Abstract

We report a high-quality-factor (Q) film bulk acoustic resonator (FBAR) operating in liquid environments. By integrating a microfluidic channel to a longitudinal-mode FBAR, a Q of up to 150 is achieved with direct liquid contacting. A transmission line model is used to theoretically predict the Q behavior of the FBAR. The model suggests an oscillatory pattern of Q as a function of the channel thickness and the acoustic wavelength in the liquid, which is experimentally verified by precisely controlling the channel thickness. This FBAR biosensor is characterized in liquids for the real-time in situ monitoring of the competitive adsorption/exchange of proteins, the Vroman effect. The FBAR offers a minimum detectable mass of 1.35 ng2 and is successfully implemented in a Pierce oscillator as a portable sensing module.

Original languageEnglish (US)
Article number5668490
Pages (from-to)213-220
Number of pages8
JournalJournal of Microelectromechanical Systems
Volume20
Issue number1
DOIs
StatePublished - Feb 1 2011

Keywords

  • Acoustic resonators
  • Q factor
  • biomedical transducers
  • piezoelectric resonators

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering

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