Finite element study of cross coupling in 1-D capacitive micromachined ultrasonic transducer arrays

Many important issues in transducer array design, such as cross-talk, can be investigated using the finite element (FE) method. In this paper, a 2-D finite element model is constructed to analyze the interaction between the elements of 1-D capacitive micromachined ultrasonic transducer (CMUT) arrays. A specific meshing scheme is developed, that allows to simulate a large structure immersed in a fluid, including several cells located on a thick substrate with a backing. The directivity pattern of an individual array element is calculated in pulsed operation directly from FE results, giving an indication of the entity of cross coupling. Several variations on the array design are then explored to reduce the level of cross-talk.