Electronically Reconfigurable Two-Stage Schiffman Phase Shifter for Ku Band Beam Steering Applications

An electronically reconfigurable phase shifter using two Schiffman sections is performed for beam steering applications in Ku band. The proposed phase shifter consists of only two cascaded coupled-line sections with the reference line removed. This circuit is loaded by varactor diodes that ensure its tunability over a wide bandwidth. By supplying these varactor diodes with suitable bias voltages, a phase shift is continuously adjusted and reached up to 168° at 12.7 GHz with low insertion losses according to the simulations. Thus, the proposed two-stage phase shifter is able to reach a beam steering angle of 28.6° at 12.7 GHz with only one control voltage. The proposed structure exhibits that our phase shifter has a compact size and a large phase shifting range throughout the Ku band. The tunable phase shifter is prototyped and the measurement results are presented.