S.A.W. device reflectors weighted by combination of withdrawn and segmented lines

A technique for weighting surface acoustic wave (s.a.w.) device reflectors which combines withdrawal weighting and segmented lines is described. This scheme has the advantage of lower photolithographic mask costs through the partial use of withdrawal weighting, and the advantage of closely approximating the desired weighting function by partial use of segmented (dotted) lines. Effectiveness of this combined weighting technique is demonstrated by its use in sidelobe suppression in two-port SAW resonators; however, combined-type weighted reflectors can be used to advantage in all types of filters utilising reflective arrays.