Highly flexible piezoelectric MEMS resonators encapsulated in polymer thin films

This paper presents a flexible film bulk acoustic resonator (FBAR) with superior mechanical flexibility and electrical performance. The quality factor (Q) and effective coupling coefficient (k_t²_eff) of the flexible FBAR are 1108 and 5.0%, respectively. The resonator can be bent to a minimal radius of 0.5 mm with little electrical performance degradation. Additionally, the resonator remains high performance after 100 bending cycles. We believe that the device can be used in applications that require both flexibility and functionality, for example, wearable communication and drug delivery. Moreover, the solution proposed in this paper provides a viable approach to the fabrication of a variety of flexible MEMS devices.