LONGITUDINAL SCHWINGENDES MECHANISCHES KOPPELFILTER UND VERFAHREN ZU DESSEN HERSTELLUNG

摘要

A composite longitudinal vibration mechanical filter for delivering out a supplied high-frequency signal in a predetermined frequency range includes a plurality of vibratable bodies including input and output longitudinal vibratable tuning bars with piezoelectric members superposed thereon, coupling elements by which the longitudinally vibratable tuning bars are coupled to each other, supporting elements projecting respectively from the input and output longitudinally vibratable tuning bars, and a holder to which the supporting elements are attached. At least one resonant frequency adjusting finger is disposed on at least one of the vibratable bodies. Grooves are defined in the longitudinally vibratable tuning bars at the same time that they are fabricated. The grooves extend in the direction in which the longitudinally vibratable tuning bars are longitudinally vibratable, and are shorter than the length of the longitudinally vibratable tuning bars. Through holes may instead be defined in the longitudinally vibratable tuning bars, the through holes having an opening size smaller than the wavelength of the longitudinal vibration of the longitudinally vibratable tuning bars. Piezoelectric members are fixedly superposed on the input and output longitudinally vibratable tuning bars in sandwiching relation thereto.