Triband Frequency Selective Surface With Periodic Cell Perturbation

A novel triband frequency selective surface (FSS) constructed by square loop slots etched on substrate integrated waveguide cavities (SLS-SIWC) is investigated, in which each periodic cell consists of two neighboring SLS-SIWCs with different dimensions. Good selectivity performance of each passband can be easily achieved by tuning the dimensions of the SLS-SIWCs. Besides, the passbands are mainly determined by the corresponding SLS-SIWC in the neighboring perturbed cells and can be designed independently. The performance is verified by measured results, which is insensitive to the variation of incident angles. According to the explicit physical concept, some improved analytical formulas are adopted, which makes the design process straightforward and simple