SCATTERING ANALYSIS AND DESIGN OF SAW RESONATOR FILTERS

Surface acoustic wave (SAW) resonator passband filters are analyzed through a scattering formalism of considerable power. A broad class of multiple-resonator filters is described in terms of basic building blocks, including bidirectional and unidirectional transducers, reflection gratings, and a variety of interresonator coupling arrangements. The description of each block is developed from abstract scattering parameters to a concrete design based on a model, in most cases. Computed filter and coupler transfer characteristics illustrate some of the trade-offs available in two-resonator filters designed with different building blocks. Off-resonance rejection levels are characterized and compared; the results are applicable to multiple-resonator filters. Design procedures are derived for filters realized with resonators of finite unloaded Q. Detailed design relations and curves are presented for one- and two-resonator filters. The design of higher order filters is made possible through a translation of filter synthesis tables in terms of SAW parameters. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.