The property of temperature-frequency drift has an effect on the passband ripples, center frequency and insertion loss of FBAR filters, reducing the reliability of its electrical application. A temperature-frequency drift simulation of a typical Mo/AlN/Mo FBAR is achieved by means of finite element analysis software ANSYS, the simulated temperature coefficient of frequency is about-35ppm/°C within the temperature range of-50°C~150°C. By adding a compensated layer with positive temperature coefficient in the FBAR structure, the effects of the compensated layer thickness on temperature-frequency drift, resonant frequency and electromechanical coupling are analyzed. The simulated temperature coefficient of frequency of designed temperature compensated FBAR, which composed of Mo/AlN/SiO2/Mo, is about 0.8ppm/°C, the property of temperature-frequency drift is effectively improved.
Features of temperature coefficient of frequency saw longitudinally-coupled resonator filters based on lithium tantalate YXL/42
