Design of Flexible Bandpass Frequency Selective Surface with High Out-of-band Suppresion

A flexible frequency selective surface (FSS) with high upper suppression is presented. The proposed FSS is composed of two flower-shaped metallic patterns on the top/bottom and a coupling aperture in the middle layer with petal-shaped slots. They are all etched on thin polyimide substrates and supported by flexible thin teflon substrates. The coupling aperture structure introduces two transmission zeros which greatly improve the frequency selectivity. The simulated results show that the flexible FSS performs at 17.2GHz with an insertion loss of 0.3dB and a 3-dB fractional bandwidth of 30.2%, ranging from 14.6GHz to 19.8GHz, which also exhibits incident-angle insensitive and polarization independent property.