A terahertz broadband optoelectronic fusion metasurface transceiver antenna

Abstract

This invention discloses a terahertz broadband optoelectronic fusion metasurface transceiver antenna, belonging to the field of antennas. In order to solve the problems of narrow working bandwidth and low efficiency of traditional electrically tuned metasurface antennas, the present invention adopts a mechanically movable feed source to achieve beam scanning of the metasurface antenna. The main beam gain direction of the metasurface antenna is determined by the moving feed source. This method can effectively reduce the gain roll-off within the beam scan and improve the broadband working capability of the transceiver antenna. At the same time, due to the absence of power consumption of other electrically tuned devices, the working efficiency of the embodiments of the present invention can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of terahertz antennas, and in particular relates to a broadband optoelectronic fusion metasurface transceiver antenna suitable for terahertz communication systems. Background Art

[0002] As wireless communications demand for bandwidth increases, carrier frequencies are gradually expanding into the terahertz band. While the terahertz band, a crucial application band for future communications, boasts abundant spectrum resources, it still suffers from significant electromagnetic wave transmission losses. Based on these advantages and disadvantages, the present invention proposes the use of metasurface antenna technology. Metasurface-based beam-steering antennas can achieve higher directional gain and highly directional radiation in the terahertz band.

[0003] Furthermore, in the terahertz band, metasurface transceiver antennas based on electrically tuned systems have a narrow overall operating bandwidth due to the limited bandwidth of the electrically tuned devices themselves, which does not meet the wide bandwidth requirements of the terahertz band. Furthermore, traditional electrically tuned systems suffer from excessive energy consumption and low operating efficiency. To address these issues, there is an urgent need to provide a broadband and efficient design approach to enable the application of broadband transceiver antennas in the terahertz band. The feed source mobile design based on a mechanical scanning mechanism proposed in this invention can meet the design requirements of broadband transceiver antennas in the terahertz band.

[0004] At the same time, the present invention uses a signal generation mechanism that differs from traditional electronic signal generation methods. Adopting photonic theory, the signal is generated in a beat frequency manner, enabling the generation of instantaneous broadband signals. By amplifying and mixing the broadband optical signal, a stable broadband electrical signal is obtained and loaded onto the terahertz broadband metasurface transceiver antenna. The terahertz broadband optoelectronic fusion metasurface transceiver antenna described in this invention is an important technical approach with broad application value in new-generation terahertz satellite communications, mobile communications, radar detection, and imaging. Summary of the Invention

[0005] In order to solve the problems of narrow working bandwidth and low efficiency in traditional electrically tuned metasurface antennas, the present invention adopts a mechanically movable feed source to achieve beam scanning of the metasurface antenna. The main beam gain direction of the metasurface antenna is determined by the movable feed source. This method can effectively reduce the gain roll-off within the beam scanning and improve the broadband working capability of the transceiver antenna. At the same time, since there is no power consumption of other electrically tuned devices, the working efficiency of the embodiment of the present invention can be improved. The purpose of the present invention is to provide a terahertz broadband optoelectronic fusion metasurface transceiver antenna, which aims to solve the problem of limited working bandwidth of the transceiver antenna in the current terahertz communication system in response to the defects of the background technology.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a terahertz broadband optoelectronic fusion metasurface transceiver antenna, which includes two lasers, an optical phase-locked loop, a coupler, an optical amplifier, an optical mixer, and a metasurface array antenna; two lasers, an optical phase-locked loop, a coupler, an optical amplifier, and an optical mixer, two lasers generate two optical signals with different frequencies, the optical signals output by the two lasers are injected into the optical phase-locked loop, and then pass through the coupler, the optical amplifier, and the optical mixer in sequence, and the optical mixer outputs an electrical signal to the metasurface array antenna, providing broadband signal excitation for the metasurface array antenna;

[0007] The metasurface array antenna is composed of a plurality of metasurface units arranged in an array, and each metasurface unit is composed of, from top to bottom: an upper patch, a Rogers 4350B dielectric plate 1, a metal intermediate layer, a Rogers 4450F dielectric plate, a Rogers 4350B dielectric plate 2, and a bottom patch;

[0008] The upper patch and the bottom patch are made of metal, the bottom patch is an equilateral triangle structure, and the upper patch is an equilateral triangle structure with an opening. The side length of the equilateral triangle structure of the bottom patch and the upper patch is 0.71mm; an opening is set on one side of the base of the upper equilateral triangle, and the side length of one side after the base opening is 0.13mm, the side length of the other side is 0.41mm, and the opening depth is 0.17mm; a metal through hole is set in the bottom corner of the other side of the base of the equilateral triangle opposite to the opening, and the metal through hole is used to connect the upper patch and the bottom patch, and the diameter of the metal through hole is 0.2mm;

[0009] The Rogers 4350B dielectric plate 1, metal intermediate layer, Rogers 4450F dielectric plate, and Rogers 4350B dielectric plate 2 are all square structures with a side length p of 1.04 mm. The corresponding thicknesses are 0.762 mm, 0.018 mm, 0.1 mm, and 0.762 mm, respectively. The relative dielectric constant of the Rogers 4350B dielectric plate is 3.66, corresponding to a loss tangent of 0.0037; the relative dielectric constant of the Rogers 4450F dielectric plate is 3.7, corresponding to a loss tangent of 0.004.

[0010] The bottom corner opposite to the metal through hole of the bottom patch is parallel to one side of the Rogers4350B dielectric board; the position of the upper patch is: rotated based on the corresponding position of the bottom patch with the metal through hole as the rotation center, but the upper patch does not touch the boundary of the metasurface unit.

[0011] Furthermore, the metasurface array antenna additionally includes a horn feed, which is a circularly polarized horn feed or a linearly polarized horn feed.

[0012] The beneficial effects of the present invention are:

[0013] 1. To address the narrow bandwidth and low efficiency of terahertz-band metasurface antennas, this paper proposes a terahertz broadband optoelectronic fusion metasurface transceiver antenna. This antenna utilizes the instantaneous broadband signal provided by a laser to generate broadband electrical signals, providing stable broadband electrical signal output for subsequent metasurface antennas.

[0014] 2. The present invention realizes the angular scanning of the main beam by spatial movement of the feed position, and the position can be adjusted at any time according to actual needs. It has high flexibility and ensures broadband working performance.

[0015] 3. The broadband multipolarization transmission unit provided by this invention incorporates a metasurface design with a multi-layer stacked structure, enabling the series connection of capacitors and inductors between the layers. This increases the unit's operating bandwidth and better utilizes the abundant spectrum resources in the terahertz band. The overall design is simple, compact, and reduces manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram of the principle of a terahertz broadband optoelectronic fusion metasurface transceiver antenna provided by an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the principle of metasurface conical scanning based on feed position adjustment provided by an embodiment of the present invention;

[0018] Figure 3 The 3-bit coding metasurface unit structure and amplitude-phase characteristic curve provided by the embodiment of the present invention;

[0019] Figure 4 These are the simulation and test results of the 40×40 element metasurface antenna provided by an embodiment of the present invention;

[0020] Figure 5 This is a graph showing the E-plane beam scanning test results of the 40×40 element metasurface antenna provided by an embodiment of the present invention at frequencies of 100 GHz, 120 GHz, and 140 GHz. DETAILED DESCRIPTION

[0021] Figure 1 This is a block diagram of a terahertz broadband optoelectronic metasurface transceiver antenna. It primarily consists of two lasers, an optical phase-locked loop (PLL), a coupler, an optical amplifier, an optical mixer, and a metasurface array antenna. The two lasers generate two optical signals with different frequencies. These signals are then injected into the PLL and coupled within the optical fiber to achieve a constant signal frequency difference. The optical signal is then output, followed by an optical amplifier and an optical mixer, ultimately converting the instantaneous broadband optical signal into a broadband electrical signal, providing stable broadband signal excitation for the subsequent terahertz broadband metasurface transceiver antenna. Figure 1This is a block diagram of the principle of the terahertz broadband optoelectronic fusion metasurface transceiver antenna provided by the present invention. This embodiment uses a photonic beat frequency method to generate a terahertz carrier wave, employing two independent laser sources and optical phase-locking technology to coherently process the two independent laser beams. After optical power amplification, each optical signal enters an optoelectronic mixer to achieve optoelectronic signal conversion. The signal is then directed into free space through the metasurface antenna array.

[0022] like Figure 2 As shown, a schematic diagram of the principle of the metasurface conical scanning based on feed position adjustment of the present invention is provided. The spatial compensation phase calculation of the unit of the traditional transmission array antenna can be obtained by the following formula:

[0023]

[0024] k0 is the spatial propagation constant, R i Feeding to mn th The distance between units, mn th The position vector of the cell, is the required main beam pointing, ψ0 is the set phase constant, and is the relative transmission phase.

[0025] To obtain a larger main beam deflection angle It can be obtained from the following formula:

[0026]

[0027] Subtracting the above two equations yields:

[0028]

[0029] That is, after the initial feed position, initial main beam pointing, and corrected main beam pointing are given, the feed position R i ' can be confirmed.

[0030] like Figure 3 As shown, the 3-bit coded metasurface unit structure and amplitude-phase characteristic curve provided by an embodiment of the present invention, the metasurface array periodically arranges 40×40 element metasurface units, the array design is based on the maximum normal gain constraint, a cone horn with a gain of 20dBi is used for excitation, and the ratio F / D of the distance from the phase center of the feed source to the geometric center of the array to the maximum aperture of the array is 1. By rotating the upper patch of the metasurface unit to different angles, the corresponding 3-bit unit can be obtained. The transmission amplitude of the 3-bit coded metasurface unit is greater than -3dB, and the transmission phase of the 3-bit coded metasurface unit covers 360° in the range of 100GHz-140GHz. The transmission array antenna designed based on the metasurface unit shown in the present invention can be processed using traditional PCB technology.

[0031] The overall test structure provided in this embodiment is as follows Figure 4 As shown, it includes a transmission array and a horn feed located above the transmission array. The transmission array is obtained by arranging m*n transmission unit arrays. In this embodiment, m=n=40. The horn feed adopts a rectangular horn, which is set above the transmission array and can be moved. The center of the transmission array is taken as the origin. The initial position of the horn feed coordinate is (0, 0, 30.9mm), and the aperture size is 21.86mm*21.86mm. The 40×40 element metasurface antenna has been simulated and tested, as shown in the figure. Figure 4 As shown in the figure, a comparison of Matlab simulation results, full-wave software simulation results, and fabrication test results for a 40×40-element metasurface antenna array reveals a consistent gain trend. The antenna array gain reaches 33dBi, and the 3-dB bandwidth covers 110GHz to 140GHz. Based on this, an 80×80-element array can achieve a gain greater than 35dBi.

[0032] Figure 5 This is a graph of the E-plane beam scanning test results of the 40×40 element metasurface antenna provided by an embodiment of the present invention at frequencies of 100 GHz, 120 GHz, and 140 GHz. By adjusting the feed position and changing the direction of the incident wave, a relatively obvious beam scanning effect can be obtained. At 100 GHz, the corresponding beam scanning range is 0°-60°, at 120 GHz, the corresponding beam scanning range is 0°-50°, and at 140 GHz, the corresponding beam scanning range is 0°-40°.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A terahertz broadband optoelectronic fusion metasurface transceiver antenna, comprising two lasers, an optical phase-locked loop (PLL), a coupler, an optical amplifier, an optical mixer, and a metasurface array antenna. The two lasers, the optical phase-locked loop (PLL), the coupler, the optical amplifier, and the optical mixer generate two optical signals with different frequencies. The optical signals output by the two lasers are injected into the PLL, then sequentially pass through the coupler, the optical amplifier, and the optical mixer. The optical mixer then outputs an electrical signal to the metasurface array antenna, providing broadband signal excitation for the metasurface array antenna. The metasurface array antenna is composed of a plurality of metasurface units arranged in an array, and each metasurface unit is composed of, from top to bottom: an upper patch, a Rogers 4350B dielectric plate 1, a metal intermediate layer, a Rogers 4450F dielectric plate, a Rogers 4350B dielectric plate 2, and a bottom patch; The upper patch and the bottom patch are made of metal, the bottom patch is an equilateral triangle structure, and the upper patch is an equilateral triangle structure with an opening. The side length of the equilateral triangle structure of the bottom patch and the upper patch is 0.71mm; an opening is set on one side of the base of the upper equilateral triangle, and the side length of one side after the base opening is 0.13mm, the side length of the other side is 0.41mm, and the opening depth is 0.17mm; a metal through hole is set in the bottom corner of the other side of the base of the equilateral triangle opposite to the opening, and the metal through hole is used to connect the upper patch and the bottom patch, and the diameter of the metal through hole is 0.2mm; The Rogers 4350B dielectric plate 1, the metal intermediate layer, the Rogers 4450F dielectric plate, and the Rogers 4350B dielectric plate 2 are all square structures with a side length p of 1.04 mm. The corresponding thicknesses are: 0.762mm, 0.018mm, 0.1mm, 0.762mm; The relative dielectric constant of the Rogers4350B dielectric plate is 3.66, corresponding to a loss tangent of 0.0037; the relative dielectric constant of the Rogers4450F dielectric plate is 3.7, corresponding to a loss tangent of 0.004; The bottom corner opposite to the metal through hole of the bottom patch is parallel to one side of the Rogers4350B dielectric board; the position of the upper patch is: rotated based on the corresponding position of the bottom patch with the metal through hole as the rotation center, but the upper patch does not touch the boundary of the metasurface unit.

2. The terahertz broadband optoelectronic fusion metasurface transceiver antenna according to claim 1, characterized in that: The metasurface array antenna also additionally includes a horn feed, which is a circularly polarized horn feed or a linearly polarized horn feed.

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