A simple design procedure for triple transit suppression in an apodized - Withdrawal weighted transducer filter structure

High performance SAW filters are characterized by their linear phase, low shape factor, small passband ripple, and high rejection. Classical filter design structures can achieve these performances, however the level of triple transit time spurious for these structures is typically twice the insertion loss + 6dB. The triple transit level can be reduced by adding low loss cell structures (such as Hanma-Hunsinger, EWC) to the transducers, however the filter analysis becomes inaccurate with the introduction of mechanical reflections (problems analyzing diffraction effects). The objective of this work is to develop a synthesis technique for high performance SAW filters with triple transit suppression.