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US 4,060,777 AGranted
Guided elastic surface wave filter
AssigneePiezo Technology Inc.
InventorsHarry Frank Tiersten, Robert Chastain Smythe
Life of this patent
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Abstract
A resonator and resonator type wave filter formed by a piezoelectric body on which acoustic surface waves are guided and reflected and in which mode coupling in a direction transverse to the surface wave propagation is utilized. The transverse modes are controlled so as to provide improved response characteristics by minimizing suppressing and/or otherwise controlling unwanted modes of vibration in the body.
Claims25
A surface wave resonator device comprising:
- substrate means having at least a surface layer of piezoelectric material,
- acoustic surface wave transducer means disposed on said piezoelectric surface of said substrate means operable in response to an input electrical signal to produce propagation of acoustic surface waves on said piezoelectric surface of said substrate means in a first direction,
- means forming first and second arrays of elements on the piezoelectric surface of said substrate means on opposite sides of said acoustic surface wave transducer means and being multiply reflective to the acoustic surface waves propagated by the transducer means to produce by energy trapping at least one region on the piezoelectric surface of said substrate means wherein a first acoustic standing wave resonance occurs which is generally in said first direction and a second acoustic standing wave resonance occurs in a second direction which is generally transverse to said first direction, and
- means for controlling at least one characteristic of the second acoustic standing wave.
1 more element
Dependencies are inferred from the claim text.