FEM Analysis of Ultrasonic Transducer with Square and Circular Diaphragm

The objective of the paper is to design a Microelectronic Mechanical Systems(MEMS) based Capacitive Micromachined Ultrasonic Transducer (CMUT) which has been found to be superior in terms of bandwidth, transduction efficiency and array fabrication as compared to conventional piezoelectric transducers. With the years CMUT has been shown with different element geometries and fabrication techniques, however the optimization techniques and the application areas for the device persist. In this paper CMUT is simulated in COMSOL with Square and Circular diaphragm. FEM analysis is being carried out considering the same area for both the geometries in 3D.CMUT dynamics have been modeled by combining the Electrostatic module, Solid Mechanics Module and Mesh modules in COMSOL. The distributed stress and electric field are measured as function of time. This gives the exact comparison for the Eigen frequency, pull in voltage, deflection with applied DC bias and deflection of the diaphragm with AC superimposed on DC considering the isotropic Silicon as the diaphragm material. This simulation work provides results for the researcher to conclude on the geometry of the device prior to fabrication.