A 0.54 THz Signal Generator in 40 nm Bulk CMOS With 22 GHz Tuning Range and Integrated Planar Antenna Wouter Steyaert, Student Member , IEEE

Abstract

This work presents the design and measurements of a 0.54 THz signal generator implemented in a 40 nm bulk CMOS technology. An LC-VCO operating at 180 GHz is connected to a nonlinear buffer, which is designed to generate the wanted third harmonic at 540 GHz. The third ha rmonic is coupled via a trans- former to the output. The develop ed techniques are implemented on t w od i f f e r e n tc h i p s :o n ew i t hap r o b ep a df o ro n - w a f e rm e a - surements and one with an on-chip planar dipole. The measured peak output power using a WR-1.5 probe is 31 dBm at 543 GHz, for 16.8 mW of dc power consumption. By changing value of the parasitic I-MOS varactors of the LC-VCO (“parasitic tuning”), the output frequency can be tuned from 561.5 to 539.6 GHz, re- sulting in a 21.9 GHz tuning range, which is the highest reported so far for CMOS THz oscillators. The 3-dB output bandwidth is 5.5 GHz. The 540 GHz signal generator with on-chip antenna is used for THz imaging without the use of substrate or focusing lenses, demonstrating some of the capabilities of CMOS for low- cost, mass-produced THz imagers.