Recent progress in switched beam single element antennas

This paper covers five different types of single element beam scanning antennas under electronic switch control. Firstly, a rectangular spiral antenna with shorting and open switches is presented. Following that, its polarization and other antenna parameter limitations are addressed. Then new structures, namely: star strip, star patch and square loop antennas, introduced to overcome the polarization problem in the spiral antenna, are covered. All these new antennas are symmetrical, and have 4 feeding points. When excited individually, these feeding points generate four tilted beams of the same characteristics in different quadrants, yielding a complete beam scanning antenna. The gains for these three antennas for each of the feed configurations are approximately 8.1 dBi and the polarization dominance is in the Eθ direction. Finally future work on implementing switches including MEMS on the ground plane of the antennas for switching the beam of the antennas is outlined. ©2008 IEEE.