ARRANGEMENT WITH TWO PIEZOELECTRIC LAYERS, AND METHOD OF OPERATING A FILTER DEVICE

摘要

The invention relates to an arrangement with two piezoelectric layers (2, 5) and to a method of operating the arrangement as a filter. One (2) of the two piezoelectric layers (2, 5) in the arrangement is situated between an electrode (3) and a middle electrode (4), and the other one (5) of the two piezoelectric layers (2, 5) is positioned between another electrode (6) and said middle electrode (4) such that a bulk acoustic wave resonator is formed. The one and the other electrode (3, 6) and the middle electrode (4) are connected to circuitry means for applying high-frequency signals to at least one of the two piezoelectric layers (2, 5) such that the bulk acoustic wave resonator has at least one resonance frequency when the circuitry means are in one switching state, and that the bulk acoustic wave resonator has at least one other resonance frequency different from the at least one resonance frequency when the circuitry means are in another switching state.