Ultrathin and Miniaturized Frequency Selective Surface With Closely Located Dual Resonance

Ultrathin and miniaturized frequency selective surface (FSS) with closely located dual bands is proposed in this letter. The proposed FSS comprises parallel patches and meandering lines that construct parallel LC resonators. Then, two independent passbands can be achieved and adjusted by only changing corresponding structure parameters of the element. Through a cater-corner arrangement, the structure avoids the effect introduced by the unnecessary inductance. The proposed FSS resonates at 1.59 and 1.96 GHz with a low resonant frequency ratio of 1.23. The proposed FSS provides a low profile of 0.13 mm and a miniaturized unit cell size as compact as 0.042λ × 0.042λ. A simplified equivalent circuit model is established, which provides good insight into the operation mechanism. Finally, a prototype of the proposed structure is fabricated and measured. All the results present excellent resonant stability with respect to different polarizations and incident angles up to 60°.