Design a new MEMS tunable capacitors using electro-thermal actuators

This paper presents a new structure for the Micro-electromechanical capacitors with high capacitance and tuning range. The obvious feature of the proposed capacitor is the use of a thermal actuator to change the dielectric coefficient of capacitor. In this work, BaTiO3 is used as a dielectric. Due to its high dielectric coefficient, BaTiO3 increases the capacitance in this structure. Another characteristic of this material is that it changes the dielectric coefficient linearly in a specified temperature range. Through this work, given the thermal properties of the dielectric, a variable capacitor with a wide tuning range is made using a heater as a thermal actuator. The proposed variable capacitor has a one-piece structure and removes problems such as the pull-in effects completely by eliminating the moving parts. The results show that the tuning range of the proposed capacitor is about 600 % and its capacitance density is equal to 41.66 mu F cm(-2). This capacitor can be used in the MEMS telecommunication systems, particularly radars that require high capacity with too small sizes.