Multiple annular ring capacitive micromachined ultrasonic transducer arrays for forward-looking intravascular ultrasound imaging catheters

We investigate multiple-annular-ring CMUT array configuration for forward-looking intravascular ultrasound (FL-IVUS) imaging. This configuration has the potential for independent optimization of each ring and uses the silicon area more effectively without any particular drawback. We designed and fabricated a sample 1mm diameter dual annular ring CMUT test array which consists of 24 transmit and 32 receive elements. For imaging experiments, we designed IC chips that contain 8 transimpedance amplifiers, a multiplexer and a buffer. The real time-pulse echo experiments obtained with designed IC electronics show 26dB Signal to Noise Ratio (SNR) from a 3.5 mm away aluminum reflector in oil. This paper presents our first efforts in obtaining real time imaging with designed IC chips which is one step before CMUT on CMOS implementation.