BIMORPH-BASED PIEZOELECTRIC AIR ACOUSTIC TRANSDUCER - MODEL

A new type of bimorph-based piezoelectric air transducer with the work ing frequency range of 200-1000 Hz has recently been developed [B. Xu, Q. Zhang, V.D. Kugel, L.E. Cross, Piezoelectric air transducer for ac tive noise control, Proc. SPIE, 2717 (1996) 388-398]. In the present w ork, basic acoustic characteristics of this device and its piezoelectr ic elements are analyzed. To model the vibration spectrum of the trans ducer, a one-dimensional approach is developed where inertia, elastic and damping forces are included. Analytical equations describing mecha nical vibrations and electrical impedance of piezoelectric bimorph can tilevers under external forces are derived. In order to describe vario us losses in the transducer, complex piezoelectric, dielectric, and el astic constants are used. Results of the modeling are in good accord w ith experimental data. The suggested model can be used for device opti mization. (C) 1998 Elsevier Science S.A. All rights reserved.