Automatic computer-aided design of SAW filters using slanted finger interdigital transducers.
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(3) substrate.
Yatsuda
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H
Japan Radio Co., Ltd., 2-1-4 Fukuoka, Kamifukuoka, Saitama, 356-0011 Japan. yatsuda@lab.jrc.co.jp
Yamanouchi
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K