Wide-Passband Reconfigurable Frequency Selective Rasorber design based on Fluidity of EGaIn

In this paper, a wide-passband reconfigurable frequency selective rasorber(FSR) design based on fluidity of liquid metal is proposed. The proposed FSR is implemented via combining two lossy layers with a reconfigurable frequency selective surface(FSS). Firstly, a third-order broadband FSS with reconfigurable properties is presented, whose bandpass state can be switched to perfect reflection state by controlling the injection and the extraction of liquid metal in microchannels. Secondly, the upper lossy layer is a symmetrical split-ring resonator(SSRR) structure composed of a screen-printed resistive film, and the lower lossy layer is a square loop, each side of which is inserted with a circular spiral resonator(CSR) in the center, thereby introducing a wide transmission window in the broad absorption band. Then, by cascading the lossy layers and the lossless layer through an air layer with a thickness of about a quarter wavelength, the design can realize the reconstruction of absorption-transmission-absorption(ATA) mode and absorption-reflection-absorption(ARA) mode. It is shown by full-wave simulation that the structure has a wide-passband filtering performance with a fractional 3dB bandwidth reach up to 41.6%, the minimum insertion loss in the passband is 0.98dB at 12.4GHz, and the relative bandwidth of 110.6% with reflectivity less than −10dB in ATA mode. In ARA mode, it has a good absorption band from 4.8GHz to 10.4GHz and15.1GHz to 19.6GHz and the 3dB transmission bandwidth is 12.8%. The proposal has significance to be used to design switchable stealth radome for wide-band antennas.