Chip: Broadband Oscillator-Free THz Pulse Generation and Radiation Based on Direct Digital-to-Impulse Architecture

Chip Fabricated: Broadband 0.03-1.1 THz signal generation and radiation

Based on an oscillator-free direct digital-to-impulse (D2I) architecture with a 1.9-ps FWHM and 130-GHz 3dB-BW (200-GHz 10dB-BW) centered at 160 GHz, we design Broadband 0.03-1.1 THz signal generation and radiation is demonstrated. The radiated pulse achieves a peak pulse EIRP of 19.2 dBm and peak pulse radiated power of 2.6 mW. An ON/OFF impulse-shaping technique is introduced and implemented to suppress ringing after the impulse and to increase DC-to-radiated efficiency. The frequency-comb spectrum of the radiated pulse train with 5.2-GHz repetition rate is measured up to 1.1 THz. For a distance of 4 cm, the measured received SNR at 1.0 THz and 1.1 THz is 28 dB and 22 dB respectively.

 

Results: Broadband Oscillator-Free THz Pulse Generation and Radiation Based on Direct Digital-to Impulse Architecture

A 10-dB spectral width of 2 Hz for the 1.1 THz tone is measured, demonstrating an extremely narrow spectral line width (two parts per trillion). Time-domain picosecond pulses are characterized using a custom femtosecond-laser-based THz-TDS measurement technique. Coherent spatial combining from two widely spaced chips is demonstrated. It is shown that the starting time of the combined radiated pulses is locked to the edge of the input digital trigger with an added timing jitter of 180 fs. The chip is fabricated in a 130nm SiGe BiCMOS process technology.

 

Publication

M. Assefzadeh and A. Babakhani, “Broadband Oscillator-Free THz Pulse Generation and Radiation Based on Direct Digital-to-Impulse Architecture”, submitted to IEEE Journal of Solid State Circuits, April 2017.