The Study of the Inductive Coil to the Acoustic Performance of Electromagnetic Driven Microspeaker

Electromagnetic driven MEMS speakers using Polydimethylsiloxane (PDMS) membrane have been investigated to obtain a better sound pressure level (SPL) respond in low frequency regime. The comparison between measure and COMSOL simulation of fabricated microspeakers shows that the copper coil and its electrical feedthrough have a strong effect on the rigidity of the membrane thus on the SPL. Without considering the feedthrough effect, wide bandwidth starting at low frequency can be obtained while the coil is placed in the centre of the membrane, whereas placing the coil close to the membrane border instead will give a better response in low frequency with feedthrough effect