Design And Simulation Of Energy Selective Surface

In recent years,the technology of high power microwave(HPM)weapons and electromagnetic pulse(EMP)weapons were developed at a rapid pace therefore more and more attention has been paid on electromagnetic protection.Energy selective surface works with the mechanism of changeable surface impedance.It achieves the function of simultaneously shielding high-power electromagnetic waves and transmitting low-power electromagnetic waves through the transformation of its surface impedance which,is considered to be an effective device used in RF front-end protection of electronic information systems.This dissertation focuses on the study on the design and simulation of the voltage controlled conductive energy selective surface.By taking advantage of the various shapes of conductive unit and the design of double-layer surface,performance of energy selective surface is improved —— insertion loss decreased,screen effectiveness augmented and its state-changing threshold more sensitive.Then,we made an energy selective surface radome which was intended to protect RF front-end of GPS system.Part of the steady-state transmission characteristics of double-layer energy selective surface and energy selective surface radome were experimentally tested.The main researches of this dissertation are listed as the following three aspects:1.The equivalent circuit method was used to simulate and analyze the energy selective surface transmission characteristics of steady state.The results are compared with those of CST simulation.Meanwhile,parameters of surface energy selection were analyzed after which we studied the electromagnetic transmission characteristics of energy selective surface consisting of cross,circular and hexagonal conductive element.2.The performance of double-layer energy selective surface was studied compared with that of the single-layer structure.Various methods such as electromagnetic simulation,equivalent circuit and field circuit combined simulation were used to analyze the performance of two-layer structure.Meanwhile,influence of the medium parameters on transmission characteristics of energy selective surfaces was analyzed by simulation.Then,we groped for methods of lowering the insertion loss by making use of double-layer structure and the asymmetric two-layer energy selective surface structure was designed and simulated.Subsequently,we made the double-layer energy selective surface sample,using absorbing wall fenestration to experimentally study its performance.3.Aimed at electromagnetic protection of RF front-end of the GPS system,we designed energy selective surface radome and established the antenna and radome system model.The radome's impact on the performance of GPS antenna was simulated and analyzed including the description of the radome's protecting performance.Then,we produced energy selective surface radome and experimentally studied the influence on positioning performance of GPS system which was brought by the radome combined with energy selective surface.