A 500 GHz Receiver Front-End for Biological Detection in 40-nm CMOS Technology

This paper designs a front-end receiver circuit for bio-detection applications based on the 40 nm CMOS process. The circuit consists of a 500 GHz mixer and a 20 GHz low-noise amplifier (LNA), adopting a mixer-first structure in this design. The mixer works at 500 GHz, utilizing a four-harmonic mixing structure to effectively reduce the frequency of the local oscillator (LO) signal. Due to the considerable losses introduced by terahertz mixer, the LNA is utilized to amplify the intermediate frequency (IF) signal. The LNA uses a two-stage cascode structure, and utilizes the transformers for matching. With an input LO signal power of 2.4 dBm, the front-end receiver achieves a minimum conversion loss of 9 dB and a minimum noise figure of 35 dB. The chip occupies 1.1 × 0.48 mm²dissipating 21.5 mW from a 0.9 V voltage supply.