A new type SPUDT SAW for use in high frequency around 2 GHz

This paper introduces a new type of SPUDT structure, which enables the design of SAW filters or delay-lines up into the 2 GHz range. The structure consists of two groups of spatially harmonic transducers e.g. Se=5 (+ + - + -) or Se=8 (+ + - + - - + -) and one group of reflectors positioned between the two groups of harmonic transducers. In the paper, the general operating principle of the new SPUDT is discussed. To confirm this new technique, a slanted type SAW filter using the new SPUDT structure with central frequency of 2.14 GHz was designed and fabricated. The directionality of this new SPUDT structure has been demonstrated by measurement.