Branching filter and communication device
US7106148B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 25, 2005 |
| Grant date | Sep 12, 2006 |
| Priority date | — |
| Expiry date | Apr 4, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H9/568
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A branching filter includes an antenna terminal, a transmission-side filter and a reception-side filter which are connected in parallel to the antenna terminal, and a matching circuit positioned between the antenna terminal and the reception-side filter. The reception-side filter is a ladder-type filter in which the frequency of a series resonator is higher than the antiresonant frequency of a parallel resonator. The transmission-side filter is a ladder-type filter and is the capacitance in the passband of the reception-side filter, and, because of the capacitance, the inductance of the impedance of the reception-side filter, when seen from the antenna terminal side, is reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.