SWITCHED-BEAM ANTENNA ARRAY WITH BROADSIDE BEAM FED BY MODIFIED BUTLER MATRIX FOR RADAR RECEIVER APPLICATION

A novel approach to the design of switched-beam antennas with broadside beam has been presented. The presented antenna utilizes a modified Butler matrix as a feeding network. The proposed feeding network consists of only two 3-dB/0/180 directional couplers, a 3-dB/90° directional coupler and a 180°phase shifter. Moreover, an innovative arrangement of the network has been proposed, which allows for avoiding any crossings in the network, and allows for achieving fully planar realization of a complete antenna. Measurement results of the designed three-beam antenna are shown, and also the application of the presented concept in a simple Doppler radar receiver is proposed, in which fixed phase shifters are eliminated. © 2014 Wiley Periodicals, Inc.