The capacitive micromachined ultrasonic transducer (cMUT) has proved to be a viable alternative to the classical piezoelectric transducer in many practical applications like medical diagnostic and non-destructive testing. A cMUT consists of an array of closed electrostatic microcells obtained by surface micromachining a silicon substrate.In this paper, we present an electrostatic transducer made with an open-cell structure which shows many potential advantages over the closed-cell structure of the cMUT. Finite element model predictions together with experimental evidence demonstrate the viability of this approach to the electro-acoustic energy conversion in the MHz range.