Toshihiko Unami

Multilayer Ceramic Resonators Using a Flexural Vibration Mode and their Application to Filters

Multilayer ceramic resonators using a piezoelectric longitudinal-effect flexural vibration mode have been developed. The resonators are able to be designed in a much smaller format while maintaining high performance than the multilayer longitudinal resonators which we previously presented. Utilizing internal divided electrodes and floating electrodes makes it possible to generate a flexural vibration mode without complicating the process of connecting electrodes or polarizing. The relationship between the ratio of piezoelectric area in the length direction and the bandwidth, and the effects of the gap and distance from the internal electrodes on the resonator characteristics, are analyzed by the finite element method. Resonators and ladder filters are investigated and their superior characteristics and small size have been demonstrated.

Multilayer Ceramic Resonators using the Piezoelectrically Stiffened Length Mode Vibration

Multilayer ceramic resonators that utilize the piezoelectrically stiffened length mode vibration and have a much smaller size than any other vibration mode resonators, are developed. Characteristics related to the internal and external electrodes such as bandwidth and capacitance, are analyzed by the finite element method. According to the results, resonators and ladder filters are investigated and their superior characteristics are demonstrated.