Anomalous asymmetric acoustic radiation in low-loss SAW filters

The experimental discovery of a novel acoustic loss mechanism in SAW filter s at RF frequencies is reported. The phenomenon is characterised by an unex pected spatial distribution of the surface-acoustic wave field. The observa tion and measurements were performed with a specially constructed scanning laser-interferometric probe. Current simulation methods and known phenomeno logical models applied to SAW resonators have no predictive ability to desc ribe the discovered effect.