D. Gray et al., ELECTRONICALLY STEERABLE YAGI-UDA MICROSTRIP PATCH ANTENNA-ARRAY, IEEE transactions on antennas and propagation, 46(5), 1998, pp. 605-608
This paper describes a dual-frequency circularly polarized electronica
lly steerable microstrip patch antenna array suitable for land-mobile
communications. Based on a four-element Yagi-Uda patch antenna, the fo
ur antennas forming the array are located radially from a single squar
e reflector patch on a double-sided printed circuit board. The main lo
be of the array covers the elevation angles from 20 to 70 degrees with
a peak gain of 8.4 dBi at 1.54 GHz and 11.7 dBi at 1.62 GHz, Full azi
muthal coverage is possible by electronically switching between the fo
ur elements.