A thin planar microstrip multibeam antenna system for capacity improvement of cellular radio

A thin 4 beam microstrip planar antenna is presented, for use in cellular radio systems, offering medium gain and the ability to be integrated into diversity schemes which conform to the GSM900 digital cellular system standard. The antenna, inclusive of beamformer, has a >10% impedance bandwidth, a minimum gain of 15.8 dB for each beam and has dimensions 710/spl times/800/spl times/12 mm.