A Novel Metamaterial Rasorber for Broadband Transmission in S Band

A novel rasorber based on frequency selective surface with lower-frequency transmission and higher-frequency absorption is designed. It consists of three layers, the top layer is loss layer made up with square resistance sheets, and the middle and bottom layers are lossless bandpass layers made up with square ring metal slits. The simulation results show that under the normal incidence, an insertion loss less than 1 dB from 2. 6 GHz to 3. 6 GHz and a reflectivity less than -10 dB from 8 GHz to 12 GHz are realized. Furthermore, the broadband absorption and transmission mechanisms of the structure are analyzed by full-wave electromagnetic simulation and equivalent circuit method. An experimental-demonstration sample plate is fabricated by printed circuit board process, and the measurement results are in good agreement with the simulation results. It is proved that the proposed rasorber has great application value in the field of stealth radome.