and high profile issues of traditional low-cost phased array antenna designs, this invention provides a low-sidelobe phased array antenna based on reconfigurable radiating elements. This effectively achieves low-cost, low-sidelobe design for phased array antennas and can be widely applied in engineering practice.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A low-sidelobe phased array antenna based on a reconfigurable radiating element is characterized by comprising a spherical wave generating device, a 2-bit reconfigurable radiating element, and a feeding network arranged sequentially from top to bottom; the feeding network supplies power to the 2-bit reconfigurable radiating element, and the radiated signal of the 2-bit reconfigurable radiating element is radiated out after passing through the spherical wave generating device.

[0006] A further technical solution of the present invention: the spherical wave generating device can be realized by a lens or a metamaterial planar transmission array.

[0007] A further technical solution of the present invention: The 2-bit reconfigurable radiating unit includes a first PCB board, a second PCB board, and a third PCB board arranged sequentially from top to bottom. The first PCB board is provided with a radiating component and a first feeding structure, and the third PCB board is provided with a phase adjustment component, a second feeding structure, and a third feeding structure. The first feeding structure, the second feeding structure, and the third feeding structure constitute the feeding component, which feeds the radiating component and adjusts the phase through the phase adjustment component. A further technical solution of the present invention: the radiating component includes a first radiating patch and a second radiating patch, the first radiating patch being connected to a first feeding structure via a first PIN diode, and the second radiating patch being connected to the first feeding structure via a second PIN diode.

[0008] A further technical solution of the present invention: the first radiating patch and the second radiating patch are symmetrically located on both sides of the first feeding structure.

[0009] A further technical solution of the present invention: the phase adjustment component includes a first phase delay line and a second phase delay line; the first phase delay line is connected to the second feed structure through a fourth PIN diode and to the third feed structure through a third PIN diode; the second phase delay line is connected to the second feed structure through a sixth PIN diode and to the third feed structure through a fifth PIN diode.

[0010] A further technical solution of the present invention: a power supply signal is connected between the first PCB board and the third PCB board through a metal via, the metal via penetrating the second PCB board, with the upper end connected to the first power supply structure and the lower end connected to the second power supply structure.

[0011] A further technical solution of the present invention: an intermediate ground plane is provided between the first PCB board and the second PCB board. A further technical solution of the present invention: a bottom ground plane is provided on the back of the third PCB board, the middle ground plane is an antenna radiating unit reflective ground plane and a strip upper ground plane, and the bottom ground plane is a strip lower lower ground plane.

[0012] A method for reconfigurable radiation pattern is characterized in that the radiation phase of the radiation unit is adjusted by adjusting the switching of the first PIN diode, the second PIN diode, the third PIN diode, the fourth PIN diode, the fifth PIN diode, and the sixth PIN diode in conjunction with the first phase delay line and the second phase delay line to achieve reconfigurable radiation pattern, thereby realizing beam pointing electrical scanning.

[0013] The beneficial effects of this invention are as follows: This invention provides a low-sidelobe phased array antenna based on a reconfigurable radiating element, solving the problems of high cost, long design cycle, and complex T / R component debugging in traditional phased array antennas. This design method overcomes the requirements of traditional phased array antenna components regarding element spacing, and is expected to achieve rapid electronic beam scanning over a larger angle range with the same aperture. The design method is based on a 2-bit reconfigurable radiating element, a spherical wave conversion device, and a feeding network. The reconfigurable element consists of six low-loss, high-isolation PIN diodes, a radiating patch, metal vias, a reflective ground plane, a multilayer PCB structure, and an SMA feeding structure. The spherical wave conversion device can be implemented using a lens or a metamaterial planar transmission array. The introduction of spherical waves can significantly reduce sidelobes during large-angle scanning, providing a new design approach for low-cost, low-sidelobe, large-angle scanning phased array antennas. Attached Figure Description

[0014] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0015] Figure 1 A top view of the designed 2-bit unit.

[0016] Figure 2 Side view of the designed 2-bit unit.

[0017] Figure 3 Side view of the designed 2-bit unit.

[0018] Figure 4 Side view of the designed 2-bit unit.

[0019] Figure 5 The phase distribution of the designed spherical wave conversion device.

[0020] Figure 6 The phase curve of the designed 2-bit cell was simulated.

[0021] Figure 7 The scanning pattern of the designed phased array antenna.

[0022] 1-First PIN diode, 2-Second PIN diode, 3-Third PIN diode, 4-Fourth PIN diode, 5-Fifth PIN diode, 6-Sixth PIN diode, 7-First radiating patch, 8-Second radiating patch, 9-SMA feed structure, 10-First phase delay line, 11-Second phase delay line, 12-First feed structure, 13-Intermediate ground plane, 14-First PCB board, 15-Second PCB board, 16-Third PCB board, 17-Bottom ground plane, 18-Metal via, 19-Spherical wave generator, 20-2-Bit reconfigurable radiating element, 21-Feed network, 22-Second feed structure, 23-Third feed structure. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0024] This invention designs a low-profile 2-bit reconfigurable cell. The radio frequency excitation signal is transmitted to the topmost radiating patch through a phase delay line structure and a metal via structure. The good matching of the radiating cell is achieved by adjusting the position and size of the feeding structure, the size of the metal via and the ground plane opening, and the size of the radiating patch. The different phase states of the radiating cell in the far field are achieved by controlling the on and off of PIN diodes at different positions. The aperture quantization error is reduced by using a spherical wave generation device to achieve large-angle, low-sidelobe scanning.

[0025] The designed spherical wave generator can be implemented using a dielectric lens antenna or a planar metamaterial transmission array antenna. Its main purpose is to reduce the high sidelobe level problem caused by the large aperture phase quantization error due to the low phase state of the radiating element, which results in large angle scanning. By rationally designing the feed network, precise control of the element's radiated power can be achieved, bringing more possibilities to the design.

[0026] Compared with existing technologies, this design solves the problems of high cost and long component design cycle of traditional phased array antennas. Due to the use of a planar feed network, the overall profile of the antenna array is reduced compared to traditional reconfigurable reflective and reconfigurable transmission arrays. Simultaneously, a 2-bit phase-shifting strategy is employed, improving the antenna's aperture efficiency and scanning range. Furthermore, the introduction of spherical wave phase effectively reduces the antenna's sidelobes during large-angle scanning, extending the antenna array's scanning range. The designed low-profile, low-cost, low-sidelobe phased array antenna provides a new design approach for low-cost, large-angle scanning, and high-performance phased array antennas.

[0027] like Figure 4 As shown, the low-sidelobe phased array antenna based on reconfigurable radiating elements provided by the present invention includes a spherical wave generating device 19, a 2-bit reconfigurable radiating element 20, and a feeding network 21 arranged sequentially from top to bottom. The feeding network 21 feeds the 2-bit reconfigurable radiating element 20, and the radiated signal of the 2-bit reconfigurable radiating element 20 is radiated out as a spherical wave through the spherical wave generating device 19.

[0028] Specifically, the spherical wave generating device 19 can be realized by a lens or a metamaterial planar transmission array.

[0029] like Figure 3 As shown, the 2-bit reconfigurable radiating unit 20 includes a first PCB board 14, a second PCB board 15, and a third PCB board 16 arranged from top to bottom.

[0030] like Figure 1 As shown, a radiating component, a first power supply structure 12, a first PIN diode 1, and a second PIN diode 2 are provided on the front side of the first PCB board 14. The radiating component includes a first radiating patch 7 and a second radiating patch 8, which are symmetrically located on both sides of the first power supply structure 12. The first radiating patch 7 is connected to the first power supply structure 12 through the first PIN diode 1, and the second radiating patch 8 is connected to the first power supply structure 12 through the second PIN diode 2.

[0031] Specifically, the first radiating patch 7 and the second radiating patch 8 are rectangular structures.

[0032] Specifically, the first power supply structure 12 is a square structure.

[0033] like Figure 3 As shown, an intermediate floor layer 13 is provided between the first PCB board 14 and the second PCB board 15.

[0034] like Figure 1As shown, a phase adjustment component, a second power supply structure 22, a third power supply structure 23, a third PIN diode 3, a fourth PIN diode 4, a fifth PIN diode 5, and a sixth PIN diode 6 are provided on the front side of the third PCB board 16. The phase adjustment component includes a first phase delay line 10 and a second phase delay line 11. The first phase delay line 10 and the second phase delay line 11 are in the form of strip lines. The first phase delay line 10 is connected to the second power supply structure 22 through the fourth PIN diode 4 and to the third power supply structure 23 through the third PIN diode 3. The second phase delay line 11 is connected to the second power supply structure 22 through the sixth PIN diode 6 and to the third power supply structure 23 through the fifth PIN diode 5.

[0035] Specifically, the second power supply structure 22 and the third power supply structure 23 are symmetrically arranged and are both square structures.

[0036] like Figure 3 As shown, a bottom floor 17 is provided on the back of the third PCB board 16, the middle floor 13 is the antenna radiating unit reflective floor and the upper floor of the strip, and the bottom floor 17 is the lower floor of the strip.

[0037] like Figure 1-2 As shown, one end of the SMA power supply structure 9 is connected to a port of the power supply network 21, and the other end is connected to the third power supply structure 23. Metal vias 18 are provided at the positions of the second power supply structure 22 on the first PCB board 14 and the second PCB board 15 corresponding to the third PCB board 16, and the metal vias correspond to the first power supply structure 12 on the first PCB board 14, so as to transmit power to the first radiating patch 7 or the second radiating patch 8.

[0038] Based on the above antenna structure, this invention also provides a method for reconfigurable radiation pattern. By adjusting the switching of the first PIN diode 1, the second PIN diode 2, the third PIN diode 3, the fourth PIN diode 4, the fifth PIN diode 5, and the sixth PIN diode 6 in conjunction with the first phase delay line 10 and the second phase delay line 11, the radiation phase of the radiating element is adjusted, thereby achieving reconfigurable radiation pattern and enabling electrical scanning of the beam pointing. Specifically, the third PIN diode 3 and the fourth PIN diode 4 are simultaneously turned on or off; the fifth PIN diode 5 and the sixth PIN diode 6 are simultaneously turned on or off.

[0039] As shown in Table 1, 1# represents the first PIN diode 1, 2# represents the second PIN diode 2, 3# represents the third PIN diode 3, 4# represents the fourth PIN diode 4, 5# represents the fifth PIN diode 5, and 6# represents the sixth PIN diode 6; "1" indicates the on state, and "0" indicates the off state.

[0040] When the phase is 0°, it means that the first PIN diode 1 is on, the second PIN diode 2 is off, the third PIN diode 3 is on, the fourth PIN diode 4 is on, the fifth PIN diode 5 is off, and the sixth PIN diode 6 is off.

[0041] When the phase is 90°, it means that the first PIN diode 1 is on, the second PIN diode 2 is off, the third PIN diode 3 is off, the fourth PIN diode 4 is off, the fifth PIN diode 5 is on, and the sixth PIN diode 6 is on.

[0042] When the phase is 180°, it means that the first PIN diode 1 is off, the second PIN diode 2 is on, the third PIN diode 3 is on, the fourth PIN diode 4 is on, the fifth PIN diode 5 is off, and the sixth PIN diode 6 is off.

[0043] When the phase is 270°, it means that the first PIN diode 1 is off, the second PIN diode 2 is on, the third PIN diode 3 is off, the fourth PIN diode 4 is off, the fifth PIN diode 5 is on, and the sixth PIN diode 6 is on.

[0044] Table 1

[0045] Figure 5 The phase distribution of the spherical wave generated by the designed spherical wave generator is given. It can be seen that the phase of the spherical wave generated by the spherical wave generator changes uniformly from 0° to 90° from the center to the edge.

[0046] Figure 6 The four far-field radiation phase states of the designed 2-bit reconfigurable cell are given. It can be seen that according to the diode switching logic relationship listed in Table 1, the designed radiation cell presents four phase radiation states of 0, 90, 180 and 270.

[0047] Figure 7 According to Figure 6 The four phase states shown and Figure 5 The radiation pattern obtained by calculating the phase distribution generated by the spherical wave generator shown can be seen from the fact that the design of this invention achieves ±60° beam scanning and has low sidelobes when scanning at large angles.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A low sidelobe phased array antenna based on reconfigurable radiating elements, characterized in that, It includes a spherical wave generating device (19), a 2-bit reconfigurable radiation unit (20), and a power supply network (21) arranged from top to bottom; the power supply network (21) supplies power to the 2-bit reconfigurable radiation unit (20), and the radiation signal of the 2-bit reconfigurable radiation unit (20) is radiated out after passing through the spherical wave generating device (19); The spherical wave generating device (19) is realized by means of a lens or a metamaterial planar transmission array; The 2-bit reconfigurable radiating unit (20) includes a first PCB board (14), a second PCB board (15), and a third PCB board (16) arranged from top to bottom. The first PCB board (14) is provided with a radiating component and a first feeding structure (12). The third PCB board (16) is provided with a phase adjustment component, a second feeding structure (22), and a third feeding structure (23). The first feeding structure (12), the second feeding structure (22), and the third feeding structure (23) constitute the feeding component, which feeds the radiating component and adjusts the phase through the phase adjustment component. The radiating component includes a first radiating patch (7) and a second radiating patch (8). The first radiating patch (7) is connected to the first feeding structure (12) through a first PIN diode (1), and the second radiating patch (8) is connected to the first feeding structure (12) through a second PIN diode (2). The first radiating patch (7) and the second radiating patch (8) are symmetrically located on both sides of the first feeding structure (12); The phase adjustment component includes a first phase delay line (10) and a second phase delay line (11); the first phase delay line (10) is connected to the second feed structure (22) through a fourth PIN diode (4) and to the third feed structure (23) through a third PIN diode (3); the second phase delay line (11) is connected to the second feed structure (22) through a sixth PIN diode (6) and to the third feed structure (23) through a fifth PIN diode (5); The power supply signal is connected between the first PCB board (14) and the third PCB board (16) through a metal via. The metal via passes through the second PCB board (15), with the upper end connected to the first power supply structure (12) and the lower end connected to the second power supply structure (22). An intermediate floor layer (13) is provided between the first PCB board (14) and the second PCB board (15). A bottom floor (17) is provided on the back of the third PCB board (16), the middle floor (13) is the antenna radiating element reflector floor and the strip upper floor, and the bottom floor (17) is the strip lower lower floor; The 2-bit reconfigurable radiating unit (20) also includes an SMA feed structure (9), one end of which is connected to a port of the feed network (21), and the other end is connected to a third feed structure (23).

2. A method for reconfiguring the radiation pattern using a low-sidelobe phased array antenna based on reconfigurable radiating elements, as described in claim 1, characterized in that... By adjusting the switches of the first PIN diode (1), the second PIN diode (2), the third PIN diode (3), the fourth PIN diode (4), the fifth PIN diode (5), and the sixth PIN diode (6) in conjunction with the first phase delay line (10) and the second phase delay line (11), the radiation phase of the radiation unit can be adjusted to achieve reconfigurable radiation pattern, thereby realizing beam pointing electrical scanning.

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