A SAW (Surface Acoustic Wave) Dispersive Delay Device.
Patent Application, Filed 24 Aug 87,
DEPARTMENT OF THE ARMY WASHINGTON DC
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A SAW dispersive delay device comprises a high-coupling piezoelectric substrate such as lithium niobate, and input and an output metallic transducer deposited on the piezoelectric substrate, and a pair of coextensive metallic reflective arrays deposited on the same substrate and respectively aligned with the transducers. The arrays comprise a number of shorted and open reflectors which are alternately interleaved. The reflectors are inclined substantially 45 deg with respect to the aligned transducer propagation direction. The periodicity of the reflectors varies along the length of each reflective array so that different frequencies are reflected at different locations along each array to thereby provide a different delay path. The periodicity variation is the same in the two arrays. The periodicity of these reflectors varies in a manner consistent with a prescribed dispersion characteristic.