Efficient sensitivity analysis of lossy discontinuities using time-domain TLM

For the first time, the adjoint variable method (AVM) is applied to the efficient sensitivity analysis of lossy discontinuities with the time-domain transmission line modeling (TLM) method. Using only two simulations, of the original and adjoint systems, the sensitivities of the objective function with respect to all design parameters are estimated. The adjoint system is running backward in time, with its excitation extracted from the original simulation. The algorithm is illustrated through the wideband S-parameter sensitivity analysis of a dielectric resonator waveguide filter.