A multilayered magneto-electro-elastic membrane for focused audible sound beam generated through ultrasonic pressure fields

The generation of highly directive audible sound through ultrasonic pressure fields has some practical limitations due to high power consumption and strong focusing requirements. These limitations constitute a problem for including this technology in mobile devices with limited power and space. This paper offers construction of a new type of transducer specialized for these applications, which intends to tackle both limitations on power consumption and focusing. This is done through utilization of a multilayered membrane, which consists of piezoelectric and magnetostrictive materials that is exposed to a magnetic field for both, focusing and transduction purposes. Linear numerical simulations accounting for the interaction of the magneto-electro-elastic fields that provide the resonant frequency for ultrasonic transmission, and the optimum electromagnetic field for maximum curvature, are carried out using state-vector approach. Non-linear propagation of the ultrasound beam through the KZK equation is also included. A prototype transducer to check the validity of the observed results is under construction.