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Shokichiro YOSHIKAWA Hiromi YATSUDA Osamu YANO
This paper describes the wide-band linear phase surface acoustic wave (SAW) filters composed of slanted finger transducers. To calculate the characteristics of slanted finger transducers, the transducers were divided to multiple channels. In each channel, amplitude and phase performance for the slanted fingers are approximated as that of normal fingers, and admittance matrix of each channel is calculated by applying Smith's equivalent circuit, after that, all the channels are connected in parallel one another. Two filters with 13% and 50% fractional bandwidths were designed using a finger pair weighting technique. Considering the features of the filters composed of the slanted finger transducers, that their pass-band characteristics can be controlled by changing the conditions of propagation path, filters having notches in the pass-band were studied. Fixed and variable notch filters with 50% fractional bandwidth were designed, and characteristics were verified by experiments.