Radiation frequencies of ferrite patch antennas

The radiation frequencies of rectangular microstrip patch antenna deposited on ferrite substrate have been measured. Two different radiation modes were found whose frequencies behaved differently under the application of a biasing magnetic field. These two modes of radiation have been identified with a transverse mode whose radiation frequency increased with increasing magnetic field and a longitudinal mode whose radiation frequency decreased with the applied magnetic field. A theoretical model has been formulated for radiation of these two modes based on a multidomain configuration of the ferrite substrate. The theory compares reasonably well with the experiments.