Note on theS11-parameter and input impedance extraction in antenna simulations using FDTD

Abstract

In a resistive voltage source (RVS) formalism, the feed impedance is known to be distorted due to the cell capacitance. In this letter, examples are given showing that the effect of the distortion may be significant. We propose a simple way to derive the S11‐parameter without the uncertainty associated with the feed port impedance distortion. Furthermore, the input impedance is shown to be independent of the cell height and source model chosen. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 28: 8–11, 2001.

A stabilized resistive voltage source for FDTD thin-wire models

“…The time step was set to 0.999 times the Courant limit (of the standard FDTD algorithm). The input impedance was computed using the source-independent method [18], i.e., directly from the definition as a ratio of total voltage and total current at the source cell. Parameter was then computed from the impedance.…”

“…The eigenvalues of the amplification matrix in (17) are given by (18) The maximum stable wire radius can be determined by setting the time step to the Courant limit (of the standard FDTD algorithm) and solving for values of that satisfy . Alternatively, one may set wire radius to a fixed value and solve for the largest stable time step such that .…”

Measured Antenna Response of a Proposed Microwave Tomography System Using an Efficient 3-D FDTD Model

“…Our model implements the formulation described in [19] and [20] to update the field components in both transmitting and receiving ends. The resulting update equation for component, using the RVS, takes the form…”

A circularly polarized dielectric resonator antenna excited by an asymmetrical U-slot with a backing cavity

“…Another technique used in this letter is the source independence resistive voltage source (RVS) [10]. So far, the RVS [11] has been one of the most realistic ways to simulate physical feeds.…”

“…A rigorous analysis of RVS can be found in [12]. Recently, a devised source independent model was proposed [10], which allows calculation of return loss to be independent of the cell height. This technique is used in this letter to increase the flexibility.…”