P6G-1 Building Block Concept in Quasi-Slanted SPUDT Synthesis Method

A modified quasi-slanted unidirectional transducer synthesis technique is suggested for design of low-loss SAW filters. This technique is aimed for optimization of long single-phase unidirectional transducers (SPUDT) with large number of electrodes that are needed for realization of either narrowband SAW filters or filters with high shape-factor of frequency responses. Electrode blocks of several wavelengths long are used as elementary units in SPUDT mounting. Each block is a carefully selected electrode structure and has specific reflection and transmission features. An assortment of usable blocks depends on substrate material and transducer type. The "scanning window" technique is used here for optimization of elementary units combination to reach the best filter selectivity.