Design sensitivity analysis for optimization with the frequency domain-TLM

In this paper, an efficient gradient-based optimization technique with the frequency domain TLM (FDTLM) method is proposed. This is in contrast to the standard approach in which finite differences are used to determine the gradients of the cost function. The proposed technique calculates the gradients using an adjoint-based approach to design sensitivity analysis, in which the gradients are computed with two full wave simulations regardless of the number of design parameters. Thus, computer memory and CPU time are significantly reduced. In addition, re-meshing is not necessary during the optimization process and the TLM structured grid is preserved.