Investigation On Electromagnetic Cancellation Metasurface

With the continuous improved requirements of radar system for detection target recognition and the rapid development of information technology,the level of radar detection technology has been greatly improved.In order to improve the survivability of the battlefield and reduce the Radar Cross Section(RCS)of aircraft and warships,the radar stealth technology to reduce the probability of detection highlights shows its extremely important value in today’s combat environment at home and abroad for academic and defense engineering,and the field has caused widespread concern and research.There is a kind of metasurfaces applying for the radar stealth technology,and the metasurface exhibits excellent characteristics for radar echo reduction.The electromagnetic cancellation technology uses the space electromagnetic wave coherent cancellation principle to realize the inverse superposition of the space incident wave and the reflection wave,thereby achieving the reduction of backward RCS.This paper focuses on the research of electromagnetic cancellation metasurface with RCS reduction characteristics,the research work can be summarized as the following parts:Firstly,based on the resonance characteristics of periodic elements and the coherent superposition of mirror principle,the rotationally symmetric electromagnetic cancellation metasurface,microstrip reverse-biased electromagnetic cancellation metasurface and microstrip wave-path difference inversed electromagnetic cancellation metasurface are studied.The analytical model was established by the equivalent circuit method,and the reflection characteristics were explored by the electromagnetic simulation of HFSS software.The simulation and experimental results show that the reflection energy intensity of the metasurface in the frequency range of 4.1GHz-5.6GHz is about 10 dB lower than that of the metal plate in the case of vertical or horizontal polarized waves in vertical incidence,RCS has also decreased by 10 dB.Secondly,by introducing active impedance loading technology into the rotationally symmetric electromagnetic cancellation metasurface,a tunable electromagnetic cancellation metasurface is proposed,and the tunable electromagnetic cancellation metasurface of C-band and Ku-band is simulated.The results show that the two metasurfaces respectively realize the working band switching between 3.78GHz-4.60 GHz and 4.39GHz-5.72GHz(bandwidth extends from 29.5% to 40.8%);12.23GHz-14.57 GHz and 14.57GHz-17.37GHz(bandwidth expands from 17.5% to 34.7%).Finally,the application of electromagnetic cancellation to metasurface is proposed.A linearly polarized antenna-electromagnetic cancellation metasurface integrated device and a circularly polarized antenna-electromagnetic cancellation metasurface integrated device are studied.The integrated structure can be switched between stealth function and antenna radiation function in the working frequency band.Simulation experiments on two integrated structures show that in the stealth function,the two integrated structures respectively achieve low RCS performance in the frequency band of 4.1GHz-4.4GHz and 4.7GHz-5.8GHz;4.2GHz-4.4GHz and 4.7GHz-5.8GHz compared to the metal plate echo intensity.In the antenna function,the linearly polarized antenna-electromagnetic cancellation metasurface integrated structure achieves the return loss of 10 dB or more and a gain of 7.5dB or more in the 4.1GHz-5.7GHz band(maximum gain realizes 9.25 dB near 5.5GHz);the circularly polarized antenna-electromagnetic cancellation metasurface integrated structure achieves the return loss more than 10 dB in the 4.0GHz – 5.5GHz band,axial ratio below 3dB in the 4.45GHz-4.75 GHz band and gain above 8dB(maximum gain realizes 9.6dB near 5.2GHz).