High-Gain 670-GHz Amplifier Circuits in InGaAs-on-Insulator HEMT Technology

In this letter, we report on the development of high-gain WR-1.5 amplifier circuits, utilizing a transferred-substrate InGaAs-on-insulator (InGaAs-OI) high-electron-mobility transistor (HEMT) technology on Si with 20-nm gate length. A six-stage and a nine-stage amplifier circuit are described, which are based on gain cells in cascode configuration. With more than 30 dB of measured gain in the frequency band of 660–700 GHz, the highest frequency of operation of transferred-substrate THz amplifiers is reported. These gain levels in excess of 30 dB, furthermore, correspond to the highest reported gain values and state-of-the-art performance around the targeted 670-GHz frequency band.