Cmos Controlled Ghz Ultrasonic Impedance Imager

This paper presents a demonstration of CMOS driven 1-2 GHz ultrasonic imager that can be monolithically integrated in a single-chip and operate at 1.5V battery voltages. The pulse transmit/receive operation of a single AlN transducer pixel driven by custom 180nm CMOS RF circuits is demonstrated. The pixel transducer is scanned in two dimensions to image fingerprints and leaves with 254 dpi resolution. Based on a single pixel imaging time, frame rate is estimated to be 500 fps at 13.6 μJ/frame. The contrast of returned signal between rubber and air is 3.3:1 for dry rubber and 1.5:1 for wet rubber. This work shows a pathway towards single chip GHz ultrasonic imager.