Terahertz FSS for space borne passive remote sensing application

A terahertz frequency selective surface (FSS) which operates inside the spatial filtering front-end of a high sensitivity receiver is proposed and experimentally verified. To achieve this terahertz FSS metamaterial which exhibits extremely low insertion loss and is insensitive to the variations of polarisations and incident angles, the FSS array is constructed by an electrically thick SiO₂ layer (quartz wafer) and an ultra-thin high conductivity aluminium layer with periodic aperture unit cells. The micro-machined metallic pattern is shaped by the combination of a sub-wavelength circular ring and a split-ring resonator. Experimental results and predicted spectral responses are shown to be in good agreement over the frequency range of 0.1-0.5 THz.