Wouter Steyaert

A 0.54 THz Signal Generator in 40 nm Bulk CMOS With 22 GHz Tuning Range and Integrated Planar Antenna

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 harmonic is coupled via a transformer to the output. The developed techniques are implemented on two different chips: one with a probe pad for on-wafer measurements 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, resulting 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.

A 0.54 THz signal generator in 40 nm bulk CMOS with 22 GHz tuning range

This work presents a 540 GHz signal generator consisting of a LC-VCO with buffer, implemented in a 40 nm bulk CMOS technology. The buffer is optimized for non-linear operation, to maximize the third harmonic generation at 540 GHz. The third harmonic is coupled to the load by a transformer. To accurately measure the output power, a WR-1.5 probe has been used. The output power is -31 dBm at 543 GHz, for 16.8 mW of DC power consumption. The output frequency can be tuned from 561.5 GHz to 539.6 GHz, resulting in a 21.9 GHz tuning range,the highest reported so far for CMOS THz oscillators. The 3-dB output bandwidth is 5.5 GHz.

A THz signal source with integrated antenna for non-destructive testing in 28nm bulk CMOS

This work presents two fully integrated above-fmax signal sources (570GHz and 600GHz) with on-chip antenna, implemented in a 28nm bulk CMOS technology. A VCO generates a signal at the fundamental frequency, which drives a non-linear amplifier to generate the wanted third harmonic above. The above-fmax third harmonic signal is coupled directly to a folded dipole antenna (570GHz, -34.3dBm EIRP) or to a collinear dipole antenna through a transformer (600GHz, -43dBm EIRP). Both sources provide a wide tuning range and 3dB output power bandwidth while maintaining a compact layout footprint. These are the highest reported fully integrated signal sources in bulk CMOS with on-chip antennas and used as transmitters in a THz imaging setup for non-destructive quality control.

A 230.5–238.8-GHz magnetically coupled triple-push oscillator with inductive tuning for data transmission in 45-nm CMOS

A scalable coupled triple-push voltage-controlled oscillator (VCO) based on inductor switching is analyzed and proposed for data transmission via binary frequency shift keying (BFSK) at sub-terahertz (THz) frequencies in 45nm predictive CMOS bulk technology. Inductive switching enables better quality factors above 100GHz due to the increasing losses associated with capacitors. Novel inductor switching technique is proposed in order to enable easy coupling and wide tuning range at the same time for data transmission above 200GHz. Simulation results suggests that 12.3Gbps data rate is possible to be achieved. −12.4dBm output power is achieved with only a variation of 0.2dB in 7.4GHz bandwidth. Oscillation frequency can be tuned from 224GHz to 231.4GHz for single core VCO. Power consumption is 15.5mW for one core. The proposed oscillator is easy to magnetically couple from gate inductors to generate higher output powers depending on the transmission distance and losses. Two coupled VCO is implemented as a proof of concept and reaches up to −10.5dBm output power with a bandwidth of 8.25GHz. To the authors knowledge, this is the first VCO above 200GHz that uses inductor switching and BFSK.