A Memory-Efficient Implementation of TLM-Based Adjoint Sensitivity Analysis

We present a memory efficient algorithm for the estimation of adjoint sensitivities with the 2D transmission line modeling (TLM) method. The algorithm is based on manipulating the local scattering matrices to reduce the required storage for the original structure simulation associated with lossy dielectric discontinuities. Only one value per cell is stored for two dimensional simulations. Moreover, the connection step for the scattered sensitivity storage is embedded during the adjoint simulation and the sensitivity estimates are calculated on the fly. The required memory storage for our implementation is only 10% of the original implementation of AVM sensitivity with TLM.