Design methodology and synthesis techniques for ladder-type SAW resonator coupled filters

Abstract

New types of SAW filter called “extended SAW resonator coupled filter” have been developed for 800-MHz and 0.6 to 1.0 W cellular-radio pocket phones. They have not only high-performance and high-power characteristics but also very small 3rd-order nonlinearities. We investigated a new equivalent circuit for IDTs with leaky SAWs. This circuit includes propagation losses due to leakage and conductance caused by bulkwave radiation. Design and synthesis procedures for the new SAW filters based on new treatments of leaky SAWs are discussed. Simulation and experimental results are also given for the frequency characteristics of the filters used in an antenna duplexer of USA cellular radio