An FSS structure with a band-stop performance for UWB applications

In this paper, a frequency selective surface (FSS) structure with a band-stop performance for ultra-wideband (UWB) applications is introduced. The unit cell of the FSS structure consists of a combination of a square loop, a ring loop, and a cross dipole with four gaps. The unit cell has 0.115 lambda(g) x 0.115 lambda(g) size where lambda(g) is the wavelength in the substrate corresponding to the minimum frequency (2.79 GHz) of the operating band. The bandwidth of the FSS design is from 2.79 to 10.81 GHz frequencies (at normal incidence and |S-21| < -3 dB criterion) which covers all UWB bands. The introduced FSS structure has angular stability up to 80 degrees incident angles both TM and TE polarizations due to the small size of the unit cell. The highest resonance frequency deviation is 0.08% at 80 degrees and this value is quite low. The proposed FSS structure was fabricated and the results obtained through simulations were supported by the measurement results.