EFFECT OF TAPERING ON SAW GROOVED REFLECTOR ARRAYS.

The effect of tapering on the performance of SAW grooved reflector arrays has been an important unknown both theoretically and experimentally. It has generally been conjectured that by tapering grooves at the start of an array so that the discontinuity encountered by an incident SAW is blunted the loss of power through bulk-wave generation would be reduced. This work represents the first theoretical treatment of tapered SAW grooved reflector arrays which finds the foregoing conjecture about tapered SAW grooved arrays to be incorrect. Using a linear taper and an array comprised of a tapered region followed by a uniform array, it is found that, for a fixed total number of grooves, as the tapered region is increased the SAW reflectivity of the array decreases and the transmission loss through the array increases but the bulk-wave loss remains essentially constant.