DESIGN OF A SILICON MICROPHONE WITH DIFFERENTIAL READ-OUT OF A SEALEDDOUBLE PARALLEL-PLATE CAPACITOR

A new design of a sealed capacitive microphone with differential capac itive read-out and high sensitivity is presented, The design allows fo r higher electrical bias fields and thereby higher sensitivities compa red to ordinary capacitive microphones. The bias field can be further increased if force balancing is used, which is very simple to implemen t with this design. To avoid too high bias voltages, the air gap is re duced. The design is based on analytical modelling and finite-element calculations.