An analytical and numerical analysis of several locally conformal FDTD schemes

The virtues of the finite-difference time-domain (FDTD) method for the elec tromagnetic analysis of arbitrary complex metal and dielectric structures a re well known, Almost equally well known are the difficulties encountered b y the technique when the material boundaries do not coincide with the Carte sian mesh. Until recently, there were few alternatives to the simple, but i naccurate, staircase approximation for these cases, However, over the past few years, there have been several solutions proposed, which maintain the s implicity and efficiency of the FDTD method while providing an accurate tre atment of curved, offset, or sloping metallic boundaries, In this paper, an alytical and numerical comparisons are presented and a clear recommended me thod is shown to emerge.