Surface acoustic wave filter with attenuation poles
AssigneeOki Electric Industry Co., Ltd.
InventorsKazushige Noguchi, Satoshi Terada, Wataru Ohashi, Tomokazu Komazaki
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Abstract
A high-performance SAW filter is to be provided which has lower insertion loss in a pass band and high attenuation in an attenuation band on the low frequency side of the pass band. In a SAW filter with attenuation poles configured of a two-port circuit for filtering for forming a ladder type SAW filter using a SAW resonator and a two-port circuit for impedance formed of an impedance serially connected, the impedance of the two-port circuit for impedance is configured so as to form an attenuation band of a predetermined width having a sufficient attenuation characteristic on the low frequency side of a pass band.
Claims9
A surface acoustic wave filter with attenuation poles comprising:
- a two-port circuit for filtering for forming a ladder type surface acoustic wave filter with a surface acoustic wave resonator;
- and
- a two-port circuit for impedance formed of an impedance serially connected,
- wherein the impedance of the two-port circuit for impedance is configured so as to form an attenuation band of a predetermined width having a sufficient attenuation characteristic on a low frequency side of a pass band.
A surface acoustic wave filter with attenuation poles comprising:
- a two-port circuit for filtering for forming a ladder type surface acoustic wave filter with a surface acoustic wave resonator;
- and
- a two-port circuit for impedance formed of an impedance serially connected,
- wherein the two-port circuit for impedance is configured of a π type circuit formed of three impedances so as to form an attenuation band of a predetermined width having a sufficient attenuation characteristic on a low frequency side of a pass band.
Dependencies are inferred from the claim text.