Design and optimization of a high efficiency 60 GHz SiGe-HBT power amplifier

This work presents the design and optimization strategies of a 60 GHz monolithic power amplifier. The circuit has been implemented utilizing an advanced 0.25 mu m SiGe-HBT technology, featuring npn transistors with f(T) and f(max) approximate to 200 GHz. The technique used to achieve a minimum difference between the output power under 1 dB compression and saturated output power is explained. Following this, the analysis of supply voltage and bias current optimization is presented along with the simulation results. The developed two cascode power amplifiers show a measured small signal gain of 18.8 dB and an output power of 14.5 dBm under I dB gain compression at 61 GHz. At this frequency, the saturated output power is 15.5 dBm and the peak power added efficiency is 19.7 %. The power amplifier presented here has the highest power added efficiency so far, compared to all SiGe-HBT based power amplifiers in the 60 GHz frequency range.