Capacitive coupled extendable antenna
US5661496A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1995 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Apr 25, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q1/244
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An capacitive coupled extendable antenna for cordless telephones and for portable cellular telephones is disclosed. The antenna is operated, in its extended state, as the equivalent of a half-wave dipole antenna due to capacity capacitive coupling between the quarter-wave helical antenna element and the quarter-wave whip antenna element and compensates, in its retracted state, the deficient capacity component of the helical antenna element owing to capacity capacitive coupling between the metal sleeve and the helical antenna element. The antenna also improves the efficiency of the whip antenna element as well as the efficiency of the helical antenna element by coupling the metal sleeve to a tube under the condition that the whip antenna element is fully inserted into the tube.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.