A frequency extrapolation algorithm for FISC

A frequency extrapolation algorithm for the fast multipole method (FMM)-based moment method code FISC (Fast Illinois Solver Code) is presented. Our approach is to parameterize the induced current on the target, which is available from the FISC solution based on a multipath excitation model. The ESPRIT super-resolution algorithm is applied to extract the time-of-arrival and amplitude parameters in the model. Once the frequency-dependent model of the induced current on the target is constructed, the induced current can be extrapolated to a broad band of frequencies and the multifrequency scattered field can be computed. The range profiles for a missile model are calculated in this manner to demonstrate the accuracy and performance of the algorithm.