235-GHz Amplifier-Frequency-Multiplier Chain with Optimal Harmonic Impedance Matching Network in 40-nm CMOS

A 235-GHz amplifier-frequency-multiplier chain (AMC) composed of a cascode power amplifier (PA) and a frequency tripler (FT) for 6G applications is proposed in this work. The proposed FT integrates an optimal output harmonic impedance matching network, which can simultaneously achieve optimal impedance matching at both the fundamental and third harmonic frequencies, leading to a 5.7-dB enhancement in output power. Implemented in a 40-nm CMOS technology without ultra-thick metal layers available, the proposed AMC can deliver a peak output power of -2.7 dBm at 234 GHz with a 3-dB bandwidth from 218 to 252 GHz. Compared to prior works, the proposed AMC shows the highest figure of merit.