Optimization on Thin Film Bulk Acoustic Resonator (FBAR) by Transmitting Line Method

Abstract:

In this paper, the transmitting line method is applied to analyze the properties of FBAR, and the input impedance equation is obtained, and the series resonance frequency f_s and the parallel resonance frequency f_p are calculated by this method. Moreover, the elastic effects of the electrode on the effective electromechanical coupling factor, k²_eff , and the resonance factor, Q_{s> , of FBAR are investigated by the transmitting line method. Results indicate that the acoustic impedance ratio of the electrode to the piezo-film dominantly determines the behaviors of the k²eff} , the variation of Q_s versus the thickness of the electrode crucially depends on the acoustic impedance ratio of electrode to piezoelectric films. The results will be applied in the theoretical optimization of FBAR, which are available to optimize the fabrications of FBARs and similar devices.

• Periodical: Advanced Materials Research (Volume 569)
• Pages: 149-152
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.569.149
• Online since: September 2012
• Authors: Tao Zhang, Min Li, Ping Liu, Bin Sun, Sheng Nan Zhou
• Keywords: Effective Electromechanical Coupling Factor, Elastic Effects, FBAR, Transmitting Line Method

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