Design of SAW filters on langasite

Abstract

Due to good temperature stability and moderately high electromechanical coupling coefficient langasite (Li3Ga5SiO4 or LGS) is known as a promising material for SAW devices. The characteristics of the Rayleigh wave propagation on LGS have been studied fairly well. However, no design of SAW devices on LGS suitable for modern communication systems has been reported as yet. In this paper, transversal filters on LGS based on bidirectional interdigital transducers, and low-loss filters on LGS based on natural single phase unidirectional transducers (NSPUDT), are described. The filters on LGS have exhibited better electrical parameters than their analogues on quartz and lithium tantalate.