Design And Optimization Of Metasurface Based On Multi-Objective Parallel Particle Swarm Optimization

In the past ten years,people have conducted extensive and in-depth research on metasurfaces.By adjusting the equivalent impedance of the structure,the propagation of electromagnetic waves can be flexibly controlled,thereby realizing various functions,including electromagnetic stealth,holographic imaging,metasurface lens,etc.At first,once the traditional passive metasurface is fabricated,the function is solidified with no tunability,which limits its capability and greatly restricts its application in practical scenarios.With the development of metasurface technology,various reconfigurable devices have been introduced into the design of metasurface to enable real-time control of electromagnetic waves.However,it also makes the design of metasurface more complicated.Therefore,how to design metasurface more efficiently and how to design better metasurface have become the focus of attention.This thesis will conduct in-depth research on these two issues,and the specific content is as follows:(1)A multi-objective parallel particle swarm optimization algorithm for MATLAB-CST joint optimization is proposed.Generally,researchers often suffer from the non-unique performance index and time-consuming optimization during the design of metasurfaces.While this algorithm improves the multi-objective optimization problem by seeking the Pareto optimal solution.In addition,we also adopt a master-slave architecture that uses multiple computers to share the full-wave simulation task to improve the optimization efficiency.Finally,an amplitude reconfigurable absorbing metasurface is designed,which realizes rapid optimization of the bandwidth and absorption rate simultaneously,thereby verifying the effectiveness of the algorithm.(2)Using the proposed multi-objective parallel particle swarm optimization algorithm,a dualpolarized reflective 3-bit phase modulation metasurface is designed,which is insensitive to the incident angle of electromagnetic waves.Simulation results verify that the metasurface can achieve a good scattering beam scanning function in the range of 0°～40°.Finally,sample fabrication and experimental tests are carried out to verify the electromagnetic properties of the metasurface.(3)Using the proposed multi-objective parallel particle swarm optimization algorithm,a transmissive single-polarization dual-frequency 1-bit phase modulation metasurface is designed.Two pairs of PIN diodes are loaded into the unit-cell.The ON/OFF state of one pair of PIN diodes is used to control the direction of the surface current on the unit-cell to realize the function of 1-bit transmission phase modulation.Meanwhile,the ON/OFF state of the other pair of PIN diodes is responsible of adjusting the equivalent radiation area of the patch on the unit-cell to achieve dualfrequency switchable function.Finally,a metasurface sample is tested to verify the above functions.