Developing a matrix of resonators with lateral electric field on piezoelectric plate

Piezoelectric resonators with lateral electric field cause a great interest of designers of multi-channel acoustic sensors. The electrodes of such resonator are deposited on one side of the plate that allows to separate resonators and analyzable objects. The main problem of the design of resonators matrix is the suppression of the unwanted oscillations, which worsen resonant properties and lead to the strong acoustic coupling between them. The method of the solution of such problem is described in the present paper. The matrix including two resonators placed on the plate of lithium niobate of X cut with thickness of 0.5 mm was experimentally investigated. The electrodes of rectangular shape with dimensions of 5×10 mm and width of gap between them of 2 mm provided the lateral electric field, which was oriented along axis Y. It has been shown that the resonance was achieved on the longitudinal acoustic wave propagating along axis X between electrodes. For suppression of unwanted oscillations the area around resonators and parts of electrodes were covered by damping layer. We measured the frequency dependencies of real and imaginary parts of electrical impedance /admittance of each resonator and determined the resonant frequency and Q-factor for series and parallel resonances. We also measured the frequency dependence of the parameter S12, which in all cases did not exceed 50 dB. It meant that resonators under study were acoustically decoupled. Thus it has been shown that damping layer provides the good quality of each resonator as well as total acoustic decoupling between them.