Surface acoustic wave resonator, surface acoustic wave oscillator, and surface acoustic wave module unit
AssigneeSeiko Epson Corporation
InventorKunihito Yamanaka
Life of this patent
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Abstract
It is possible to reduce the size of a surface acoustic wave resonator by enhancing the Q value. In a surface acoustic wave resonator in which an IDT having electrode fingers for exciting surface acoustic waves is formed on a crystal substrate, a line occupying ratio is defined as a value obtained by dividing the width of one electrode finger by the distance between the center lines of the gaps between one electrode finger and the electrode fingers adjacent to both sides thereof, and the IDT includes a region formed by gradually changing the line occupying ratio from the center to both edges so that the frequency gradually becomes lower from the center to both edges than the frequency at the center of the IDT.
Claims14
A surface acoustic wave resonator comprising:
- a piezoelectric substrate;
- and
- an interdigitated transducer including electrode fingers for exciting surface acoustic waves disposed on the piezoelectric substrate,
- wherein a line occupying ratio is defined as a value obtained by dividing a width of one of the electrode fingers by a distance between a center line of a gap between the one electrode finger and an adjacent one of the electrode fingers and a center line of a gap between the one electrode finger and the adjacent one of the electrode fingers to the other side thereof, and
- wherein the interdigitated transducer includes a region formed by sequentially changing the line occupying ratio from a center to both edges thereof so that the frequency gradually becomes lower from the center to both edges than the frequency at the center of the interdigitated transducer.
Dependencies are inferred from the claim text.