An Investigation of InP DHBT Doherty Amplifier for Enhanced Efficiency in D-Band

this work, a Doherty amplifier (DA) implemented in an InP DHBT technology is investigated for enhanced power-added-efficiency (PAE) and 6-dB power-back-off (PBO) efficiency in D-Band. The DA is implemented with standard common-emitter power cells, as well as power cells with enhanced gain. The gain enhancement is achieved by adding driver stages or by implementing power cells in stacked topology. The best achieved simulated performance of a DA circuit implemented using a Class-AB main amplifier and Class-C auxiliary amplifier demonstrates a gain of 3.5 dB, peak PAE of 29.4 percent, and 6−dB PBO efficiency of 11.1 percent, at 140 GHz. In comparison, a simulated performance of a single-stage common-emitter Class-AB power amplifier demonstrates a gain of 5.1 dB, peak PAE of 33.1 percent, and 6-dB PBO efficiency of 14.8 percent, showing no advantage of using DA for high dynamic range signal amplification in D-Band.