Design and analysis of single phase unidirectional transducers

Single-phase unidirectional transducers for SAW low-loss filters find increasing application in telecommunication systems like mobile telephone and cordless phone. These transducers employ a single metal layer fabrication which is important for low-cost and high-volume production. The matching of the filter is in general done with a simple two-element matching network on the input and the output of the filter. The design of the transducers employing withdrawal weighting and apodization is described. An extensive analysis of the transducer P-matrix elements including second-order effects like diffraction and finger resistance is presented. The measured filter performance is shown and compared to the analysis results