Note on the S-11-parameter and input impedance extraction in antenna simulations using FDTD

In a resistive voltage source (RYS) formalism, the feed impedance is known to be distorted due to the cell capacitance. In this letter, examples are g iven showing that the effect of the distortion may be significant. We propo se a simple way to derive the S-11-parameter without the uncertainly associ ated with the feed port impedance distortion. Furthermore, the input impeda nce is shown to be independent of the cell height anti source model chosen. (C) 2001 John Wiley & Sons, Inc.