Harmonic-Suppressed Frequency Selective Rasorber Using Resistive-Film Sheet and Square-Loops Resonator

A harmonic-suppressed (HS) frequency selective rasorber (FSR) based on square-loops resonators and resistive-film sheets is presented in this letter. The FSR is designed by cascading the bandpass frequency selective surface (FSS) and broadband absorber together, which owns a main passband at center frequency of 8 GHz, with harmonic transmission windows suppressed and out-of-band reflection absorbed from 12 to 26 GHz. A lossless FSS with a bandpass response and a lossy absorber with broadband absorption are analyzed by equivalent circuit model, respectively. The frequency range of harmonic suppression covers three octaves of main passband frequency. Besides, the measured results agree well with the simulated ones. The proposed HS-FSR could be used as radome in enhancing an anti-interference performance of a wireless communication system and improving the stealth performance of a radar platform.