Broadband Monostatic RCS and ISAR Computation of Large and Deep Open Cavities

A hybrid algorithm that combines the finite-element time-domain (FETD) method and generalized scattering matrix (GSM) technique is proposed to efficiently compute the broadband monostatic radar cross section (RCS) of a large and deep open cavity. The formulation and implementation for the numerical modal analysis of arbitrary cross sections and the FETD method equipped with complex frequency-shifted perfectly matched layers for transient simulations are presented. The broadband monostatic RCS is evaluated using a broadband GSM obtained by the FETD solutions. Several examples are presented to demonstrate the accuracy and efficiency of the proposed hybrid FETD-GSM algorithm for broadband monostatic RCS computation and inverse synthetic aperture radar imagery of large and deep open cavities.