Electrically unbiased driven airborne capacitive micromachined ultrasonic transducer design

Abstract

We present a design method for airborne capacitive micromachined ultrasonic transducers (CMUT). We use an equivalent lumped element circuit to model both electrical and mechanical properties of CMUT and analyze it in frequency domain using harmonic balance approach. We use this method to design CMUTs for large transmitted power generation at low drive voltage amplitude. We determine the dimensions of an airborne CMUT using the proposed method that works at 30 kHz with 5 mm radius, 240 μm membrane thickness and 11.8 μm effective gap height. The CMUT is designed such that an atmospheric depression of 70% of effective gap height is maintained. © 2012 IEEE.