Synthesis algorithm of broadband withdrawal weighted SAW transducers with specified amplitude and phase responses

The proposed algorithm is intended for improvement of selectivity of the most compact surface acoustic waves (SAW) filters having one acoustic track where both an input apodized and an output withdrawal weighted (WW) interdigital transducers (IDT) are situated. Unlike the familiar methods of WW transducers optimization, our algorithm rates an IDT structure on the best satisfaction of its specifications not in the time but in the frequency domain. This approach has advantages over known methods in the case of synthesis of broadband WW transducers. Here the last algorithm modification is discussed. It can optimize WW transducers with an asymmetrical time response. This extension of algorithm possibilities allows not only to attain better transducer selectivity than in case of symmetrical WW electrode structures but to synthesize withdrawal weighted IDTs with a specified form of its phase response or of frequency dependence of group delay time