Design of a 360° Continuously Variable Phase Shifter using Improved Regression Algorithm for X-band Phased Array Applications

In this paper, a variable phase shifter with 360 degrees continuous phase shift range for the X-band phased array applications is presented. The system consists of a branchline coupler, a pair of variable reflection loads using varactor diodes and a switched line topology. The proposed reflective loads result in compact design and require only one control voltage for the varactors which results in simplified control circuit. An algorithm for the control circuit to predict the bias voltage for the required beam steering is also presented. This was further verified by designing and simulating a 4x4 antenna array in Ansys HFSS. The proposed phase shifter achieves an average insertion loss of 4.6 dB and return losses better than 12 dB at 10 GHz with a fractional bandwidth above 15% in simulation.