Using COMSOL to Solve for Currents along a Thin-Wire Antenna Excited by a Lumped Source

A. Shoory, A. Smorgonskiy, and F. Vega
Electromagnetic Compatibility (EMC) group, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland

In this paper, we will present simulation results obtained using COMSOL RF module for the current along a wire antenna in both frequency and time domains. The structure is excited through a lumped (voltage or current) source at its center. For the frequency domain simulations we compare the results with the Numerical Electromagnetics Code (NEC-4) and for the time domain results we compare them with the prediction of the thin wire time domain (TWTD) code. Both codes are based on the method of moments (MoM) solutions of the governing electric field integral equation (EFIE). It will be shown that excellent agreement is found between current distributions along the wire antenna obtained using COMSOL in the frequency domain with NEC and in the time domain with TWTD. We will further discuss the effect of different excitation sources and some numerical issues necessary in COMSOL for obtaining the expected results. The objective of this paper is essentially to show the importance of such calibration mechanisms in order to be able to trust the results for more complicated structures.

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