High sidelobe rejection and miniature SAW filters using unidirectional and cascaded structures

A new type of SAW devices has been proposed which compose a group type unidirectional technique and cascaded interdigital transducers (IDTs) structure to achieve desired performances without the gratings and the external phase shifters. In order to confirm the prediction, simulations and experiments are applied. We select the equivalent circuit model and circuit composition procedure as a simulation technique. The predictions are verified by the simulations and the experiments. The structure is applied to a Ring-type filter which is mounted in 3 mm square package. The high sidelobe rejection and miniature performances of the filer are found.