To solve such a problem that the characteristics of a conventional acoustic surface wave delay line is deteriorated since proper refraction correction cannot be made due to variation in manufacture.
In this acoustic surface ware delay line, an input/output pair of interdigital transducers 1A and 2A are provided by constituting plural transducer fingers 3 and outer and inner bus bars 4A, 5A, 6A and 7A connected alternately to the plural interdigital fingers on a piezoelectric substrate, the plural fingers 3 are arranged in an tilted state by an angle θ with respect to the propagating direction of the acoustic wave and intervals between the plural interdigital fingers are varied little by little along the propagating direction of the acoustic wave, the inner bus bars 4A and 5A are shaped like steps along the direction of the angle θ and the place of the inner bus bar corresponding to a crossing part where a pair of the interdigital fingers connected alternately to the outer and inner bus bars cross with each other is set to be the unit step of the shape of the steps. The width W of the unit step is set to be W=2p and the height H of the unit step is set to be H=W.tan π. Thus, the characteristic deterioration due to refraction or reflection can be reduced.
MISU KOICHIRO
YOSHIDA KENJI
IHATA KOUJI
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