A SIMPLE SWITCHED BEAMFORMING NETWORK FOR FOUR-BEAM BUTLER MATRIX

Abstract

A simple switched beamforming network, with one 90 degrees hybrid, two switches, and delay, lines is designed. By controlling the switches. the antenna can produce four beams with the phase differences between adjacent radiating elements being +/- 135 degrees and +/- 45 degrees. The proposed feed network is simple, provides a tapered amplitude distribution, and has the same phase characteristics as the four-beam Butler matrix feed network. The measured S11 of the proposed antenna is less than - 10 dB at the operating frequency of 11.2 GHz. When switch 1 is in the "on" position and switch 2 is in the "Off" Position, or when both switches are in the "on" position, the measured radiation pattern shows that the scan angles are -12 degrees and +35 degrees. The proposed array antenna has the advantage of low, cost, small volume, and easy fabrication. (c) 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1413-1416, 2009: Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24352