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

A new type of SAW device has been proposed which composes a group type unidirectional technique and cascaded interdigital transducer (IDT) structure to achieve the desired performance without gratings and external phase shifters. In order to confirm the prediction, simulations and experiments are carried out. 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 a 3 mm square package. The high sidelobe rejection and miniature performance of the filter are evaluated