45-GHz and 60-GHz 90 nm CMOS power amplifiers with a fully symmetrical 8-way transformer power combiner

In this paper, 45 GHz and GHz power amplifiers (PAs) with high output power have been successfully designed by using 90 nm CMOS process. The 45 GIIz (60 GIIz) PA consists of two (four) differential stages. The sizes of transistors have been designed in an appropriate way so as to trade-off gain, efficiency and stability. Due to limited supply voltage and low breakdown voltage of CMOS MOSFET compared with the traditional III-V technologies, the technique of power combining has been applied to achieve a high output power. In particular, a novel 8-way distributed active transformer power combiner has been proposed for realizing such mm-wave PA. The proposed transformer combiner with a fully symmetrical layout can improve its input impedance balance at mm-wave frequency regime significantly. Taking its advantages of this novel transformer based power combiner, our realized 45 GHz (60 GHz) mm-wave PA has achieved the gain of 20.3 dB (16.8 dB), the maximum PAR of 14.5% (13.4%) and the saturated output power of 21 dBm (21 dBm) with the 1.2 V supply voltage.