A Modular All-Metal Superlens Design Method

Abstract

This invention discloses a modular all-metal superlens design method, relating to the field of metamaterial lens design. The method includes: first, determining the operating frequency and desired focal position of the modular all-metal superlens; designing all-metal superlens units based on the operating frequency to achieve a phase control range exceeding 360° for the incident wave and a transmission amplitude exceeding -3dB; then, designing the phase arrangement of the superlens based on the desired focal position and operating frequency; quantizing the phase of the all-metal superlens with a 10° phase step based on the energy error, and modularizing each superlens unit; and reassembling the modularized superlens units into superlenses with different phase arrangements to form a modular all-metal superlens with adjustable energy and focal point. This invention enables modular all-metal superlenses, achieving adjustable energy and focal point without increasing cost, thus improving the freedom of superlens design.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metamaterial lens design, in particular to a modular full-metal superlens design method. BACKGROUND

[0002] The metamaterial lens is a two-dimensional planar lens structure, which is made of a super surface (a planar two-dimensional metamaterial with sub-wavelength thickness) focusing light. It is known as one of the top ten emerging technologies in 2019. This new type of metamaterial lens is called superlens.

[0003] The superlens based on near-field focusing has a wide range of applications in radar imaging, medicine and wireless energy transmission. In the process of radar imaging, because the signals of electromagnetic waves from different targets are different when passing through the converging lens to the receiving antenna, the image of the target can be formed. In medical treatment, the superlens can focus electromagnetic beams, which has the advantages of good directivity, high thermal efficiency, and high microwave hyperthermia gain.

[0004] However, the existing superlens generally uses PCB technology based on dielectric substrate for processing, which cannot work under high temperature, high pressure and high mechanical strength. For example, in the field of aerospace, the equipment usually needs to be used at a temperature of hundreds of meters. In this case, the metamaterial medium substrate will deform and melt. Moreover, when the energy focus of the superlens changes, it is generally necessary to replate and produce, which is very expensive.

[0005] Therefore, it is particularly important to enhance the high-temperature resistance of the superlens and reduce the manufacturing cost of the superlens. SUMMARY

[0006] The purpose of the embodiment of the present application is to provide a modular full-metal superlens design method to solve the problems of existing superlenses that are not resistant to high temperature and have high manufacturing cost.

[0007] To achieve the above purpose, the embodiment of the present application provides a modular full-metal superlens design method, comprising:

[0008] S1, according to the actual application scene, determine the working frequency of the modular full-metal superlens, and preset the expected focus position f of the energy convergence z ;

[0009] S2, according to the working frequency determined in step S1, design a full-metal superlens unit and perform modular modeling, limit the size and thickness of the structure, and realize the regulation range of the incident wave phase exceeding 360°, and the transmission amplitude exceeds-3dB;

[0010] S3, according to the expected focus position preset in step S1, the phase arrangement mode of the superlens is obtained by the spatial phase compensation algorithm of the converging electromagnetic energy Among them, Z feed Z is the distance between the feed antenna and the superlens. focal r is the distance between the desired focal point and the superlens. i Let φ be the distance from any superlens unit to the center point of the superlens, and φ0 be the initial phase of the electromagnetic wave. When the electromagnetic wave reaches the superlens, it can be considered as a plane wave, i.e., φ0 = 0.

[0011] S4. Based on the spatial phase distribution N0(x,y) obtained in step S3, perform quantization with a phase step of 10° to obtain the quantized phase arrangement M0(x,y), and evaluate the error of the quantized electromagnetic energy.

[0012] S5. Discretize the phase arrangement N0(x,y) obtained in step S3 and the quantized phase arrangement M0(x,y) obtained in step S4 to obtain N0(x,y). m ,y n ) and M0(x m ,y n );

[0013] S6. Compare and analyze the discrete phase obtained in step S5 to obtain the final modular discrete phase P0(x). m ,y n );

[0014] S7. The modularized superlens unit is then processed according to the modular discrete phase P0(x) m ,y n Reconstructing superlenses with different focal points into a modular all-metal superlens with adjustable energy focus;

[0015] Furthermore, in step S6, the modular discrete phase P0(x) m ,y n Modular distribution is performed according to the following formula:

[0016]

[0017] The spatial phase compensation algorithm described in this invention includes multiple phase calculation methods, which are then selected based on their optimality. These methods include a ring array arrangement method, a phased array algorithm, and a maximum power algorithm.

[0018] The field error factor of this invention is less than 1 dB;

[0019] The field enhancement factor of this invention is greater than 5 dB;

[0020] After the energy focus shifts according to this invention, the point of maximum field strength remains within the 3dB error range of the original focus energy.

[0021] The embodiments of the present invention have the following advantages:

[0022] The application provides a modular full-metal superlens to realize focus-adjustable near-field focusing. The designed lens is composed of full-metal units with a phase coverage interval of more than 360°, and the arrangement mode of the units is designed by a phase compensation method to change the position of the desired focus.

[0023] The design strategy of synthesizing the module units can arbitrarily assemble the lens unit arrangement sequence under different focus conditions, so that the manufacturing cost is greatly reduced, and the freedom of lens design is improved. The superlens designed by the application can effectively converge electromagnetic wave energy, and the position of the desired focus can be changed at will.

[0024] Therefore, the modular full-metal superlens designed by the application has the characteristics of high temperature resistance, high degree of freedom and focus adjustability, and can provide a low-cost and light-weight solution for various fields working in the near-field region of an antenna, such as near-field target detection, microwave imaging, biological medicine and the like. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The modular full-metal superlens design flowchart for the embodiment 1 of the application is provided.

[0026] Figure 2 The superlens unit structure schematic diagram provided for the embodiment 1 of the application is provided.

[0027] Figure 3 The superlens focusing electric field energy and its energy curves in different axial directions are provided for the embodiment 1 of the application. (a) superlens focusing electric field energy diagram; (b) x-axis direction energy curve diagram; (c) y-axis direction energy curve diagram; (d) z-axis direction energy curve diagram. DETAILED DESCRIPTION

[0028] The following examples are used to illustrate the application, but not to limit the scope of the application.

[0029] Embodiment 1

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme of the embodiments of the application will be described clearly and completely below in combination with the drawings of the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments of the application.

[0031] As shown in the drawings, Figure 1 The modular full-metal superlens design method described in the embodiment can realize a high-temperature-resistant, high-degree-of-freedom and focus-adjustable super surface lens, and the specific implementation steps are as follows:

[0032] 1) Determine the working frequency of the modular full-metal superlens according to the actual application scenario, and preset the desired focus position fz of the energy convergence;

[0033] 2) According to the working frequency determined in step 1), design the full-metal superlens unit and conduct modular modeling, limit the size and thickness of the structure, and realize the regulation range of the incident wave phase over 360°, and the transmission amplitude is more than-3dB;

[0034] 3) According to the expected focus position preset in step 1), the phase distribution of the superlens is obtained by the spatial phase compensation algorithm of converging electromagnetic energy Wherein, Z feed is the distance between the feed antenna and the superlens, Z foca l is the distance between the expected focus and the superlens, r i is the distance from any superlens unit to the center point of the superlens, φ0 is the initial phase of electromagnetic wave, which can be considered as a plane wave when reaching the superlens, that is, φ0=0;

[0035] 4) According to the spatial phase distribution N0(x,y) obtained in step 3), the phase step is quantized to 10°, and the quantized phase distribution M0(x,y) is obtained, and the error of the quantized electromagnetic energy is evaluated;

[0036] 5) Discretize the phase distribution N0(x,y) obtained in step 3) and the quantized phase distribution M0(x,y) obtained in step S4 to obtain N0(x m ,y n ) and M0(x m ,y n );

[0037] 6) Compare the discrete phases obtained in step 5) to obtain the final modular discrete phase P0(x m ,y n );

[0038] The modular discrete phase P0(x m ,y n ) in step 6) is distributed according to the following formula:

[0039]

[0040] The modularized superlens unit is reconstructed into a superlens whole with different focal points according to the modular discrete phase P0(x m ,y n ), forming a modular full-metal superlens with adjustable energy focus.

[0041] The following will be specifically described with reference to the drawings:

[0042] (1) The working frequency is selected as 2GHz, and the focus position f zThe measurements are 0.3m, 0.5m, and 0.75m respectively.

[0043] (2) Based on the operating frequency, 100 different lens units were designed to achieve a control range of over 360° for the incident wave, with each lens unit having a transmission amplitude exceeding -3dB. Each transmission unit is constructed entirely of metallic materials, and 100 different current paths were designed to achieve 100 different phases. The lens unit structure dimensions are 35mm × 35mm × 0.6mm, and the structural model is as follows: Figure 2 As shown.

[0044] (3) For different preset focal positions, the phase distribution N0(x,y) of the metasurface lens with different focal points is obtained according to the phase compensation algorithm.

[0045] (4) Quantize N0(x,y) with a phase step of 10° to obtain the quantized phase arrangement M0(x,y).

[0046] (5) Evaluate the energy error before and after quantization. Specifically, the energy error before and after quantization should be less than 1 dB.

[0047] (6) Discretize N0(x,y) and M0(x,y) and perform comparative analysis on the discrete phases. Specifically, the comparative analysis should meet the rounding principle.

[0048] (7) Selectively obtain the final modular discrete phase P0(x) m ,y n ).

[0049] (8) The modularized superlens unit is based on the modular discrete phase P0(x) m ,y n They are reconstructed into a superlens with different focal points.

[0050] (9) The final superlens was simulated using the finite-difference time-domain method to obtain the focusing electric field energy of the superlens, such as... Figure 3 As shown in (a), it can be observed that the lens generates electromagnetic energy focal points at 0.3m, 0.5m, and 0.75m respectively.

[0051] (10) The energy intensities along the x, y, and z axes are respectively as follows: Figure 3 As shown in (b), (c), and (d), l x l y l z Describe the 3dB attenuation size of the focal spot in the x, y, and z directions, respectively.

[0052] (11) Evaluate the energy enhancement level of this example. Actual parameters are shown in Table 1.

[0053] Table 1:

[0054]

[0055] In summary, this invention presents a modular all-metal lens design method that enables the superlens to operate at high temperatures, reduces the manufacturing cost of the superlens, effectively concentrates electromagnetic wave energy, and allows for arbitrary changes to the desired focal point position.

[0056] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for designing a modular all-metallic meta-lens, characterized in that, The method comprises the following steps: S1, according to the actual application scene, determine the working frequency of the modular full-metal superlens, preset the expected focal point position of energy convergence; S2, according to the working frequency determined in step S1, design the full-metal superlens unit and carry out modular modeling, limit the size and thickness of the structure, and realize the regulation range of the incident wave phase exceeding 360°, and the transmission amplitude exceeds-3dB; S3, the spatial phase distribution of the superlens is obtained by the spatial phase compensation algorithm of converging electromagnetic energy according to the expected focal point position preset in step S1 wherein Z feed is the distance between the feed antenna and the superlens, Z focal is the distance between the expected focal point and the superlens, r i is the distance between any superlens unit and the center point of the superlens, and φ0 is the initial phase of the electromagnetic wave, which can be considered as a plane wave when reaching the superlens, i.e. φ0 = 0. S4, according to the spatial phase distribution N0(x,y) obtained in step S3, the quantization of phase step is 10°, the quantized spatial phase distribution M0(x,y) is obtained, and the error evaluation of the quantized electromagnetic energy is carried out; S5, discretizing the spatial phase distribution N0(x, y) obtained in step S3 and the quantized spatial phase distribution M0(x, y) obtained in step S4 to obtain N0(x, y) and M0(x, y); m n m n ;​​​ S6, comparing the discrete phases obtained in step S5 to obtain the final modular discrete phase P0(x m ,y n ) and distributing them according to the following formula: S7, reconstruct the modularized superlens unit into a superlens whole with different focal points according to the modularized discrete phase P0(x m ,y n ), and form a modularized full-metal superlens with adjustable energy focal points.

2. The method of designing an all-metallic metalens according to claim 1, wherein: The spatial phase compensation algorithm includes a variety of phase calculation methods, and finally the optimal selection is selected, including ring array arrangement method, phased array algorithm and maximum power algorithm.

3. The method of claim 1, wherein: The field error factor is less than 1dB.

4. The method of designing an all-metallic metalens according to claim 1, wherein: The field enhancement factor is greater than 5dB.

5. The method of designing an all-metallic metalens according to claim 1, wherein: After the focal point offset, the maximum field strength point is still within the 3dB error interval of the original focal point energy.

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