Magnetically tunable surface acoustic wave devices
AssigneeLucent Technologies Inc.
InventorsJohn Edwin Graebner, Sungho Jin, Wei Zhu
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Abstract
In accordance with the invention, the operating frequency of a SAW device is magnetically tuned. In a first embodiment, the SAW device comprises a piezoelectric layer mechanically coupled to a substrate or body of magnetostrictive material. Strains magnetically induced in the magnetostrictive substrate is coupled to the piezoelectric layer, altering the velocity at which it can transmit acoustic waves. In an alternative embodiment, surface waves are directly generated in a magnetostrictive material and the velocity is directly altered by an applied magnetic field.
Claims9
A surface acoustic wave filter tunable within the gigahertz range comprising:
- a body of piezoelectric material having a surface and a thickness transverse to said surface in the range 0.1 to 2000 micrometers;
- at least one surface wave transducer coupled to said surface;
- and
- a body of magnetostrictive material having a surface and a thickness transverse to said surface at least five times thicker than the thickness of said piezoelectric body,
- said body of piezoelectric material bonded onto said body of magnetostrictive material with said surfaces parallel, said magnetostrictive material expanding or contracting with an applied magnetic field, whereby varying an applied magnetic field tunes the operating frequency of said surface acoustic wave filter.
Dependencies are inferred from the claim text.