The study of Butler matrix BFN for four beams antenna system

In this paper, four beam patterns with frequency range from 1.7 GHz/spl sim/2.2 GHz is generated by a 4/spl times/2 antenna array. The directions of these beam patterns are /spl plusmn/12/spl deg/ /spl plusmn/40/spl deg/. The antenna directivity changes from 18 dBi to 18.7 dBi for these beam patterns. And the antenna gain changes from 10 dBi to 12.3 dBi. The H-plane 3 dB beamwidth changes from 21 degrees to 24.4 degrees. The test results are quite in agreement with that of simulation.