Equivalent Circuit for Dipole Antennas in a Lossy Medium

Abstract

A lumped-parameter equivalent circuit for an uninsulated antenna in a lossy medium is derived from the impedance of the same antenna in air. Consisting of four frequency-independent elements and four elements related to loss tangent and frequency, the equivalent circuit is sufficiently accurate for a broadband simulation including the resonant frequency at which antennas are generally designed to operate. Acceptable relative errors are demonstrated by comparing the results of the equivalent circuit with simulated data obtained from a full wave analysis. The equivalent circuit can be used to replace complex antenna models in lossy media and quantify the effect of the loss on antenna performance.