| This thesis provides an investigation of high impedance electromagnetic bandgap (EBG) structures as a substrate for applications in microstrip patch antennas. First, the basic background theory of microstrip patch antennas and electromagnetic bandgap structures is reviewed. The equations for design of patch antennas and the basics of EBG structures are introduced. Then, microstrip patch antennas using high impedance EBG substrates, within the bandgaps are investigated. The bandgaps of the EBG structure are found, and patch antennas are designed to work within these bandgaps, to study their properties. Both single layer and two layer EBG structures are used in this study, and their effects on the resonant frequency, minimum S11, bandwidth, radiation patterns and gain of the antennas are investigated. Then, investigations are conducted for microstrip patch antennas outside the bandgaps, both lower and higher frequency bands. Again, the effects of the EBGs on the resonant frequency, minimum S11, bandwidth, radiation patterns and gain of the antennas are investigated. The structures are simulated using the commercial software Ansoft Ensemble which is based on the method of moments (MoM). In order to confirm the simulation results, several antennas are fabricated in the Antenna Laboratory and the Machine Shop at the University of Manitoba. The measured results agree well with the simulation data. |
