Abstract: Filter chain comprising a number of monolithic units of piezoelectric material, which units vibrate according to the thickness shear mode and are provided with at least two acoustically coupled resonators and are coupled electrically one to another. The acoustic coupling between said resonators is equal for all units, whereas the electric coupling impedances between the units are substantially ohmic. Due to this the pass band of the filter is determined by the acoustic couplings and there is no need for an adjustment of the electric coupling between the units.
Type:
Grant
Filed:
April 24, 1975
Date of Patent:
September 28, 1976
Assignee:
De Statt der Nederlanden, te Dezen Vertegenwoordigd Door de Directeur-Generaal der Posterijen, Telegrafie en Telefonie