Low Phase-Noise 5 GHz AlGaN/GaN HEMT Oscillator Integrated with BaxSr1-xTiO3 Thin Films

A C-band MMIC oscillator in GaN HEMT technology with BaxSr1-xTiO3 (BST) film capacitors integrated as DC block capacitors has been designed, fabricated and characterized. The lumped LC resonator works with the common gate HEMT to generate negative resistance. The oscillator, based on AlGaN/GaN HEMT with 0.7um gate length and 200um gate width, delivers 20.5 dBm output power when bias at Vds = 15 V and Vgs = -3 V, with dc- to-RF efficiency of 12.5%. Phase noise was measured to be - 105 dBc/Hz at 100 kHz offset from 5.3 GHz carrier. The results show that AlGaN/GaN HEMTs are attractive to both high power and low noise microwave source application. Index Terms — GaN, high electron-mobility transistor (HEMT), BaSrTiO3 (BST), monolithic-microwave integrated-circuit (MMIC), oscillator, phase noise.