3-D Frequency Selective Surfaces Based on Guided-Wave Structures: Proposal, Theory, and Application

Frequency-selective surface (FSS) is a periodic artificial structure that can produce electromagnetic selectivity. Various types of structures, analysis theories, and design methods have been developed for conventional FSSs. Unfortunately, these FSSs manipulate electromagnetic waves through their 2-D or 2.5-D periodic elements, thus leading to serious limitations to their filtering performance and design flexibilities. Recently, a new class of 3-D FSS, consisting of 3-D guided-wave cavities or structures, has attracted much attention. Owing to this special construction of periodic elements, 3-D FSSs can provide more degrees of freedom in the spatial dimensions to exhibit superior performance features. This paper aims to introduce a kind of 3-D FSS based on slot-line structures with a focus on the state-of-the-art techniques in the design and exploration of bandpass FSSs.