692 GHz High-Efficiency Compact-Size InP-Based Fundamental RTD Oscillator

A terahertz (THz) fundamental oscillator IC with high efficiency and compact chip size based on an indium phosphide (InP)-based resonant tunneling diode (RTD) is proposed. The oscillator is designed by utilizing a low-frequency bias stabilizer, along with utilizing a negative differential resistance oscillator topology. The oscillator is fabricated by using an InP monolithic THz integrated circuit multilayer process. The fabricated oscillator shows a high dc-to-RF power efficiency (eta) of 0.274 % with a low dc power consumption of 3.4 mW and an RF output power of 9.3 mu W at an oscillation frequency of 692 GHz. The IC exhibits a chip size of 300 x 380 mu m(2) excluding the measurement pads. The achieved eta and chip size are good values among THz oscillators above 500 GHz reported to date.