Electrically tunable and temperature compensated FBAR

This paper describes the design, fabrication and of an electrically tunable, temperature compensated film bulk acoustic resonator (FBAR) that is formed by integrating FBAR with an electrostatic MEMS actuator. About 0.9% tuning (Δf ≅26 MHz) of the series resonant frequency at 2.8 GHz has been obtained with less than 10 V. This is the highest frequency tuning reported for FBAR operating above 1GHz without any extra power consumption. Moreover, the air-gap capacitor (that forms the MEMS actuator) passively reduces the FBAR´s temperature coefficient of frequency (TCF) by about 40 ppm/°C.