Jiro Inoue

Strip-Type Resonators Using Second-Harmonic Thickness-Extensional Vibration

The strip-type resonator that uses 2nd-harmonic thickness-extensional (TE2-mode) vibration in a two-layered monolithic piezoelectric plate was developed for a ceramic oscillator. By using the TE2-mode vibration, piezoelectric ceramic materials that have better temperature characteristics and higher Qm could be utilized. Furthermore, TE2-mode vibration has no problems such as spurious responses often found in the 3rd-harmonic thickness extensional (TE3-mode) vibration in a single-layered piezoelectric plate. By shaping the resonator into a strip, the resonator was miniaturized. By means of the finite element method, the displacement distribution and the relationship between resonator width and spurious responses were analyzed. From the results, it was clarified that the resonator could be miniaturized and had good frequency characteristics. Those superior characteristics were demonstrated in an experiment. It was recognized that there was no spurious response that disturbed stable oscillation and that the volume of the resonator was less than 1/10 of that of conventional trapped-energy resonators using the TE3-mode vibration in a single-layered piezoelectric plate.

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.

Resonant properties of ceramic resonators coated with plasma polymerized styrene film

Ceramic resonators (CR) utilize the mechanical resonance of piezoelectric ceramics, typically of lead zirconate titanate (PZT), which provide various vibration modes depending on the resonance frequency (Jaffe, B. et al., 1971; Murata Manufacturing Co., Ltd., www.murata.com/calalog/p19e7.pdf, 2001). Recently, quartz crystal microbalance (QCM) techniques have found wide application in chemical and biosensors (Lu, C. and Czanderna, A.W., 1984). The high-frequency QCM shows high mass sensitivity, but it has a narrow working range for mass loading. The CR is expected to show a property similar to that of QCM, even though the mass loading effect on CR has not been investigated. The resonant properties of a CR coated with a plasma polymerized styrene film (PPSF) to give a mass loading effect were examined and compared with those of a QCM device.

Supporting method of resonators using the dynamic damper

The paper describes a supporting method of resonators using the dynamic damper, and its effectiveness is analyzed by means of the finite-element method analysis and experiments. The supporting structure of a resonator wherein the cross bar is provided at the vibration-transmitting part is proposed. It is ascertained that when the ratio of resonant frequency of the resonator to that of the cross bar is set to be approximately 1, the cross bar functions as the dynamic damper to suppress the transmitted vibration. In the experimental device the resonator having the dynamic damper shows good frequency characteristics when it is secured to the outer substrate.

PIEZOELECTRIC CERAMIC RESONATOR USING THE FORK-MODE VIBRATION

A compact and easily packaged piezoelectric ceramic resonator in the kHz medium band using the fork-mode vibration has been studied. The fork-mode vibration was examined by making a slit in rectangular ceramics. Displacement and charge distribution were analyzed by the finite element method, and optimum electrode configuration was estimated. An ultra thin 200 kHz resonator was fabricated and evaluated.