A compact and light acoustic transducer using dielectric elastomer films for low frequency active noise cancellation

An acoustic transducer incorporating dielectric elastomer (DE) films, is proposed for active noise cancellation (ANC) setups inside the passenger compartment of ground and air vehicles, where compactness and lightness of the transducer along the effective generation of low frequency sound, are of primary concern. This transducer consists of two circular DE films in a push-pull configuration, fixed on a plastic frame. Application of electric field on a DE film, induces a change in thickness and surface area of the film, hence this configuration oscillates, generating sound. Meanwhile, the second film acts as a spring. In order to ensure effective generation of low frequency sound, the design of the transducer is based on its resonance frequency corresponding to the lower limit of the frequency range that it is able to generate. The total stiffness of the configuration depends in part on the pre-tension of the films, providing tuning ability of the resonance frequency. Simulations via finite element (FE) models confirm the accuracy of the analytical predictions.