A High Efficiency Q-band MMIC GaN Power Amplifier for Space Applications

This paper describes the design methodology and the On-Wafer (OW) measurement results of three Q-band four-stage MMIC High Power Amplifiers (HPA-LB, HPA-MB & HPA-HB) operating respectively in the 35-41GHz, 37-42GHz and 38-43GHz bandwidths. A Single-Ended HPA topology is considered (SE-HPA). These demonstrators are fabricated in 150-nm HEMT Gallium Nitride on Silicon Carbide technology (AlGaN/GaN on 70μm SiC substrate) for space applications, and thus considering space de-ratings. The main aim of this realization was the achievement of high output power associated with a high Power Added Efficiency. To obtain a good compromise between output power and PAE, a multi harmonic tuning approach of load and source impedances has been applied.The On-Wafer measured power results under pulsed wave signal of all SE-HPAs demonstrate a maximum output power (POUT) higher than 8W (39dBm) with 25% Power Added Efficiency (PAE) and more than 28dB of insertion gain (GI) in the overall frequency band of the interest.