A 0.32 THz SiGe 4x4 Imaging Array Using High-Efficiency On-Chip Antennas

Abstract

This paper presents a 0.32 THz 4x4 imaging array based on an advanced SiGe technology. Each pixel is composed of a high efficiency on-chip antenna meeting all metal-density rules, which is coupled to a SiGe detector and a low noise CMOS operational amplifier. A quartz superstrate is used on top of the imaging chip to improve the radiation efficiency. The array results in an average NEP of 34 pW/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> at an IF of 10-100 kHz for a detector bias current of 50-150 μA, a responsivity of 18 kV/W and a 3-dB bandwidth of 25 GHz. The power consumption is 2.4 mW/pixel. Extensive measurements are presented which show the challenges encountered in obtaining accurate measurements at THz frequencies using a quasi-optical set-up, and the decisions taken to quote the average NEP values.