Acoustic wave electromechanical device comprising a transduction region and an extended cavity

An electromechanical device comprising at least one resonator using acoustic waves propagating laterally within a piezoelectric plane resonant structure and at least comprising electrodes on one of the faces of said structure, the resonant structure comprising:

• a transduction region having a transduction length and generating acoustic waves;
• at least one free propagation region for the acoustic waves, adjacent to the said transduction region and defined in the same plane as the said transduction region;
• the total length of the resonant structure being equal to an integer number of half-wavelengths (nλ/2), the said wavelength complying with the following equation f=V/λ, with f corresponding to the resonance frequency of the said resonator and V the average velocity of propagation of the wave within the structure, so as to adjust the quality factor of the resonator fixed by the total length of the resonant structure and the coupling coefficient fixed by the ratio of the transduction length over the total length of the resonant structure;
• the resonant structure defined by the assembly of the transduction region and of the propagation region being laterally bounded by reflection regions:
• and
• wherein the piezoelectric plane structure further comprises at least one region being a tunability region formed by all or part of the propagation region and tunability electrodes formed on at least one of the faces of the tunability region so as to define at least one capacitor capable of being connected to at least one external variable impedance.