Longitudinally coupled leaky surface acoustic wave resonator filter

摘要

A longitudinally coupled leaky surface acoustic wave (LSAW) resonator filter has a wide bandwidth, low insertion loss and return loss characteristics, and high power handling capability. The LSAW resonator filter includes a plurality of longitudinally coupled LSAW resonator tracks disposed upon a piezoelectric substrate and connected in series. The resonator tracks each include reflective gratings and interdigital transducers (IDTs) disposed end-to-end. Acoustic resonant cavities are formed between each IDT and its neighboring IDTs or gratings by chirping the fingers of the IDT in the vicinity of the cavities. Phase discontinuity is eliminated; reflective bulk acoustic wave scattering is reduced; and improved insertion loss and power handling capability are achieved.