Modeling and analysis of doubly-curved frequency selective surface

As a spatial filter, frequency selective surface (FSS) has been intensively investigated for many years. The applications of FSS are always needed to be conformal. So modeling and analysis conformal FSS (CFSS) is particularly important. In this paper, three projection methods for modeling the doubly-curved frequency selective surfaces (DCFSS) are investigated. We compare the different effects of these methods on the performance of FSS. Then, a hyperboloid, as a sub-reflector in 93GHz Cassegrain system, is designed as an example. We find that the projection methods all could be successfully applied in the design if the curved surface within electrically large size and small curvature.