Abstract This paper describes a useful design technique to achieve a nonlinear phase SAW filter using slanted finger interdigital transducers (SFITs) or tapered interdigital transducers which are suitable for wide-band filters in intermediate frequency stages. A required nonlinear phase response in the passband can be obtained by changing center-to-center distances between input and output SFITs along an axis perpendicular to the SAW propagation axis. The design is based on a building-block approach in the frequency domain. A nonlinear phase SAW filter with a center frequency of 70~MHz and a fractional bandwidth of about 10\% is demonstrated on x-cut 112.2&#deg; y-propagating LiTaO3. Because the substrate has a power flow angle of 1.55 degrees, the SFIT pattern is tilted along that angle. Good agreement between theoretical and experimental results is obtained.
1998 IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 45:41-47
© 1998, by The Institute of Electrical and Electronics Engineers, Inc. All rights reserved.