On the Numerical Errors Induced by the Space-Time Discretization in the LE-FDTD Method

In this work, the accuracy of the lumped element finite-difference time-domain (LE-FDTD) method is discussed in the particular case of a planar distribution of equal resistors. Following the von Neumann technique and assuming a uniform grid, the effective impedance of the lumped resistor has been rigorously derived in a closed form. The result obtained has been compared with the LE-FDTD simulation of a simple test structure. This structure consists of an infinitely long parallel-plate waveguide loaded with the planar distribution of resistors. The excellent agreement obtained validates the approach showing a dependence of the effective resistor impedance on spatial and temporal discretization steps.