A 1 k-Pixel Video Camera for 0.7–1.1 Terahertz Imaging Applications in 65-nm CMOS Richard Al Hadi , Student Member , IEEE , Hani Sherry , Student Member , IEEE , Janusz Grzyb, Ya n Z h a o, Member , IEEE, Wolfgang Förster, Hans M. Keller

Abstract

A 1 k-pixel camera chip for active terahertz video recording at room-temperature has been fully integrated in a 65-nm CMOS bulk process technology. The 32x32 pixel array con- sists of 1024 differential on-chip ring antennas coupled to NMOS direct detectors operated well-beyond their cutoff frequency based on the principle of distributed res istive self-mixing. It includes row and column select and integrate-and-dump circuitry capab le of capturing terahertz videos up to 500 fps. The camera chip has been packaged together with a 41.7-dBi silicon lens (measured at 856 GHz) in a 5x5x3 cm camera module. It is designed for continuous-wave illumination (no lock-in technique required). In this video-mode the camera ope rates up to 500 fps. At 856 GHz it achieves a responsivity of about 115 kV/W (incl. a 5 -dB VGA gain) and a total noise equivalent power ( )o fa b o u t 12 nW integrated over its 500-kHz video bandwidth. At a 5-kHz chopping frequency (non-video mode) a single pix el can provide a maximum responsivity of 140 kV/W (incl. a 5-dB VGA gain) and a minimum noise equivalent power ( )o f1 0 0 at 856 GHz. The wide-band antenna and pixel design achieves a 3-dB bandwidth of at least 790–960 GHz.