A Squeeze-film Damping Model For The Circular Torsion Micro-resonators

Micro-resonators are typical devices in the field of MEMS,which are working around their nature frequency.Quality factor is a key indicator of micro-resonators,high quality factor means high resolution and high sensitivity.Squeeze-film damping as one of the air damping,plays an important role in the dynamic performance of MEMS devices.It is critical to predict the squeeze-film damping before the design of high quality micro-resonators.It has many works over MEMS torsion micro-resonators in the past,however,most of their works concentrate on rectangular plate,there has few works over circular torsion micro-mirrors,and no research in perforated circular torsion micro-mirrors.The fact is that circular plates have more universal application in MEMS devices,even surpass the rectangular plate,so it is significant to research the circular plate and perforated circular plate in MEMS micro-resonators.In this paper,the squeeze-film damping of circular plate and perforated circular plate are analyzed separately,the control equations of the gas in the gap are established and then convert to the form of cylindrical coordinate,then calculate the Reynolds equation by Bessel series methods,and get corresponding damping constants,spring constants,and quality factor.To verify the accuracy of the theoretical model,using the method of FEM to make simulations over two different models,and comparing the consequence of the numerical model and the analytical model.The influence of the radius and thickness of the circular plate,gas gap,frequency and ratio of the hole to the squeeze-film damping are also studied.