A 254 GHz CMOS Transmitter With VCO-Q Modulation

This letter presents a transmitter at 254 GHz, which uses both amplitude and frequency changes of a transformer-based VCO output by control voltage. Amplitude modulation is achieved by VCO-Q modulation of the VCO with varactor control voltage (V
_CONT
). Wide-deviation frequency modulation is also achieved due to its wide tuning range, which improves the amplitude modulation by filtering out a low-amplitude band at a receiver. It is fabricated by a 65 nm CMOS process and demonstrates a high data rate of over 10 Gb/s and a low dc power consumption of 23 mW. The amplitude modulation is improved by 9.7 dB with an implemented receiver.