Band reject filters
US7777597B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2005 |
| Grant date | Aug 17, 2010 |
| Priority date | — |
| Expiry date | Jul 15, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/74
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Band reject filters are disclosed. A band reject filter includes a first acoustic resonator and a second acoustic resonator, each of which has either shunt resonators adapted to resonate substantially at respective resonance frequencies defining a rejection frequency band or series resonators adapted to anti-resonate substantially at respective anti-resonance frequencies defining the rejection frequency band. These resonators are connected through a phase shifter which imparts an impedance phase shift of approximately 45° to 135°. Exemplary applications of the band reject filters disclosed herein include implementation as an inter-stage band reject filter for a base station power amplifier for a wireless communication system, as a radio frequency band reject filter in a duplexer for a wireless communication terminal, and in a low noise amplifier input stage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.