Antenna miniaturization using non-planar rings

The aim of this thesis is to investigate a method of reducing the size of a microstrip antenna's ground plane while at the same time preserving the good performance of a similar antenna on a much larger ground plane.; Preliminary research focused on the optimization of a shorted circular patch antenna on a large ground plane. The effects of truncating the ground plane are then studied.; This unique design consists of a metallic cylindrical ring attached to the perimeter of the ground plane to control the diffraction off the small ground plane. A smaller cylindrical ring, which is suspended off the ground plane, is mainly responsible for the improvement in performance. The analysis of the current distribution on this antenna leads to a hypothesis about the principle of operation of the antenna. To validate this hypothesis a different variation of the antenna was implemented. This variant replaces the inner cylindrical ring with two planar rings. (Abstract shortened by UMI.)...