Accurate computation of wideband response of electromagnetic systems utilizing narrowband information

The concept of analytical continuation is utilized to generate the electromagnetic response over a wide frequency band. The problem of interest is TM scattering from a conducting cylinder. A method of moment formulation is utilized to generate information about the current and its derivatives at a set of specific frequencies. This information is utilized to extrapolate the current at other frequencies. The numerical results presented are in good agreement with exact data. Two techniques, namely frequency derivative and Cauchy's technique have been introduced for extrapolating and interpolating a rational function, respectively, from a few samples of frequency responses and their derivatives. This technique can be used to speed up the numerical computations of parameters like input impedance and RCS of any linear time-invariant system.