GaAs X-band high efficiency (>65%) Broadband (>30%) amplifier MMIC based on the Class B to Class J continuum

This paper demonstrates, for the first time, that the Class B to Class J concept can be successfully extended to X-band operation. X band power amplifiers with >;30% bandwidth are required for a wide range of emerging applications where achieving optimal electrical efficiency is a key system driver. High efficiency is ordinarily achieved using circuit elements resonant at harmonic frequencies that are inherently narrowband in operation. The Class B to Class J continuum of modes, exploited here, offers Class B levels of efficiency over a continuum of impedance matching conditions, making wider bandwidth designs more feasible. This paper presents measurements of devices and MMIC designs which were undertaken to systematically use the continuum of modes for the first time at X-band. The 0.5W MMIC fabricated using a GaAs pHEMT process yields above 65% drain efficiency over >;30% bandwidth.