Longitudinal-mode leaky SAW resonator filters on 64° Y-Xlithium niobate

摘要

Y-parameter modeling is applied to obtain the frequency responsenof a first/third dual-mode longitudinally-coupled leaky-SAW (LSAW)nresonator-filter on 64°C Y-X LiNbO3. Conventionalndriving-point and transfer admittance relationships for SAW filters arenmodified to incorporate the effects of LSAW reflection and bulk-wavenscattering in the interdigital transducers and are expanded to includenreflection gratings with shorted-metal strips. As inferred fromnexperiment, the grating parameters incorporate a phase-shift term tonrelate the anomalous dispersion of shorted gratings, as well as anmodified phase-slope parameter between input and output interdigitalntransducers (IDT's). Good agreement is obtained with experimentalnresults published for 836.5 MHz two- and four-pole structures in thenmaximum-bandwidth configuration