A Differential SiGe HBT Doherty Power Amplifier for Automotive Radar at 79 GHz

In this paper, a differential Doherty power amplifier for automotive applications in a 130nm SiGe BiCMOS technology, featuring ft/fmax of 470/650 GHz, is presented. The amplifier achieves a measured, peak power added efficiency of 11.6% with 17.0dBm saturated output power at a frequency of 79 GHz. In the 6 dB power back-off, the proposed amplifier offers a power added efficiency of 6.1 %. For comparison, a reference Class-A amplifier has been designed that achieves an output power of 7.2dBm at the 6 dB power back-off with a power added efficiency of 1.8%. Compared to other state-of-the-art Doherty approaches, the proposed architecture first time proves the traditional transmission line-based impedance inversion in the automotive frequency range from 76 GHz to 81 GHz.

Automated summary

This paper presents a differential Doherty power amplifier designed for automotive applications using a 130nm SiGe BiCMOS technology. The amplifier achieves high power added efficiency at high frequencies and demonstrates, for the first time in the automotive frequency range, the impedance inversion based on transmission line.