A monolithic low phase noise power oscillator using 0.35 um GaN/Al_0.27Ga_0.73N MMIC process

Based on the 0.35 um GaN/Al_0.27Ga_0.73 N high electron mobility transistor (HEMT) microwave monolithic integrated circuit (MMIC) process, a monolithic power oscillator has been designed, fabricated and measured for the first time. By connecting a common-source power amplifier (PA) with feedback network, the oscillation of amplifier is created, thus the function of an oscillator can be realised. The measured output power and efficiency of the fabricated oscillator are 22.8 dBm and 14.9%, respectively, at 1.29 GHz with a drain bias voltage of 10 V. Due to the high output power and inherent advantages of the GaN materials for the device design, the phase noise is measured to be −127.68 dBc/Hz at the offset frequency of 1 MHz, the lowest reported so far in oscillators using GaN MMIC technology. The chip size is 1 × 1 mm².