Multiband Metallic Frequency Selective Surface With Wide Range of Band Ratio

A novel metallic multiband frequency selective surface (FSS) is presented. The proposed FSS structure has operation bands from closely spaced to far fromeach other (wide range of band ratio) and has high selectivity at each operation band. The unit cell comprises four small square slots, each loaded with multiple stub resonators. The stubs are placed in each slot in such a way that the unit cell response to both TE and TM polarizations are the same. To miniaturize the unit cell and cover the lower frequency range, each stub resonator is terminated with a U-shaped section. The length of each stubs within the slot determine the resonant frequency of each passbands. The band ratio can be set from 1.09 (close to each other) up to 2.35 (far from each other). Single, dual, triple, and quad band FSS structures are designed and simulated through HFSS software package. The fabricated dual-band unit cell shows that the proposed FSS structure can provide two close to each other bands, 9.8 and 10.9 GHz. Also, the measured results of a fabricated dual-band 17 x 17 FSS array show a relatively stable response to variations of incidence angle and polarization state.