Automatic computer-aided design of slanted finger SAW filters using a building-block method

This paper describes a design procedure for surface acoustic wave (SAW) filters using slanted finger interdigital transducers (SFITs) which are suitable for mid-band or wide-band applications. The SFITs cannot represent the impulse response directly, in contrast of 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.