Phase-Controlled Beamforming Network applied to Linear Arrays

This paper describes a 1×4 reconfigurable radio- frequency (RF) feed network used to perform beamforming in linear arrays. The utilized beamforming network, based on a four-way power divider, four branch-line couplers and eight variable phase shifters, is able to distribute its RF input signal among its output ports with variable amplitudes and phases. In this paper, the network is connected to a linear array composed of four microstrip patch antennas, and it is used to perform the following functions: modify the half-power beamwidth of the antenna, steer the antenna beam electronically, and, more generally, perform beam shaping. The basic theory of the feed network is reported, and auxiliary variables are introduced to better clarify the circuit behavior. Finally, the obtained experimental results are illustrated and discussed.