Abstract: A wideband phase shifter for electrically adjustable antennas is proposed in this paper. Phase is changed by moving the dielectric. Partial impedance matching ensures that impedance of each branch will almost not be changed while the dielectric is being moved, so that power is distributed steadily to each port. Simulation and measurement indicate that the phase shifter can work within the frequency band 1.71GHz-2. 69GHz with VSWR<1.25, the transmission factor changing less than 1dB, and discrete phase less then 7.5% at the maximum phase shift. The phase shifter has advantages of wideband, universal application, compact arrangement, and small volume.