Analysis of arbitrary frequency-dependent losses associated with conducting structures in a time-domain electric field integral equation

The objective of this letter is to present a solution methodology for the analysis of arbitrary frequency-dependent losses on conducting structures in a time-domain electric field integral equation. The analysis of arbitrary frequency-dependent losses is incorporated in the newly developed marching-on-in-degree (MOD) method to solve the time-domain electric field integral equation. The novelty of this methodology is that both the arbitrary temporal dependence of the frequency-dependent losses and the transient current variations on the conducting structures are expanded in terms of the causal orthonormal associated Laguerre functions. The advantage of implementing these temporal expansion functions is that the convolution between two functional variations, namely the loss factor and the current density, can be treated in an analytical fashion resulting in an accurate and efficient solution methodology. Numerical examples dealing with both time-varying concentrated loads and skin-effect losses on electrically large conducting structures are analyzed to illustrate the potential of this method.