Antenna size reduction using Yagi-Uda loops and shorted circular patches

The reduction in the size of antennas for personal communication systems applications is a research area that is receiving lots of attention. The literature concentrates on reducing the size of microstrip patches however most of these antenna types require a large ground plane. Reducing the size of the ground plane has adverse affects on the antenna. To counter these affects a novel antenna type is presented. This antenna uses a shorted circular patch surrounded with nonplanar rings. These rings allow a reduction in the ground plane to a radius of less than 0.23 /spl lambda/ and improve its radiation characteristics. Through examination of the currents on the antenna, the principle of operation is explained based on a Yagi-Uda like array concept. Further theoretical and experimental examination confirms the above explanation.