Higher phase-tunable phase shifters using DGS termination loads

New phase shifters with higher phase shift values are presented using defected ground structures (DGSs). The varactor diodes are mounted on DGSs of termination loads to control the large phase variation of the DGS at resonance. Two types of phase shifters are implemented with a branch-line and a coupled line hybrid. The experimental results of the proposed phase shifters show 135% and 221% increases in maximum phase shifts, respectively, compared with those of conventional ones.