Novel phase shifters using short-circuited cross-slotted patch resonator

In this paper, a novel phase shifter using short-circuited cross-slotted patch resonator is presented. After inserting the via holes along the symmetrical plane patch, a wide three-pole bandpass response is realized for the signal transmission. Once the size of patch resonator is fixed, the location of these transmission poles can be well controlled by adjusting the loaded cross slots. For the phase differences from 30° to 90°, the fractional bandwidth for the phase deviation of ±5° achieves up to 61.4%. Finally, a 45° phase shifter operated at 3.5 GHz is designed and validated experimentally. The measured results show a wide three-pole matching bandpass response, and a 10.5% fractional bandwidth for phase deviation of ±5°.