Fabrication method of multifunctional double-sided reconfigurable transmission and reflection array

Abstract

This invention proposes a method for fabricating a multifunctional dual-sided reconfigurable transmission-reflection array, which includes a reflection array, a transmission array, and a transmission-reflection array. It can achieve time-division and simultaneous bidirectional beam scanning. A reconfigurable transmission-reflection array element design method is proposed, which can achieve 1-bit phase control of the transmitted and reflected waves. At the same time, the transmission and reflection elements are sparsely optimized and arranged. The particle swarm optimization algorithm is used to reduce sidelobes and improve gain, and the simultaneous bidirectional beam scanning function is achieved. The antenna array adopts an air-feed method. Because it does not require a complex feeding network and adopts an integrated design of phase shift and radiation structure, it replaces the expensive phase shifter and becomes one of the alternative solutions for the next generation of low-cost phased arrays.

Description

Technical Field

[0001] This invention belongs to the field of electronic communication technology, and specifically relates to a method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array. Background Technology

[0002] A multifunctional bifacial reconfigurable transmission-reflection array has been proposed, which integrates a reflection array, a transmission array, and a transmission-reflection array, enabling time-division and simultaneous bidirectional beam scanning. The transmission-reflection unit structure includes a pair of orthogonal grating structures, a reconfigurable metallic resonator layer, and a DC bias line layer, allowing for 1-bit phase control of both transmitted and reflected waves. The reconfigurable transmission-reflection array consists of 256 elements, employing 1-bit phase quantization encoding for time-division beam scanning. Sparse optimization of the transmission and reflection elements and a particle swarm optimization algorithm are used to reduce sidelobes and increase gain, thereby achieving simultaneous bidirectional beam scanning at a test frequency of 9.5 GHz.

[0003] Existing bidirectional beamforming methods primarily utilize dual-sided phased arrays, such as Russia's Big Bird radar and the PLA's S-300PMU1 missile system's 64N6E detection radar. Their architecture includes two horn antenna feeds and dual-sided antenna apertures, achieving 3D beam scanning through mechanical rotation. This architecture typically requires two antenna systems, including two horn antenna feeds and dual-sided antenna apertures, undoubtedly increasing system costs. Furthermore, the mechanical rotation for 3D beam scanning increases antenna response time. Air-fed antenna arrays, due to their elimination of complex feed networks and integrated phase-shifting and radiation structures, replace expensive phase shifters, making them a viable option for next-generation low-cost phased arrays. Existing methods for reconfigurable air-fed antenna arrays mainly include three types, such as... Figure 1 As shown, there are reflective arrays, transmission arrays, and transmission-reflective arrays. They typically include a feed antenna and an aperture with phase modulation. By integrating liquid crystals, MEMS, varactor diodes, PIN diodes, etc., into the aperture, the phase of the elements within the aperture can be flexibly controlled, thereby achieving dynamic beam control. A single transmission array or reflective array can only achieve beam scanning in half-space and cannot achieve functional switching and simultaneous scanning of transmitted and reflected beams.

[0004] A low-loss transmission array element based on a polarization conversion mechanism and a double-layer orthogonal grating achieves beam scanning by modulating the phase of the polarization-converted wave. The feed position is selected by calculating the optimal value of balancing spillover power and illumination power. The phase compensation value of the element is calculated according to the phase compensation principle, then quantized, and the diode state is encoded. A sparse optimization arrangement of transmission and reflection elements is employed, and a particle swarm optimization algorithm is used to reduce sidelobes and increase gain, enabling simultaneous bidirectional beam scanning.

[0005] Air-fed antenna arrays, due to their elimination of complex feeding networks and integrated phase-shifting and radiating structure design, have replaced expensive phase shifters, making them one of the alternatives for next-generation low-cost phased arrays. Currently, there are three main types of reconfigurable air-fed antenna arrays: reflective arrays, transmission arrays, and transmission-reflection arrays. These typically include a feed antenna and an aperture with phase modulation capabilities. By integrating liquid crystals, MEMS, varactor diodes, PIN diodes, etc., into the aperture, the phase of the elements within the aperture can be flexibly controlled, thereby achieving dynamic beamforming.

[0006] Dual-sided phased arrays can achieve bidirectional beamforming. Examples include Russia's Big Bird radar and the PLA's S-300PMU1 missile system's 64N6E detection radar. Their architecture includes two horn antenna feeds and a dual-sided antenna aperture, achieving 3D beam scanning through mechanical rotation. This architecture typically requires two antenna systems.

[0007] To further reduce costs, the concept of a transmission-reflection array has been proposed. It typically includes a feed antenna and an aperture capable of modulating both reflected and transmitted waves. Transmission-reflection arrays can be categorized based on their bidirectional beam coverage mode: time-division bidirectional beaming and simultaneous bidirectional beaming. In simultaneous bidirectional beaming mode, reflected and transmitted beams are generated simultaneously and have independent beam scanning. In time-division bidirectional beaming mode, a single reflected or transmitted beam is generated in a time-division manner, with the beam switching time being the response time of the FPGA or other control circuitry. Summary of the Invention

[0008] The present invention aims to solve the technical problems existing in the prior art, and the purpose of the present invention is to provide a multifunctional double-sided reconfigurable transmission and reflection array.

[0009] To achieve the above objectives, the present invention is implemented through the following scheme: a method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array, comprising the following steps:

[0010] Step 1: Design a reconfigurable transmission / reflection array unit. The unit structure includes a pair of orthogonal grating structures, a reconfigurable metal resonant layer, and a DC bias line layer. F4B dielectric is used. The second and third dielectric layers are bonded together using a Rogers RO4450F adhesive layer. The metal resonant layer consists of a central reconfigurable layer, an upper grating layer, and a lower grating layer. The central patch and edge structure are connected via two diodes. A vertical line is added to the center. After the units form a periodic array, the vertical line is connected to the DC "ground". Holes are drilled in the first dielectric layer to accommodate the diodes. A MACOM MADP-000907-14020 PIN diode is selected as the controller. To achieve independent control of the diodes by the DC bias voltage, a bent line is used as an RF and DC isolation component, connected to the bias layer through a metallized via passing through the bottom grating. To reduce the impact of the bias line on transmission characteristics, the direction of the bias line is the same as the direction of the lower grating. Since each unit integrates two diodes, the diodes should have four states: "00" OFF / OFF, "01", etc. The OFF / ON, “10” ON / OFF, and “11” ON / ON states were simulated using the commercial simulation software CST.

[0011] Step 2: Fabricate the array. The diodes are integrated into the array and connected to the FPGA via a bias line. A horn antenna is used as the feed source, with a pattern factor of qf=3.5 at 9.5 GHz. The feed source position z=-140 is selected by calculating the optimal value of balancing the overflow power and the illumination power.

[0012] Step three: Calculate the phase compensation value of the unit based on the phase compensation principle, then quantize and encode the diode state. For an empty-fed antenna array, in order to achieve... For a pencil beam in the (θ0, φ0) direction, the phase of each element should be set as follows:

[0013] (1)

[0014] in, and Let be the position vector of the feed source and the position vector of the (m,n)th element, respectively, and k be the wavenumber in free space. It is the phase constant, usually an optimized value; φm,n needs to be converted to - and In this design, since 1-bit phase quantization is used, the quantization rule is as follows:

[0015] (2)

[0016] If a pencil-shaped beam (transmission array function) is formed in the upper half-space, the encoding state of each unit should be:

[0017] (3)

[0018] If a pencil-shaped beam (reflection array function) is formed in the lower half-space, the encoding state of each unit should be:

[0019] (4)

[0020] The FPGA circuit is used to control the state of 512 diodes, and the entire test is completed in a near-field test system.

[0021] Step 4: Use a near-field testing system to perform transmission mode testing and reflection mode testing on the multifunctional double-sided reconfigurable transmission and reflection array; the coded distribution on the aperture can be calculated according to formulas (1)-(3).

[0022] Step 5 involves sparsely optimizing the arrangement of transmission and reflection elements, employing a particle swarm optimization algorithm to reduce sidelobes and increase gain, and simultaneously implementing bidirectional beam scanning functionality. Two methods exist to achieve a single aperture with both transmission and reflection beams. The first method is a geometric arrangement where the entire aperture is divided into two sub-arrays, splitting the energy from the feed onto the array. The left-hand elements operate in reflection mode, while the right-hand elements operate in transmission mode. The second method is random position optimization for transmission and reflection, using a sparse array approach to decompose the entire array into a mode where transmission and reflection modes coexist. That is, some elements of the transmission-reflection array operate in transmission mode, while the remaining elements operate in reflection mode. The entire transmission-reflection array is considered as a sparse transmission array and a sparse reflection array. In this case, the encoding on the array surface should include four states: "10", "01", "11", and "00".

[0023] The beneficial effects of this invention are as follows: This invention proposes a multifunctional bifacial reconfigurable transmission-reflection array, which includes a reflection array, a transmission array, and a transmission-reflection array. It can achieve time-division and simultaneous bidirectional beam scanning. In simultaneous bidirectional beam mode, reflected and transmitted beams are generated simultaneously and have independent beam scanning capabilities. In time-division bidirectional beam mode, a single reflected or transmitted beam is generated in a time-division manner. This multifunctional bifacial reconfigurable transmission-reflection array includes only one feed antenna and an aperture with the function of controlling reflected and transmitted waves. Due to the reduction in the number of feed antennas and aperture control devices, the manufacturing cost is greatly reduced. Furthermore, by adopting an electronic control method, the beam switching time is the response time of an FPGA or other control circuit, which is significantly reduced compared to methods that achieve 3D beam scanning through mechanical rotation. Attached Figure Description

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0025] Figure 1 The specific structure of the metal resonant layer in this application is shown in the following diagrams: (a) Overall structure diagram; (b) Central reconfigurable layer; (c) Upper grating layer; (d) Lower grating layer.

[0026] Figure 2 The present application embodiment shows the simulation performance of four state units under vertical incidence. (a) and (b) are the reflection amplitude and phase of states "10" and "01" respectively, and (c) and (d) are the reflection amplitude and phase of states "11" and "00" respectively.

[0027] Figure 3 The transmitted beam pattern tested in the embodiments of this application is the beam of the xoz plane (a) and yoz plane.

[0028] The beam pattern of the reflected beams is scanned and tested (c) xoz plane (d) yoz plane.

[0029] Figure 4 This is the geometric half-arrangement in the test transmission and reflection bidirectional beam implementation method of the embodiments of this application;

[0030] Figure 5 This is a schematic diagram illustrating the optimized layout and coding process implemented in this application;

[0031] Figure 6 The far-field radiation patterns of the test performed on the yoz plane in this application are: (a) θT0 = 0°, θR0 = 170°, (b) θT0 = 0°, θR0 = 150°, (c) θT0 = -30°, θR0 = 140°, (d) θT0 = -20°, θR0 = 200°;

[0032] Figure 7 This is the boundary function of the transmission and reflection two-sided radiation pattern implemented in this application;

[0033] Figure 8 This application implements transmission and reflection in both directions. Figure 2 D Boundary function (a) Upper boundary of transmission (b) Lower boundary of transmission (c) Upper boundary of reflection (d) Lower boundary of reflection;

[0034] Figure 9 This refers to the random arrangement in the test transmission and reflection bidirectional beam implementation method of the embodiments of this application. Detailed Implementation

[0035] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified, the experimental methods used in the following experimental examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available reagents and materials.

[0036] This invention provides a method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array, which consists of the following steps:

[0037] Step 1: Design a reconfigurable transmission / reflection array unit. The unit structure includes a pair of orthogonal grating structures, a reconfigurable metal resonant layer, and a DC bias line layer. F4B dielectric is used. The second and third dielectric layers are bonded together using a Rogers RO4450F adhesive layer. The metal resonant layer consists of a central reconfigurable layer, an upper grating layer, and a lower grating layer. The central patch and edge structure are connected via two diodes. A vertical line is added to the center. After the units form a periodic array, the vertical line is connected to the DC "ground". A hole is drilled in the first dielectric layer to accommodate the diodes. A MACOM MADP-000907-14020 PIN diode is selected as the controller. To achieve independent control of the diodes by the DC bias voltage, a bent line is used as an RF and DC isolation component, connected to the bias layer through a metallized via passing through the lower grating. To reduce the impact of the bias line on the transmission characteristics, the direction of the bias line is the same as the direction of the lower grating. Since each unit integrates two diodes, the diodes should have four states: "00" OFF / OFF, "01" OFF, "02" OFF, "03" OFF, "04" OFF, "05" OFF, "06" OFF, "07" OFF, "08" OFF, "09" OFF, "01" OFF, "01" OFF, "01" OFF, "02 ... OFF / ON, “10” ON / OFF, and “11” ON / ON – the unit under these four states was simulated using the commercial simulation software CST. (See attached image.) Figure 1 and attached Figure 2 As shown.

[0038] Step 2: Fabricate the array. The diodes are integrated into the array and connected to the FPGA via a bias line. A horn antenna is used as the feed source, with a pattern factor of qf=3.5 at 9.5 GHz. The feed source position z=-140 is selected by calculating the optimal value of balancing the overflow power and the illumination power.

[0039] Step three: Calculate the phase compensation value of the unit based on the phase compensation principle, then quantize and encode the diode state. For an empty-fed antenna array, in order to achieve... For a pencil beam in the (θ0, φ0) direction, the phase of each element should be set as follows:

[0040] (1)

[0041] in, and Let be the position vector of the feed source and the position vector of the (m,n)th element, respectively, and k be the wavenumber in free space. It is the phase constant, usually an optimized value; φm,n needs to be converted to - and In this design, since 1-bit phase quantization is used, the quantization rule is as follows:

[0042] (2)

[0043] If a pencil-shaped beam (transmission array function) is formed in the upper half-space, the encoding state of each unit should be:

[0044] (3)

[0045] If a pencil-shaped beam (reflection array function) is formed in the lower half-space, the encoding state of each unit should be:

[0046] (4)

[0047] The FPGA circuit is used to control the state of 512 diodes, and the entire test is completed in a near-field test system.

[0048] Step four: Use a near-field testing system to perform transmission mode and reflection mode tests on the multifunctional double-sided reconfigurable transmission and reflection array; the coded distribution on the aperture can be calculated according to formulas (1)-(3). (See attached...) Figure 3 As shown.

[0049] Step 5 involves sparsely optimizing the arrangement of transmission and reflection elements, using a particle swarm optimization algorithm to reduce sidelobes and increase gain, and simultaneously implementing bidirectional beam scanning functionality. Two methods exist to achieve a single aperture with both transmission and reflection beams. The first method is a geometric arrangement where the entire aperture is divided into two sub-arrays. The energy from the feed to the array is split in two, with the left element operating in reflection mode and the right element operating in transmission mode. The second method is random position optimization for transmission and reflection, using a sparse array approach to decompose the entire array into a mode where transmission and reflection modes coexist. That is, some elements of the transmission-reflection array operate in transmission mode, while the remaining elements operate in reflection mode. The entire transmission-reflection array is considered as a sparse transmission array and a sparse reflection array. In this case, the encoding on the array surface should include four states: "10", "01", "11", and "00". (See attached image) Figure 4 and attached Figure 9 As shown.

[0050] Since the positions of the elements are fixed, only the encoding method of each element needs optimization. Once the encoding of the array surface is determined, the far field of the entire transmission and reflection array can be quickly calculated using array theory. To quickly optimize the encoding on the array surface, a particle swarm optimization algorithm is used to optimize the bidirectional beam performance. Because the entire aperture contains 256 elements, each with 4 states, the entire solution space includes 4256 cases. (See attached...) Figure 5 and attached Figure 6 As shown.

[0051] Initialize 256 equally likely variables A (0 / 1). If Amn = 1, it means the (m, n)th element is operating in reflection mode, and Amn = 0, it means the element is operating in transmission mode. Therefore, the excitation of the elements in the reflection array is: Amn, the excitation of the transmission array elements is: .

[0052] Determine the beam direction of transmission and reflection, and generate two phase constants ( and ), its range is [0 2 The quantized phases of transmission and reflection can be obtained using quantization formulas (1) and (2). and Therefore, the total quantization phase on the array surface is: .

[0053] pass and Calculate the far-field radiation pattern of the lower half-space by... and Calculate the far-field radiation pattern of the upper half-space. It is worth noting that, since only one polarization dominates in each half-space, the influence of polarization is ignored in the far-field calculation to simplify the calculation.

[0054] To achieve bidirectional beamforming, the pattern boundary function needs to be configured across the entire spectrum to optimize for the lowest sidelobe level and maximum gain. The pattern boundary function typically requires defining the "upper boundary" and "lower boundary" of the desired pattern.

[0055] Because the pattern boundary function is set across the entire space, Figure 8 The transmission and reflection directions are given. Figure 2 The boundary function D has a circular profile. The purpose of the optimization is to constrain the optimized transmission and reflection patterns within the upper and lower boundary functions, and its fitness function is set as follows: ;

[0056] in, and The distribution represents the upper and lower boundaries of the far-field radiation pattern. E is the far-field radiation pattern of the array. The first term in 6 calculates the difference between the main lobe level and the lower boundary function in the main lobe region, used to evaluate main lobe performance. The second term calculates the difference between the sidelobes and the upper boundary function in all other regions, used to evaluate sidelobe performance. w1 and w2 are the weights of these two terms, set in this optimization as follows: w1 = 2, w2 = 1. The above formula evaluates every point in the visible space.

[0057] Call the PSO optimizer to optimize A. , (A total of 258 unknowns), with a particle population size of 200. In optimization, a smaller fitness function value results in an optimized array pattern that more closely approximates the expected pattern. A contraction factor is used in the particle motion equations to accelerate the convergence of the optimization function.

[0058] Once the particle swarm optimization algorithm meets the convergence condition, steps three and four are performed to obtain the transmission and reflection mode distribution and the encoded distribution. The optimized dual-beam pattern is then calculated.

[0059] It is worth noting that the optimization time described above depends on the resolution of the far-field pattern and the number of particles. In this chapter's optimization, the far-field pattern interval is set to 1 degree, and the particle population size is 200. (See attached...) Figure 7 and attached Figure 8 As shown.

[0060] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific structures and / or characteristics in the solutions are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array, characterized in that, The fabrication method of the multifunctional double-sided reconfigurable transmission and reflection array consists of the following steps: Step 1: Design reconfigurable transmission and reflection array elements and arrange the elements into a periodic array; Step two: Fabricate the array, integrate the diodes into the array, and connect them to the FPGA via bias lines; Step 3: Calculate the phase compensation value of the unit according to the phase compensation principle, then quantize and encode the diode state; Step 4: Use a near-field testing system to perform transmission mode and reflection mode tests on the multifunctional double-sided reconfigurable transmission and reflection array; Step 5 involves sparsely optimizing the arrangement of transmission and reflection elements, using a particle swarm optimization algorithm to reduce sidelobes and increase gain, while simultaneously testing bidirectional beam scanning functionality. The optimized arrangement has two methods: the first is a geometric arrangement where the entire aperture is divided into two sub-arrays, splitting the energy from the feed to the array surface in two. The left part of the array operates in reflection mode, while the right part operates in transmission mode. The second method is random position optimization for transmission and reflection, using a sparse array to decompose the entire array surface into a mode where transmission and reflection modes coexist. Some elements of the transmission and reflection array operate in transmission mode, while the remaining elements operate in reflection mode. The entire transmission and reflection array can be viewed as a sparse transmission array and a sparse reflection array. In this case, the encoding on the array surface should include four states: "10", "01", "11", and "00".

2. The method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array according to claim 1, characterized in that: The reconfigurable transmission-reflection array unit described in step one includes an upper grating layer, a reconfigurable metal resonant layer, a DC bias line layer, and a lower grating layer. The dielectric material used is F4B. To achieve independent control of the diodes by the DC bias voltage, a bent line is used as an isolation component between radio frequency and DC. It is connected to the bias line layer through a metallized via. To reduce the influence of the bias line on the transmission characteristics, the direction of the bias line is the same as the direction of the lower grating. Each unit integrates two diodes, with four states: "00" OFF / OFF, "01" OFF / ON, "10" ON / OFF, and "11" ON / ON. The unit in the four states is simulated using the commercial simulation software CST.

3. The method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array according to claim 1, characterized in that: The array described in step two uses a horn antenna as the feed source, and its pattern factor is qf=3.5 at 9.5 GHz. By calculating the optimal value of balancing the overflow power and the illumination power, the coordinates of the feed source phase center are selected to be located at (0,0,-140).

4. The method for fabricating a multifunctional double-sided reconfigurable transmission and reflection array according to claim 1, characterized in that: The phase set for each unit in step three is as follows: ; in, and These are the position vectors of the feed source and the (m,n)th element, respectively. It refers to the direction of the beam. It is the wavenumber of free space. It is the phase constant. To be converted and In this unit design, 1-bit phase quantization is used, and its quantization rule is as follows: ; If a pencil-shaped beam is formed in the upper half-space to achieve the function of a transmission array, the encoding state of each unit should be: ; If a pencil-shaped beam is formed in the lower half-space to achieve the function of a reflection array, the coding state of each unit should be: ; The FPGA circuit can be used to control the state of 512 diodes, and the entire test is completed in a near-field test system.

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