Saw device with apodized IDT

摘要

A SAW (surface acoustic wave) device includes a substrate having thereon at least one apodized IDT (inter-digital transducer). The axis of the apodization pattern is inclined towards a driven conductive rail of the IDT at the ends of the pattern, whereby the driven end fingers have a low capacitive coupling to a ground plane on which the substrate is supported. The capacitive coupling to the ground plane may also be reduced by supporting the substrate on the ground plane via an insulating support, whereby an air gap or the insulating support decreases the capacitance between the IDT and the ground plane.