Nonlinear lumped modelling of large-scale CMUT TOBE architectures

Capacitive micromachined ultrasonic transducers (CMUTs) promise many advantages over traditional piezoelectric transducers. One such advantage is the potential to construct large, cost-effective 2D arrays. However, due to wiring constraints, fully wired 2D arrays are impractical. An alternative approach, Top-Orthogonal-to-Bottom Electrode (TOBE) CMUT arrays, consist of only 2N wires for an array size of NxN. However, due to the size of the arrays and the many parameters influencing array performance, optimally designing a TOBE array is a significant challenge. In this paper we present large-scale TOBE CMUT simulations based on a nonlinear CMUT lumped-model. We analyze the different parasitic effects which limit dominant element isolation. These simulated result are then compared with measurements of TOBE arrays fabricated using a sacrificial release process.