Suppressing parasitic sidebands in lateral bulk acoustic wave resonators

Tapani Makkonen (Inventor), Tuomas Pensala (Inventor), Markku Ylilammi (Inventor)

    Research output: PatentPatent


    Acoustic wave filter devices are disclosed. In an embodiment, the device includes an acoustic wave resonator and a reflecting layer located below the acoustic wave resonator. The wave resonator includes an input electrode including a first electrode and a counter electrode, a piezoelectric layer sandwiched between the first electrode and the counter electrode, and an output electrode. The piezoelectric layer has a first region covered by the first or the output electrode, and a second region not covered by any of the first and the output electrode. The first region has a second order acoustic thickness-shear resonance (TS2) mode dispersion curve with a first minimum frequency, and the second region has a TS2 mode dispersion curve with a second minimum frequency. The reflecting layer's thickness is such that a difference between the first minimum frequency and the second minimum frequency is less than 2% of a filter center frequency.

    Patent family as of 27.1.2022
    US11223341 BB 20220111 US20190660480 20191022      
    US2021119600 AA 20210422 US20190660480 20191022      
    WO21078916 A2 20210429 WO2020EP79840 20201022      
    WO21078916 A3 20210722 WO2020EP79840 20201022

    Link to currentpatent family on right 

    Original languageEnglish
    Patent numberUS2021119600
    IPCH03H 9/ 54 A I
    Priority date22/10/19
    Publication statusPublished - 22 Apr 2021
    MoE publication typeH1 Granted patent


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