Size reduction and bandwidth enhancement of shorted annular ring (SAR) antenna

Size reduction of the antennas in personal wireless communications has become an important task for the antenna engineer due to the increasing popularity of compact handsets. In this paper, a new technique to reduce the size of a shorted annular ring (SAR) antenna is presented. This technique uses a capacitive loading structure that is analogous to a parallel plate capacitor. Increasing the antenna bandwidth and producing circular polarization are also presented.