Title :
A theoretical and experimental study of low-loss SAW filters with interdigitated interdigital transducers
Author :
Smith, Peter M. ; Campbell, C.K.
Author_Institution :
Dept. of Electr. & Comput. Eng., McMaster Univ., Hamilton, Ont., Canada
Abstract :
A study of low-loss surface-acoustic-wave (SAW) interdigitated interdigital transducer (IIDT) structures is presented. A model based on mixed scattering matrices was used in the analysis. It is shown that the inherent comb frequency response of the IIDT can be smoothed by slanting the transducers in the structure. Alternatively, the combs can be enhanced to produce a compact low-loss feedback element for potential application in multimode oscillators. Experimental verification of the analysis is provided by a 3:2 slanted-finger IIDT filter with a 10% relative bandwidth of 5.9-dB insertion loss, and a comb filter with 13.4-dB insertion loss and comb spacing of about 3 MHz. The measured responses agree quite well with the theory.<>
Keywords :
surface acoustic wave filters; comb frequency response; interdigital transducers; low-loss SAW filters; mixed scattering matrices; multimode oscillators; Band pass filters; Bandwidth; Frequency response; Insertion loss; Matched filters; Passband; SAW filters; Scattering; Surface acoustic waves; Transducers;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
