Two-stage complex image method for a thin-thick dielectric layer combination in microstrip substrates

A two-stage complex image technique is presented, in which the spectral function is processed twice using Prony's method. In this two-stage process, two different truncation points are used to ensure that both the dielectric film and the microstrip substrate are included accurately. An overlaid microstrip line is calculated to verify the accuracy of the two-stage complex image method. Although only one case is examined, that is, the dipole and the observation points located at the film-substrate interface, the two-stage complex image method also applies to other cases where the dipole and/or the observation points are located above the thin film and within the thick substrate.<>