Angular Stable, Dual-Polarized and Multiband Modified Circular Ring Frequency Selective Surface

In this paper, a single-layer multiband slot-type frequency selective surface (FSS), which consists of a modified circular ring loaded with concentric conventional circular ring, is discussed. We have emphasized to design an angular as well as polarization stable multiband FSS structure with reflection characteristics in S-band (2-4 GHz)/K-u (12-18 GHz) and transmission characteristics in X-band (8-12 GHz)/K-a-band (24-28 GHz). A novel synthesis technique is used to obtain the geometrical parameters of the proposed multiband FSS structure, which reduces the number of iterations in the computation process. The proposed multiband FSS structure satisfies the design issues of the frequency response in chosen frequency band of the electromagnetic spectrum and provides significant frequency stability as well as 3-dB bandwidth for both the perpendicular and parallel polarized wave incidence up to 50 degrees. The slot-type modified circular ring FSS structure has been experimentally tested at X-band to validate the synthesis approach.