Title :
Automatic computer-aided design of SAW filters using slanted finger interdigital transducers
Author :
Yatsuda, Hiromi ; Yamanouchi, Kazuhiko
Author_Institution :
Japan Radio Co. Ltd., Saitama, Japan
Abstract :
This paper describes a design procedure for surface acoustic wave (SAW) filters using slanted finger interdigital transducers (SFIT) that are suitable for mid-band or wideband applications. The SFITs cannot represent the impulse response directly, in contrast to apodized IDTs. A design method for SFITs based on a building-block approach in the frequency domain is described. An automatic computer-aided design tool for SFIT filters has been achieved. The SFIT filters can be designed using a withdrawal weighting for stop-band responses, an aperture weighting for pass-band amplitude responses, and a distance weighting for pass-band phase responses. In addition, a SFIT pattern for photo mask can be automatically designed using this tool. Using this tool, an SFIT filter with a relative bandwidth of 15% was designed on an x-cut 112y-direction LiTaO/sub 3/ substrate.
Keywords :
CAD; band-pass filters; frequency-domain analysis; interdigital transducers; lithium compounds; masks; surface acoustic wave filters; surface acoustic wave transducers; ultrasonic transducers; LiTaO/sub 3/; LiTaO/sub 3/ substrate; SAW filters; SFIT filters; aperture weighting; automatic computer-aided design; automatic computer-aided design tool; building-block approach; design procedure; distance weighting; frequency domain; mid-band applications; pass-band amplitude response; pass-band phase response; photo mask; slanted finger interdigital transducers; stop-band response; surface acoustic wave; wideband applications; withdrawal weighting; Acoustic transducers; Acoustic waves; Application software; Band pass filters; Design automation; Design methodology; Fingers; SAW filters; Surface acoustic waves; Wideband;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
