Performance analysis of frequency selective reflectors based on rectangular loop pair for wideband applications

This paper presents performance analysis of single layered bandstop frequency selective surfaces (FSSs) for C -band and ultra-wideband (UWB) frequency ranges respectively. These FSSs are based on polarization dependent (PD) single rectangular loop pair (RLP). RLP arrays in square and rectangular grids are developed and simulated to evaluate signal rejection and reflection for incident transverse electric (TE) and transverse magnetic (TM) waves. Further, orthogonal patterns are printed back-to-back (BTB) on dielectric substrate to study wave propagation and effect on wave polarization. Non-linearities in the reflection phase of BTB arrays are then mitigated by printing orthogonal FSS arrays on the same side of the dielectric substrate. The equivalent circuit models (ECMs) of these FSSs are also presented to predict their transmission characteristics. Later, two FSSs with wideband and ultra-wideband rejection capability are developed and experiments are carried out. The array of merged RLP arranged in square grid exhibits stopband from 4.5 GHz to 8.4 GHz with polarization independence (PI) and it is angularly stable while merged array of RLP arranged in rectangular grid exhibit ultra-wide stopband from 2.3 GHz to 11.5 GHz but it is not angularly stable. The measured transmission responses of all FSSs proposed here are close to simulated results.