1984 年 40 巻 12 号 p. 814-821
This paper proposes saddle-like bending vibrators of a single square-plate of piezoelectric ceramics, in which interdigital electrodes are formed on the plate face and used for both poling treatment and excitation of vibration. There are two saddle-like bending vibrators, anti-symmetric and symmetric modes. For excitation of anti-symmetric or symmetric mode, interdigital electrodes are set in parallel to a diagonal or a side line of the plate, respectively. Both of piezoelectric transverse and longitudinal couplings, k_<31> and k_<33> contribute to excitation of the vibration. These bending vibrators have several merits of no bonding layer, easy mechanical support, very small spurios responses and relative small capacitance ratio. The resonance frequencies and distributions of vibrational displacement and strain are calculated for anti-symmetric and symmetric modes by using the finite element method. The caluclations also clarify the electrode-configuration dependence of the capacitance ratio and spurious responses of vibrator, and give the condition of electrode configuration for suppression of spurious responses. These are confirmed experimentally.