Parametric study of laterally acoustically coupled bulk acoustic wave filters

Johanna Meltaus, Tuomas Pensala, K. Kokkonen

    Research output: Contribution to journalArticleScientificpeer-review

    16 Citations (Scopus)

    Abstract

    Acoustically coupled thin-film bulk acoustic wave resonator filters, in which the coupling takes place mechanically in the lateral direction between closely-spaced narrow resonators, are a promising approach to passband filtering at gigahertz frequencies. In this paper, filters with interdigital electrode structures are studied. Electrode number, electrode width, and coupling gap width are varied. The resonators are solidly mounted, having an acoustic mirror isolating the resonator from a Si substrate and providing the means to engineer the acoustic dispersion properties of the resonators. The center frequency of the filters is around 2 GHz. Electrical frequency responses of the filters are measured and the strength of the lateral acoustic coupling is calculated from the measurements. The effects of device parameters on the acoustic coupling and the obtainable filter bandwidth are analyzed in detail. A bandpass filter with 4.9% bandwidth, minimum insertion loss of 2 dB and sharp transition from passband to suppression band, is presented.
    Original languageEnglish
    Pages (from-to)2742-2751
    Number of pages9
    JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
    Volume59
    Issue number12
    DOIs
    Publication statusPublished - 2012
    MoE publication typeA1 Journal article-refereed

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