A time-domain optimization technique for the simultaneous reconstruction of the characteristic impedance, resistance and conductance of a transmission line

Simultaneous reconstruction of the characteristic impedance, series resistance and shunt conductance of a nonuniform transmission line, using the transient response, is considered. The method that is used is based on the time-domain wave-splitting technique and the compact Green functions technique. The reconstruction algorithm is iterative and based on a conjugate gradient method. Exact expressions for the gradients are given in terms of dual functions. The question of the uniqueness and ill-posedness of the inverse problem is addressed. Numerical results of reconstructions are given.