An Ultra-thin, Flexible FSS with Simultaneous Stop-Pass EM Filtering

In this paper, an ultra-thin, single layer FSS is reported that enables simultaneous band-stop and band-pass filtering windows across the wide spectrum of 4-26 GHz. A pass-band of 12.5-13.6 GHz (fractional BW of 8.4%) is achieved which is accompanied by two stop bands on either side that attenuate within frequency ranges of 7.7-10.5 GHz (fractional BW of 30%) and 16.5-20.1 GHz (fractional BW of 19.5%), respectively. Moreover, the shielding effectiveness offered by the two stop bands peak at around 50 dB and are insensitive to the incident polarization. The unit-cell of the proposed FSS constitutes a square metallic patch with an etched circular slot and a thin hoop-type resonator, all of which, is printed on a thin flexible polyimide substrate thereby making it an ideal candidate for EM spatial filtering applications in miniaturized communication systems.