A COMPACT DUAL-POLARIZED BROADBAND ANTENNA WITH HYBRID BEAM-FORMING CAPABILITIES

A broadband dual-polarized four-port (DPFP) antenna is presented in this paper, which consists of a radiation element and a feed network. It is very compact in size, with the diameter of 150.0mm and the height of 47.0mm, with the following unique properties: (1) it has hybrid beam-forming capability and operates at two modes, which depends on its excitation; (2) its operating frequency range is from 0.96 to1.78GHz, and the return loss is about 10dB; (3) its insertion loss is (3 § 0:5)dB, with its balanced power splitting over the relative bandwidths of 37% at Mode 1 (180 - § 5 - phase shifting) and 55% at Mode 2 (§5 - phase shifting), respectively; (4) an isolation of 30dB at Mode 1 is obtained between the dual polarized ports, with the gain of 7.6dBi and 42 - of the 3dB-bandwidth at 1.25GHz; and (5) the gain difierence between Modes 1 and 2 is about 7dB, within the angle of i15 - • µ • 15 - for the same polarization at 1.25GHz. For the application of DPFP, a hybrid beam forming algorithm is proposed with an angular precision of 7 - and is validated by measurement.