Two-frequency impedance matching circuit for an antenna
US5493311A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1994 |
| Grant date | Feb 20, 1996 |
| Priority date | — |
| Expiry date | Feb 28, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/38
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In order to achieve two-way communications at two different frequencies, an impedance matching circuit is coupled to an antenna. The circuit includes a first inductor which is directly coupled to the antenna. The first inductor induces antenna input impedance to be capacitive at a first resonant frequency and induces the antenna input impedance to be inductive at a second resonant frequency. The first resonant frequency is lower than the second resonant frequency. Further, a first capacitor is coupled to the first inductor. By providing the first capacitor, a reactance component at the first resonant frequency is rendered substantially equal to a reactance component at the second resonant frequency. Further, the circuit includes a second inductor and a second capacitor which are coupled between the second means and a feeder. The combination of the second inductor and the second capacitor is provided to adjust impedance, defined by the antenna and the first inductor and the first capacitor, to characteristic impedance of the feeder at the first and second resonant frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.