Murat Dogrul

Date of Award


Document Type


Degree Name

Master of Science in Electrical Engineering


Department of Electrical and Computer Engineering

First Advisor

Peter J. Collins, PhD


Gain and bandwidth metrics of broad-band low-profile antennas severely deteriorate when they are placed conformally onto the conductive skins of air, sea, and ground platforms. This detrimental effect is primarily due to out-of-phase reflections from the conductive body interfering with the antenna’s self radiation. Furthermore, lateral waves launched by the antenna couple into the thin substrate placed between the antenna and the platform, giving rise to surface waves resulting in significant diffraction from the edges of the substrate. To remedy these two major mechanisms degrading antenna performance, high impedance ground planes (HIGP) were designed. HIGPs made of a 2-dimensional periodic arrangement of a mushroom structure not only provide perfect-magnetic-conductor (PMC)-like reflection but also suppress the surface waves within the stop-band of the substrate modes. This thesis presents new geometrical shape HIGP-antenna designs and optimizations. Dipole antenna, log periodic antenna and finally bow-tie antennas are used in the research. Operating frequency bands of these antennas over different types of optimized HIGP’s are investigated. Multi-scale HIGP and antenna designs are introduced in the final part of the thesis. Broadband nature of the HIGP-antenna designs is increased by using multi-scale HIGP.

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