A fully differential amplifier has been realized in 65 nm CMOS technology, which has demonstrated 20 dB peak gain, over 10 dB gain from 128–157 GHz, and 40 GHz positive gain range from 126 to 166 GHz. By using cascode architecture with high bulk voltage tied to the cascode devices in deep-Nwell, the amplifier ensures stability and can use 2 V supply reliably. By inserting a -matching network between cascode devices, it broadens the amplifier working range. This amplifier occupies 0.05 chip area, delivers over 5 dBm output power, and consumes 51 mA from a 2 V supply. To the authors’ best knowledge, this amplifier achieves the highest gain for CMOS amplifier beyond 100 GHz.