Band reject filters
AssigneeNortel Networks Limited
InventorsSteve A Beaudin, Somsack Sychaleun, Chun-Yun Jian
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Abstract
Acoustic resonators such as surface acoustic wave (SAW) devices and thin film bulk acoustic resonators (FBAR) can be configured to produce a band reject filter. Such a filter overcomes the insertion loss and power handling limitations of conventional band pass configurations and as such can be used in power amplifier and duplexer applications.
Claims19
A radio frequency band reject filter comprising a shunt acoustic resonator and a series acoustic resonator, the shunt resonator being arranged to resonate generally at the reject frequency band and the series resonator being arranged to anti-resonate generally at the reject frequency band, wherein the resonators are arranged such that there is substantially no acoustic resonance over a predetermined pass band.
A base station power amplifier for a cellular radio network, the power amplifier including at least one inter-stage band reject filter comprising a shunt acoustic resonator and a series acoustic resonator, the shunt resonator being arranged to resonate generally at the reject frequency band and the series resonator being arranged to anti-resonate generally at the reject frequency band, wherein the resonators are arranged such that there is substantially no acoustic resonance over a predetermined pass band.
A duplexer for a mobile telephone handset including an radio frequency band reject filter comprising a shunt acoustic resonator and a series acoustic resonator, the shunt resonator being arranged to resonate generally at the reject frequency band and the series resonator being arranged to anti-resonate generally at the reject frequency band, wherein the resonators are arranged such that there is substantially no acoustic resonance over a predetermined pass band.
A low noise amplifier input stage including a band reject filter comprising a shunt acoustic resonator and a series acoustic resonator, the shunt resonator being arranged to resonate generally at the reject frequency band and the series resonator being arranged to anti-resonate generally at the reject frequency band, wherein the resonators are arranged such that there is substantially no acoustic resonance over a predetermined pass band.
Dependencies are inferred from the claim text.