An Efficient 0.4 THz Radiator with 20.6 dBm EIRP and 0.2% DC-to-THz Efficiency in 90nm SiGe BiCMOS

This paper presents an efficient 0.4 THz single-element radiator implemented in 90nm SiGe BiCMOS. It consists of a PIN diode quadrupler, where a mm-wave Colpitts oscillator at 100 GHz drives a PIN diode switching-reactance-multiplier into reverse recovery. Because of this, the PIN diode abruptly switches between two impedance states and produces strong harmonics. Harmonic injection locking is also presented in this work, where two quadrupler cells are mutually interlocked, and their fourth harmonic power at 0.4 THz combines at the antenna. The radiator achieves a peak EIRP of +20.6 dBm and -5.8 dBm radiated power at 398 GHz, with a 10.7 % tuning range, and consumes 130 mW DC power. This work has a DC-to-THz generation efficiency of 0.2%, the highest reported efficiency above 320 GHz, and achieves the highest power and EIRP generated by a single-element radiator.