Wideband microstrip antennas using electromagnetic bandgap structures

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Kashani, Marjan
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In this thesis, I performed a study on the electromagnetic behaviors of an Electromagnetic Bandgap (EBG) structure with a specific set of parameters, and explored the effects of the geometrical parameters on its bandgap, which can be a stepping stone for designing future EBG structures with desired electromagnetic bandgaps. Later, the performance of a microstrip patch antenna when its ground plane is replaced by a lattice of the studied EBG units is investigated. This led to a noticeable bandwidth and gain enhancement, which motivated me to perform a parameter study to seek further bandwidth improvement. No restriction was placed on the range of parameters, and wider band antennas were observed when parameters fell outside the band gap requirements. Furthermore, I developed methods and designs that can be used to reduce the antenna size and weight by applying some structural modifications. I introduced two antennas, which I named “the puck antenna” and “suspended EBG-backed antenna”. The presented simulation results describe the performance of these antennas. The use of an EBG structure as the ground plane of a microstrip patch antenna is shown here to enhance the gain of the antenna. This motivated me to look for further gain enhancement by placing a dielectric cover on top of the antenna, referred to as “superstrate”. In the literature, the gain enhancement effect of the superstrate on different antennas including microstrip patch antennas has been confirmed. But using a superstrate on an EBG-backed microstrip patch antenna can be considered as another novelty of this thesis project, which led to further gain enhancement.
Electromagnetic Bandgap Structure, Microstrip Patch Antennas, Wideband Antennas, Impedance Bandwidth Enhancement, Directivity Enhancement
M. Kashani, L. Shafai, and D. Isleifson, “Performance improvement of a microstrip patch antenna on an EBG structure,”(in press) IEEE AP-S URSI 2020 Proceedings, 2020