P5I-2 Lower-Loss Filters on Langasite

The advantages of langasite as a substrate material for SAW filters are not realized entirely till now because of the natural unidirectivity of most cuts available for practical applications. This paper presents new results that allow the utilization of langasite for SAW filters. The mathematic model, SPUDT cell structures and design method were developed for naturally unidirectional orientations. This approach allows designs of slanted and RSPUDT filters on yxlt/48.5726.6deg langasite with 7 dB - 10 dB insertion losses and bandwidths 1% - 3%.