Scattering and transmission matrix analysis of SAW resonator filters with long-pair IDTs and triple composite longitudinal modes on quartz

This paper describes a technique for modeling the frequency response of a triple composite mode SAW resonator-filter on ST-quartz, with insertion loss less than 3 dB and fractional bandwidth >0.1 %. These temperature-stable filters with long-pair IDTs and thick-film metallization can find application in the UHF intermediate-frequency stages of mobile communications equipment such as the Personal Handy Phone. Scattering and transmission matrices are used here, in conjunction with a radiation conduction function, as distorted by the effects of IDT finger reflections