Transient analysis of the EM field coupling to multi-conductor transmission lines using the NILT method

A simple and efficient numerical inversion Laplace transform (NILT) algorithm is implemented in MATLAB environment based on the quotient difference method to solve the problem of electromagnetic (EM) field coupling to lossy or lossless multi-conductor transmission lines (MTL) illuminated by an EM incident field. Two major points are treated in this work for the lossy MTL system excited by an incident EM field; the first one is the optimum equivalent circuit taking into consideration the different physical concepts based on the transmission line theory and the second point deals with the choice and implementation of the numerical method for less computing time and for efficient results. In this paper, the effect of the EM coupling is treated and it is based on the superposition effect of each distributed voltage current sources using the NILT numerical method. Results of the near end and far end voltages and currents for an MTL system are presented and displayed for two types of microwave (MW) structures in the time domain for the case of a plane wave excitation. It has been shown that a non-homogeneous MW structure or multilayered system with a specific choice of the dielectric constant has an advantage for less transient EM coupling due to the external EM field.