Planar X-Band Reflecting Surfaces Based on Rhombic Loop Pair

This paper presents design and analysis of two band stop FSSs offering wider band rejection along with polarization independence and linear reflection phase characteristics separately. The polarization dependent vertical dual rhombic loop (VDRL) unit cells arranged with periodicity ratio 1:2 as well as horizontal dual rhombic loop (HDRL) with periodicity ratio 2:1 exhibit two separate stop bands for TE and TM incident EM waves. Both FSSs are evolved from orthogonally oriented polarization dependent arrays of rhombic loop pairs those are first printed on both sides of dielectric substrate back-to-back (BTB) to form a BTBDRL FSS and later merged together on same side of dielectric substrate to form merged dual rhombic loop (MDRL) FSS respectively. The transmission responses of both VDRL and HDRL FSSs for orthogonally polarized incident EM waves coincide when they are cascaded back-to-back on both sides of dielectric material. The non-linearities in their reflection phase responses are compensated by merging both the arrays on the same side of dielectric substrate. The array of BTBDRL exhibits 4.15 GHz wide stop band with two transmission nulls at 7.46 GHz and 9.52 GHz respectively while the MDRL FSS provides 4.8 GHz wide stop band centered at 8.2 GHz.