A 210-320GHz Power-Combining Distributed Frequency Doubler with Tuned Pre-amplification in 0.13μm SiGe BiCMOS

The paper presents the theory and design of a broadband distributed frequency doubler operating across 210320 GHz. We introduce power combining within the distributed structure, with two sets of distributed doublers driving a common transmission-line load. Passband characteristics over the desired frequency range are introduced with stagger-tuned narrowband pre-amplifier stages employed in each unit cell of the 15-stage doubler, which extends flat output power beyond $f_{T}$. The 3 V prototype in 0.13 um SiGe BiCMOS ($f_{T} / f_{M A X} 300 / 450 \mathrm{GHz}$) delivers 3.6 dBm power at 300 GHz to a $50 \Omega$ load, with a conversion gain of 13.6 dB. It is the highest reported output power at 300 GHz for Silicon and InP-HBT based frequency multipliers.