| This thesis is an investigation of two dimensional photonic bandgap structures (i.e. PBG's) and their applications in microstrip antennas and transmission lines. The photonic bandgap structures under study are ground plane PBG's and high impedance PBG's. The ground plane PBG's consist of perforations in the ground plane of microstrip structures. The perforations are placed in the ground plane of narrowband and wideband antennas as well as microstrip transmission lines. The overall effect of the ground plane perforations on the gain, bandwidth, resonant frequency and, the radiation pattern of the antennas are studied. For narrowband microstrip antennas, the perforations are used to prevent the excitation of the higher order modes while, for the wideband antennas the perforations are used to increase the bandwidth of the antennas. In the case of the microstrip transmission lines, the ground plane perforations are modified in order to create a wideband filter from the transmission line structure. The effective epsilon values are then calculated using a Matlab program for each filter structure. In addition to the ground plane PBG's, a second type of PBG consisting of metal patches with shorting vias (i.e. High Impedance PBG) is also investigated. The high impedance PBG is used in the design of the patch antennas on different dielectric structures. The effect of the PBG on the gain, radiation pattern, resonant frequency and, bandwidth of the antennas is studied. Each structure in the study is simulated using the commercial software Ansoft Ensemble which, is based on the method of moments (MoM). For seven cases the structures are fabricated and tested at the Antenna Laboratory at the University of Manitoba. For the fabricated cases the measured results are compared with the simulation data. |
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