Composite lateral electric field excited piezoelectric resonator

• Published in: Ultrasonics Vol. 73; pp. 125 - 129
• Main Authors: Zaitsev, B.D., Shikhabudinov, A.M., Borodina, I.A., Teplykh, A.A., Kuznetsova, I.E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-01-2017
• Subjects: A holder of electrodes; Composite piezoelectric resonator with lateral electric field; Parallel resonance; Resounding piezoelectric plate; Series resonance; Parallel resonance; Resounding piezoelectric plate; Composite piezoelectric resonator with lateral electric field; A holder of electrodes; Series resonance
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2016.08.022

•Novel design of lateral electric field excited piezoelectric resonator is offered.•New method of suppression of parasitic oscillations in such resonators is invented.•Separation of electrodes holder and piezoelectric plate suppresses parasitic modes.•For composite resonator Q-factor for series/parallel resonances is equal to 15,000.•Composite resonator is easy-to-development of liquid sensor without radiation loss.
The novel method of suppression of parasitic oscillations in lateral electric field excited piezoelectric resonator is suggested. Traditionally such resonator represents the piezoelectric plate with two electrodes on one side of the plate. The crystallographic orientation of the plate is selected so that the tangential components of electric field excite bulk acoustic wave with given polarization travelling along the normal to the plate sides. However at that the normal components of field excite the parasitic Lamb waves and bulk waves of other polarization which deteriorate the resonant properties of the resonator. In this work we suggest to separate the source of the HF electric field and resounded piezoelectric plate by air gap. In this case the tangential components of the field in piezoelectric plate do not practically weaken but normal components significantly decrease. This method is realized on the composite resonator having the structure “glass plate with rectangular electrodes – air gap – plate of 128 Y-X lithium niobate.” It has been shown that there exist the optimal value of the width gap which ensure the good quality of series and parallel resonances in frequency range 3–4MHz with record values of Q-factor of ∼15,000 in both cases.