Thin Film Bulk Acoustic Wave Resonators for their Application in Microwave Filters

Thin film bulk acoustic wave resonator (FBAR) devices have been fabricated using ZnO films grown by RF magnetron sputtering. The FBARs have been characterized by measuring their microwave frequency performance from 2-5 GHz, It was found that the fundamental resonance frequency was 2.367 GHz. The values for the insertion loss (S
₂₁
), quality factor (Qs) and the effective electromechanical coupling coefficient (k
_eff

²
) are: 2.198 dB, 20 and 1.15%, respectively. A circuit model based on the Butterworth Van-Dyke model was used to model the FBAR and the energy losses in this device.