A Passive W-Band Imager in 65nm Bulk CMOS

A passive imager operating in the W-band around 90 GHz has been realized in a digital 65 nm CMOS process. The imager, occupying only 0.41 mm², integrates an SPDT switch with 4.2 dB loss and 25 dB isolation, a 5-stage telescopic cascode LNA with 27 dB gain at 90 GHz, and a W-band square-law detector, all consuming less than 33 mA from 1.2 V. The imager, when measured without the input SPDT, has a peak responsivity of over 200 kV/W, and a minimum NEP of less than 0.1 pW/VHz. With the input switch, it achieves a 90 kV/W responsivity and an NEP of 0.2 pW/VHz. This receiver represents the highest frequency imager to be implemented in standard CMOS with this level of integration.