Acoustic Multistrip Device Techniques.
Final rept. 1 Jul 73-1 Apr 75,
HUGHES AIRCRAFT CO FULLERTON CALIF GROUND SYSTEMS GROUP
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The report describes the results of a study of acoustic multistrip coupler MSC devices and techniques. A generalized, normal mode field model was developed which successfully predicts the transfer characteristics of multistrip couplers of arbitrary geometrical and material properties. When applied to MSC components requiring fractional transfer efficiency, especially the -3db coupler, it was found that the response characteristics could be conveniently modified by varying the stripe spacings in each track of the coupler. Specifically, fractional efficiency couplers with broad, symmetrical passbands were predicted and demonstrated experimentally. A technique for minimizing radiation losses in the interconnection regions of MSC components by machining a cavity in the piezoelectric substrate under the interconnection region and replacing it with a nonpiezoelectric filler was also investigated, but it was unsuccessful primarily due to the nonuniformity of filler and substrate material thermal expansion coefficients.
- Line, Surface and Bulk Acoustic Wave Devices