An efficient, low-profile antenna employing lossy magneto-dielectric materials

Abstract

It has been shown that a magnetic core in a loop antenna excludes energy from the interior reducing radiation Q and that a core with magnetic losses still provides this reduction of stored energy without excessive dissipation provided that the magnitude of the complex permeability is sufficiently large. We present a broadband, low-loss, low-profile antenna based on a lossy magneto-dielectric material, a Ni-Zn ferrite operating in its dispersion region. The antenna behaves as a magnetic dipole and a radiation efficiency of almost 65 % is obtained at a frequency for which the loss tangent of the material is greater than 10.