Design and fabrication of thick-film PZT-metallic triple beam resonators

This paper describes the design, fabrication and testing of metallic triple beam resonators in which the vibrations are driven and detected by thick-film lead zirconate titanate (PZT) elements. The resonator substrate was fabricated in 430S17 stainless steel by a simultaneous, double-sided photochemical etching technique and the thick-film piezoelectric elements were deposited by a standard screen-printing process. Finite element analysis (FEA) has been employed to simulate the modal behaviour with stress distribution of the resonator and to optimise the positioning of the thick-film PZT elements on the resonator structure. The combination of the two batch-fabrication processes, i.e. photochemical etching and screen printing, provides the opportunity for mass production of the device at low cost. The resonator, a dynamically balanced triple beam tuning fork (TBTF) structure 15.5–23.5 mm long and 6.5 mm wide, has a favoured mode at between 5 and 7 kHz with a Q-factor over 3000 operating in air. This novel device should find wide applications.