Reduced-order modeling of multiscreen frequency-selective surfaces using Krylov-based rational interpolation

A method is presented for generating a broad-band rational interpolant appr oximation of the reflection coefficient of multiple-screen frequency-select ive surfaces (FSSs), The technique is structured around a linearization of the system provided by a spectral domain moment method-based analysis of th e FSS, followed by a model-order reduction of the linearized system using t he dual rational Arnoldi method. This process creates a rational interpolan t of the linearized system that matches its transfer function and its deriv atives at several expansion points in the Laplace domain. Numerical results indicate that a reduced-order model with a system matrix of dimension less than 20 x 20 can accurately reproduce the broad-band behavior of multiscre en FSSs originally modeled with several hundreds or thousands of unknowns.