Transmission-Band-Switchable Absorptive/ Transmissive Frequency Selective Surface Using Liquid Metal

A transmission-band-switchable absorptive/transmissive frequency selective surface (ATFSS) based on liquid metal is proposed herein. The ATFSS realizes C -band absorption, and the transmissive Ku-band can be turned on or off using loaded or unloaded liquid metal and by changing the spacing between the lossy layer and the transmission layer. The simulation shows that the ATFSS maintains an absorption rate of >80% at 3.1–8.9 GHz; when the transmission band is opened, the | S ₂₁ | < 3 dB band is 10.7–17.22 GHz. When the transmission band is closed, all the electromagnetic waves at the Ku-band are reflected. An ATFSS prototype was fabricated, and the measurement results effectively validated the above design. Moreover, the ATFSS could be used in high-temperature environments owing to the good thermal conductivity of liquid metal.