USE OF A STEALTH BOUNDARY WITH FINITE DIFFERENCE FREQUENCY DOMAIN SIMULATIONS OF SIMPLE ANTENNA PROBLEMS

Abstract

A direct method for the numerical solution of Maxwell's equations in the frequency domain (sinusoidal steady state), for radiation problems of cylindrical symmetry, is incorporated into a finite difference program called HERZ, coded in FORTRAN. The termination of the fields on the outer boundary of the problem domain is accomplished via an absorptive layer, labelled a stealth layer, which attenuates the incident fields to insignificant amounts in a small computing space, without causing significant reflections that would disturb the near field solutions. No radiation boundary condition is specified on the problem domain, rather, the transmission of the fields to the stealth layer is optimized by specifying its electrical properties. To validate HERZ as a useful electromagnetic modeller for thin wire antennas, driving point admittances and surface current distributions for several configurations were compared to both theoretical and measured values, with good agreement. [Vol. 9, No. 1 (1994), pp 78-87]