Analysis and Characterization of Finite-size Curved Frequency Selective Surfaces

Frequency Selective Surfaces (FSSs) are spatial filters that are largely employed in radomes for radars and antennas where high performance is necessary. FSS can be categorised in terms of their frequency behaviour. Band-pass FSS structures are able to let the electromagnetic wave pass in certain frequency ranges and shield others, which are especially suitable for out-of-band stealth of radomes. The properties of frequency selectiveness of these screens are used at microwave and infrared wavelengths. By tuning the electrical size and geometry of the unit-cell (patch or aperture) different frequency behaviours of the structure are generated. Although their analysis and simulation is significantly simplified with the approximation of infinite and planar array, in some real applications FSS are required to be conformal to limited non-planar structures. The literature on the problem of characterizing finite-size and curved FSS has been sparse and more focused on the single application rather than on a unified approach. In the aim of synthesizing valuable techniques, this paper reviews significant research results on truncated and curved FSS which were presented in the dedicated literature.