A Method for Expanding the Angular Target Range of Echo Signals Based on Reconfigurable Metasurfaces

Abstract

The present invention discloses a method for expanding the angular target range of echo signals based on a reconfigurable metasurface, belonging to the field of hardware-in-the-loop simulation systems. The method of the present invention adds a reconfigurable metasurface on the basis of the existing hardware-in-the-loop simulation system. By feeding the reconfigurable metasurface through a feed antenna, and utilizing the characteristic that the periodic structure of the metasurface can shape the electromagnetic wave beam, through the combination of the feed antenna and the metasurface control technology, a larger angular target range of echo signals can be achieved without changing the existing radio frequency hardware-in-the-loop simulation system.

Description

Technical Field

[0001] The present invention belongs to the field of hardware-in-the-loop simulation systems, and particularly relates to a method for expanding the angular target range of echo signals based on a reconfigurable metasurface. Background Art

[0002] With the rapid development of computer technology, electronic technology, simulation theory, etc., hardware-in-the-loop simulation has key advantages such as good flexibility, high repeatability, and high fidelity, and plays an irreplaceable role in improving the development cycle of system equipment, reducing development costs, and improving equipment performance. In the acquisition of electromagnetic characteristics of radar targets, using hardware-in-the-loop simulation to replace field tests can eliminate the influence of adverse factors in the field environment and obtain more accurate target electromagnetic characteristics, which has received close attention and extensive research from domestic and foreign research institutions.

[0003] In an array-type hardware-in-the-loop simulation system, the position simulation of the target is achieved by selecting different antennas in the antenna array to transmit echo signals. In the hardware-in-the-loop simulation system, once the positions of the transmitting antenna array and the turntable receiving antenna are established, the angular target range of the echo signals that can be tested is determined. If a wider angular target range of echo signals is required, the array or the anechoic chamber needs to be updated. With the continuous improvement of the requirements for hardware-in-the-loop simulation technology, the demand for a larger angular target range of echo signals has become increasingly urgent. How to obtain a larger angular target range of echo signals based on the existing hardware-in-the-loop simulation system has become an urgent problem to be solved. Adopting new technologies can effectively expand the angular target range of echo signals on the existing hardware-in-the-loop simulation system.

[0004] Metasurfaces can achieve the confinement and regulation of electromagnetic waves at the sub-wavelength scale through specific unit structures and novel physical properties. At the same time, relying on its own advantages such as low loss, low profile, easy design and fabrication, etc., it has received extensive attention from the scientific community and the industrial community. In the past few decades, the development of metasurfaces has made great progress. By loading tunable materials such as electronic switches, optoelectronic switches, and tunable materials on the metasurface, the metasurface has the ability to dynamically adjust electromagnetic waves. Summary of the Invention

[0005] Aiming at the limitation that the field of view angle of the array in the traditional radio frequency hardware-in-the-loop simulation system depends on the spatial layout of the antennas, the present invention provides a method for expanding the angular target range of echo signals based on a reconfigurable metasurface. Based on the existing hardware-in-the-loop simulation system, this method uses a feed antenna to irradiate the reconfigurable metasurface, and utilizes the characteristic that the periodic structure of the metasurface can shape the electromagnetic wave beam. By combining the feed antenna with the metasurface regulation technology, a larger angular target range of echo signals can be achieved without changing the existing radio frequency hardware-in-the-loop simulation system.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A method for expanding the angular target range of echo signals based on a reconfigurable metasurface, characterized by comprising the following steps:

[0008] S1. Establish a radio frequency hardware-in-the-loop simulation system, which includes a turntable receiving antenna, a feed antenna, and a reconfigurable metasurface antenna array. A rectangular coordinate system is established with the turntable receiving antenna as the origin (0, 0). Given that the position of the feed antenna is (x0, y0), the central position of the reconfigurable metasurface antenna array is set as (x1, y1), and x1 > x0, y1 < y0; define θ as the angular target of the echo signal that can be achieved by the antenna array of the original hardware-in-the-loop simulation system, θ1 is the angular target of the echo signal after the electromagnetic wave radiated by the feed antenna is reflected by the reconfigurable metasurface antenna array, θ r is the reflection angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array, θ i is the incident angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array, and L represents the distance between the receiving antenna and the feed antenna.

[0009] S2. According to the generalized Snell's law: Obtain the relationship between θ r , θ i and where represents the phase gradient between adjacent units, φ represents the phase difference between adjacent metasurface units in the reconfigurable metasurface antenna array, x represents the size of the metasurface unit, k0 represents the free space wave number, k0 = 2π / λ0, and λ0 is the wavelength.

[0010] S3. Construct the position relationship between x1 and y1 of the reconfigurable metasurface antenna array through the angular target θ1 of the echo signal, where the reflection angle θ r = 90° - θ1, y0 = Lcosθ, x0 = Lsinθ, x1 = y1tanθ r .

[0011] S4. Combine S2 and S3 to obtain the relationship between the phase difference φ between adjacent metasurface units in the reconfigurable metasurface antenna array and θ1, thereby obtaining the position layout of the feed antenna, the reconfigurable metasurface antenna array, and the turntable receiving antenna, and further realizing the expansion of the angular target range of the echo signal of the radio frequency hardware-in-the-loop simulation system.

[0012] In the present invention, the feed antenna irradiates the reconfigurable metasurface antenna array, utilizes the ability of the reconfigurable metasurface array to regulate the reflected wave, and constructs the spatial position relationship among the turntable receiving antenna, the feed antenna, and the reconfigurable metasurface array antenna according to the angular target θ1 of the echo signal. On the basis of the existing hardware-in-the-loop simulation system, the effective expansion of the angular target range of the echo signal can be achieved by adding the reconfigurable metasurface array antenna. Description of the Drawings

[0013] Figure 1 Schematic diagram of beam deflection of a reconfigurable metasurface electromagnetic modulation antenna array with incident feed antenna

[0014] Figure 2 Schematic diagram of the generalized Snell's reflection law at the incident position of the reconfigurable metasurface

[0015] Figure 3 Relative position relationship diagram between the reconfigurable metasurface electromagnetic modulation antenna array and the feed antenna at normal incidence

[0016] Figure 4 Relationship diagram between the incident angle of the feed antenna and the phase difference of the reconfigurable metasurface antenna array

[0017] Explanation of the reference numerals in the drawings: 1 represents the turntable receiving antenna, 2 represents the feed antenna; 3 represents the reconfigurable metasurface antenna array Detailed Implementation Manner

[0018] In order to better understand the technical solution of the present invention, the following content will further describe the implementation manner of the present invention in conjunction with the drawings

[0019] The method for expanding the angular target range of the echo signal based on the reconfigurable metasurface in this embodiment includes the following steps

[0020] S1 Figure 1 This is a schematic diagram of realizing beam deflection of the feed antenna incident on the reconfigurable metasurface antenna array of the present invention. A rectangular coordinate system is established with the turntable receiving antenna as the origin (0,0). Given that the position of the feed antenna is (x0, y0) and the center position of the reconfigurable metasurface antenna array is (x1, y1), θ is the angular target of the echo signal that the antenna array of the original semi-physical simulation system can achieve, θ1 is the angular target of the echo signal after the electromagnetic wave radiated by the feed antenna is reflected by the reconfigurable metasurface antenna array, θ r is the reflection angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array, and θ i is the incident angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array

[0021] S2 Figure 2 This is a schematic diagram of the generalized Snell's reflection law of the present invention. θ i is the incident angle, and θ r is the reflection angle. There are two media with the x-axis as the interface in the xoz plane. Assume that the incident light starts from point A, and the optical paths ABD and ACD are infinitely close. Therefore, the light can generate exactly the same phase gradient through the two optical paths, and the phase difference is 0°. Draw BB1⊥AC through B and CC1⊥BD through C. It can be known that the phase accumulations of the two optical paths are respectively

[0022]

[0023]

[0024] Since the distance BC is extremely small, and BB1⊥AC, CC1⊥BD, thus let AB≈AB1, CD≈C1D, then from the equality of equations (1) and (2), it can be deduced that:

[0025]

[0026] Let BC = dx, then B1C = k0η i sinθ i dx. And CC1⊥BD, assuming ∠DCC1 = 90°, then ∠BCC1 = ∠DCE = θ r , thus BC1 = k0η i sinθ r dx, where η i represents the refractive index of the medium where the feed antenna is located. Substituting it into the above equation (3), we get:

[0027] k0η i sinθ r dx + Φ = k0η i sinθ i dx + Φ + dΦ (4)

[0028] After arranging equation (4) and eliminating the same terms, the following generalized Snell's reflection law can be obtained:

[0029]

[0030] This equation indicates that the phase gradient introduced by the structural unit on the interface of the reconfigurable metasurface antenna array can achieve the reflection of electromagnetic waves. Where φ is a phase mutation introduced on the interface, that is, the phase difference between adjacent units, k0 is the free-space wave number, k0 = 2π / λ0, and λ0 is the wavelength.

[0031] S3: Combining Figure 1 with the layout of the array antenna system, when the feed antenna irradiates the reconfigurable metasurface antenna array, by controlling the reflected beam of the reconfigurable metasurface antenna array, the receiving antenna receives the signal at the angle θ1 with respect to the y-axis, that is, the echo signal angular target is θ1. Where the reflection angle θ r = 90° - θ1, y0 = Lcosθ, x0 = Lsinθ, x1 = y1tanθ r . Figure 3It shows the positional relationship between the corresponding reconfigurable metasurface antenna arrays x1 and y1 when the echo signal angular target θ1 takes 22°, 25°, 30°, 35°, 40°, and 45° respectively. It can be seen from the figure that the two are linearly related, and satisfying this positional relationship can achieve an echo signal angular target greater than 20°.

[0032] S4: When satisfying Figure 3 the positional relationship of the reconfigurable metasurface electromagnetic modulation antenna in i for different echo signal angular targets θ1, the relationship between the incident angle θ of the feed antenna Figure 4 and the phase difference φ between adjacent units at the incident position of the reconfigurable metasurface antenna array is as Figure 4 shown. It can be seen from Figure 3 under the condition of the antenna system positional relationship that satisfies

[0033] , by adjusting the phase difference φ between adjacent units at the incident position of the corresponding reconfigurable metasurface, an echo signal angular target greater than 20° can be achieved.

[0033] S5: When the feed antenna is vertically incident on the metasurface, that is, when the incident angle θi of the feed antenna i = 0°, when the echo signal angular target θ1 = 30° is required, then the reflection angle θ of the reconfigurable metasurface r = 60°. According to the generalized Snell's reflection law, when the phase difference Δφ between adjacent units at the incident position of the reconfigurable metasurface is calculated to be 162°, an echo signal angular target of 30° can be achieved.

[0034] The above embodiments illustrate that the present invention provides a method for expanding the range of echo signal angular targets based on reconfigurable metasurfaces for the limitation that the array field of view angle in traditional radio frequency hardware-in-the-loop simulation systems depends on the spatial layout of antennas. Based on the existing hardware-in-the-loop simulation system, by combining the feed antenna and metasurface modulation technology, an echo signal angular target greater than 20° is achieved.

Claims

1. A method for expanding the angular target range of echo signals based on a reconfigurable metasurface, characterized in that, Including the following steps: S1. Establish a radio frequency hardware-in-the-loop simulation system, which includes a turntable receiving antenna, a feed antenna, and a reconfigurable metasurface antenna array. A rectangular coordinate system is established with the turntable receiving antenna as the origin (0, 0). Given that the position of the feed antenna is (x0, y0), the center position of the reconfigurable metasurface antenna array is set as (x1, y1), and x1 > x0, y1 < y0. Define θ as the echo signal angular target that can be achieved by the antenna array of the original hardware-in-the-loop simulation system, θ1 as the echo signal angular target after the electromagnetic wave radiated by the feed antenna is reflected by the reconfigurable metasurface antenna array, θ r is the reflection angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array, θ i is the incident angle of the electromagnetic wave radiated by the feed antenna at the reconfigurable metasurface antenna array, and L represents the distance between the receiving antenna and the feed antenna; S2. According to the generalized Snell's law: Obtain the relationship between θ r , θ i and , where represents the phase gradient between adjacent units, φ represents the phase difference between adjacent metasurface units in the reconfigurable metasurface antenna array, x represents the size of the metasurface unit, k0 represents the free-space wavenumber, k0 = 2π / λ0, and λ0 is the wavelength; S3. Construct the positional relationship between the reconfigurable metasurface antenna arrays x1 and y1 through the echo signal angular target θ1, where the reflection angle θ r = 90° - θ1, y0 = Lcosθ, x0 = Lsinθ, x1 = y1tanθ r ; S4. Combining S2 and S3, obtain the relationship between the phase difference φ between adjacent metasurface units in the reconfigurable metasurface antenna array and θ1, so as to obtain the position layout of the feed antenna, the reconfigurable metasurface antenna array, and the turntable receiving antenna, and further achieve the expansion of the echo signal angular target range of the radio frequency hardware-in-the-loop simulation system.

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