Design methodology and experimental results for new ladder-type SAW resonator coupled filters

摘要

Design methodology and experimental results for a new type of SAW filter called an "extended SAW resonator coupled filter" used in 800 MHz and 0.6 to 1.0 watt cellular radios are presented. The new filters have very small nonlinearities as well as high-performance and high-power characteristics. We have proposed a new equivalent circuit model for IDTs with leaky SAWs, which includes the propagation losses due to leakage and conductances caused by bulkwave radiation. Synthesis procedures for the new SAW filters based on the new treatments of leaky SAWs are discussed, and simulation and experimental results are also given. The new filters satisfy not only the required frequency-response specifications but also the spurious response sensitivity for an antenna duplexer used in USA cellular radio.