Revisiting power vs. bandwidth in broadband CW amplifiers by exploring 100 V bias operation

Broadband impedance matching for band-pass RF power amplifiers targeting Software Defined Radios (SDR) is reviewed with emphasis on the power supply voltage and how higher voltage operation could improve power versus bandwidth. Measured data on a 100 watts CW GaN amplifier operating at 100 V over the 500 MHz-2 GHz frequency band are shown to support the analysis. Results show that amplifier operation at increased bias can indeed result in higher power over broad bandwidth for SDR applications. However, success strongly depends on improvements in the 100 V RF transistor technology.