MULTIPARAMETER TUNING OF SURFACE-ACOUSTIC-WAVE FILTERS

An experimental methodology for tuning the frequency response of surface-acoustic-wave (SAW) filters after initial fabrication is demonstrated. The filter sensitivity to perturbations in length of individual electrodes of the interdigital transducer is determined from highly accurate swept frequency measurements. Sensitivity measurements from several electrodes are then used to synthesize improved filter responses. Sensitivity measurements, measurement accuracy and control of frequency response sidelobes are demonstrated for devices fabricated on ( YZ ) lithium niobate. The tuning method provides predictions of improvement that closely match actual performance. © 1990 IEEE