Wideband high efficiency high power GaN amplifiers using MIC and quasi-MMIC technologies

In this paper, the design and experimental results of a MIC Wideband (1-3GHz) and a balanced Quasi-MMIC wideband (2-4GHz), High Power GaN HEMT Power Amplifier (PA) are presented. The two designs, which use the same GaN process, are based on a theoretical study of the limitations in terms of trade-off between bandwidth and efficiency, derived from the Bode-Fano integrals, and applied to actual circuits. The MIC wideband PA, externally matched, generates an output CW power (P_out) greater than 40W, a Power Gain (G) higher than 9.5dB and a corresponding Power Added Efficiency (PAE) (Drain efficiency (DE)) ranged between 36-44% (40-48%) over the 1-3GHz bandwidth. A second amplifier, based on the same methodology, has been designed with a passive GaAs MMIC circuit technology. This fully and internally matched integrated amplifier size is lower than 420 mm². The power performances of this quasi-MMIC balanced PA are the following in the 2-4 GHz bandwidth: Pulsed CW P_out higher than 45W (50W between 2.1-4 GHz), G higher than 9.8dB and PAE (DE) ranged between 33-44% (38-50%). These results are ones of the best results published in terms of PAE performances and bandwidth tradeoffs.