5F-3 A Matrix Transducer Design with Improved Image Quality and Acquisition Rate

Fully sampled 2D arrays present severe and conflicting requirements in element count, interconnect density, impedance, autonomous delay and amplitude control, high bandwidth at high dynamic range, and power consumption. cMUT transducer elements can have arbitrary dimensions machined directly above integrated circuits. We have designed a circuit that fits within the area of a 2D array element and achieves good signal fidelity at practical power dissipation, while limiting interconnect to 1D array complexity. It incorporates several novel techniques that simplify the process of preamplification, time-varying gain, baseband mixing, A/D conversion and beam formation. This achieves the design goals with highly parallel information retrieval. We also describe a novel transmitter that images at high volume rates with similar penetration to a traditional probe. Such performance is useful for visualizing fast-moving anatomical structures, such as heart valves, in 3D. We show how the transmitter and receiver form a bistatic probe suitable for clinical use. Experimental data are presented to evaluate the image quality obtained from the receiver circuit. We analyze its noise, distortion and time-gain control (TGC) performance. The new approach appears competitive with 1D probes in all basic imaging parameters, and permits 3D scanning We also investigate transmitter performance. Finally, we compare two- way signal-to-noise ratio and penetration with the state of the art.