The circular cavity for antennas, periodic structures, and power combiners

Circular cylindrical cavity resonators have been studied in three configurations. First, a slot antenna backed by a circular cylindrical cavity was analyzed. The resonant frequency of the cavity is found using power conservation considerations. Three resonant frequencies were found. The first resonance occurred because the slot resonated on its own. The second resonance was a closed cavity resonance. The third resonance was due to the coupled slot and cavity resonance. The theoretical results were found to be within 2% of experimental results for most cases. The theory was used to predict the resonant frequency for a structure fed through the cavity sidewall. The antenna pattern for a dielectric filled slot was also examined. The dielectric was shown to lower the operation frequency and had little effect on the shape of the antenna pattern. A periodic string of resonant cavities was the second structure studied. The cavity string was examined using cavity perturbation theory and the Bethe small aperture theory. A string of...