A New Method for Real-Time Measuring the Temperature-Dependent Dielectric Constant of the Silicone Oil

This paper presents a new method for real-time measuring the temperature-dependent relative dielectric constant and the thermal expansion coefficient of the silicone oil by using a low-cost microelectromechanical systems (MEMS) structure. The relative dielectric constant of the silicone oil can be obtained by measuring the capacitance of an MEMS temperature sensing structure, and the silicone oil is used as the temperature sensing material of the capacitive structure. A processing circuit on a printed circuit board is designed to complete the measurement. A theoretical model is constructed to describe the behavior of the relative dielectric constant and the thermal expansion coefficient over a certain range of temperatures. Preliminary experimental results show that the variation of the relative dielectric constant and the thermal expansion coefficient versus temperature could be detected real timely and simply based on this method.