Asymptotic convergence in the FDTD and TLM methods

We compare the accuracy of Yee's finite-difference time domain (FDTD) method and the time domain transmission-line matrix (TLM) method in representing internal metal details containing convex and concave edges and corners. We investigate the asymptotic convergence of both methods and propose a simple and effective post-process whereby the asymptotic estimate is obtained with only two coarse-grid simulations. The comparison shows an equivalent or better convergence of the FDTD method in comparison with the TLM method, as well as better accuracy with coarse discretizations.