Fabrication of a Flexible Film Bulk Acoustic Resonator for Wireless Sensor Networks

The exceptional properties of film bulk acoustic resonators (FBARs) such as low power consumption, high quality factors and high working frequencies make them the gold standard for radio frequency resonators. Once in the acoustic domain, the travelling waves frequencies become susceptible to the conditions of the propagating medium. In this context, their fabrication on flexible and wearable substrates represents a strategical step forward to obtain a new generation of highly sensitive sensors. In this work, we propose the fabrication and the characterization of an Aluminium Nitride-based FBAR directly fabricated on a flexible polymeric substrate. The fabrication process results very effective as the resonator shows a clear resonance around 1.56 GHz, a 3dB quality factor of 157 and can be integrated with antennas to accomplish a wireless sensor node.