Theory and analysis of electrode size optimization for capacitivemicrofabricated ultrasonic transducers

摘要

Theoretical analysis and computer simulations of capacitivenmicrofabricated ultrasonic transducers indicate that device performancencan be optimized through judicious patterning of electrodes. Thenconceptual basis of the analysis is that electrostatic force should benapplied only where it is most effective, such as at the center of ancircular membrane. If breakdown mechanisms are ignored, anninfinitesimally small electrode with an infinite bias voltage results innthe optimal transducer. A more realistic design example compares then3-dB bandwidths of a fully metalized transducer and a partiallynmetalized transducer, each tuned with a lossless Butterworth network. Itnis found that the bandwidth of the optimally metalized device is twicenthat of the fully metalized device