A time domain method for determining the relaxation time spectra

Many electromagnetic field problems can be expressed as a Fredholm integral equation of the first kind or the second kind. The step response of many linear physical systems may be analysed as sums of decaying exponentials. The paper describes a procedure (which improves the performance of gradient techniques) for the calculation of the amplitudes and the relaxation times which fit the sum of exponential functions to the experimental data. This method is applied to simulated and experimental data in order to validate the algorithm.