TLM: A robust tool for electromagnetics-based optimization

Over the years, Transmission Line Modeling (TLM) has evolved into a robust numerical modeling technique through the pioneering work of P. B. Johns, Wolfgang Hoefer, and others. Using this technique, the electromagnetic (EM) phenomenon is modeled through the propagation of voltages and currents over a network of transmission lines. We review in this paper some of the recent applications of TLM to efficient optimization and modeling of high frequency structures. These applications include TLM-based Space Mapping (SM) optimization and the TLM-based Adjoint Variable Method (AVM). We illustrate these approaches through two examples.