High-Power X-Band GaN Switched-Filter Phase Shifter

This paper presents a high-power switched-filter GaN phase shifter, designed for X-band and offering good performance from 8-16 GHz. The manufactured 0 degrees/22.5 degrees switched-filter phase shifter has much wider bandwidth than is typically found with this configuration, while maintaining low insertion loss (< 2 dB), good return loss (> 11.15 dB) and an amplitude imbalance of less than 1.03 dB across X-band. The 1 dB compression point was higher than laboratory equipment was able to measure (> 38 dBm) and the phase shifter MMIC exhibited an IIP3 higher than 46 dBm. The proposed high-power phase shifter has been fabricated in a 0.5 mu m GaN HEMT process and was designed using an accurate, customized switch FET model.