A-2.5-dBm, 5.1%-Tuning-Range, 417-GHz Signal Source With Gate-to-Drain-Coupled Oscillator in 65-nm CMOS Process

This letter presents a novel subterahertz CMOS signal source with high output power. The proposed oscillators are mutually injected to align their frequencies and phases through a transformer that couples the gate and drain signals between the adjacent cores. The proposed architecture is implemented using the 65-nm CMOS technology. The measured peak output power is -2.5 dBm at 417 GHz while dissipating 108 mW. The proposed signal source shows the highest dc-to-RF efficiency (0.5%) and a wide tuning range (5.1%) among state-of-the-art signal sources above 400 GHz.