Silicon micromachining techniques developed over the last few decades’ aid in precise control over nanometer scale structures. Using these techniques to fabricate transducer elements with small electrode spacing efficient and broadband ultrasonic air transducers can be made. In this paper frequency response profile of a circular capacitive micromachined ultrasonic transducer (CMUT) element with silicon nitride as the membrane material is analytically modelled and compared with FEM simulation results. It is observed that the resonance frequency is highly dependent on the membrane material and structural properties. Silicon nitride serves as an excellent material for generation and detection of ultrasonic waves in air. The results are compared with published experimental values and appreciable agreement is obtained.