Theoretical evaluation of resonant frequencies of a hemispherical-circular microstrip antenna

We present a novel and simple method of deducing the resonant frequencies for a circular patch antenna mounted on a sphere. A particular case in this class of antenna namely hemispherical-circular antenna (/spl theta/=90 deg.) is investigated. It is shown that dominant mode resonance is tuned up in frequency by approximately 20%. The validity of this method is also evaluated. This class of MSA can be a very useful tool for EMC applications since this has a significantly high polarisation purity compared to other conformal antennas like planar circular patch antennas.