Retractable helical antenna
US4725845A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 3, 1986 |
| Grant date | Feb 16, 1988 |
| Priority date | — |
| Expiry date | Mar 3, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q9/145
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A retractable antenna assembly is disclosed for tuning an antenna having a helical section to frequency by selectively positioning an appropriate tuning core within the helix. The antenna frequency can either be raised or lowered through the use of conductive or permeable tuning core compositions. The core positioning mechanism is implemented by affixing the tuning core to a portion of the antenna supporting rod slideably located within the helix. This helical antenna/tuning core configuration is readily adaptable to miniature portable radios by providing a helical antenna assembly which is retractable within the radio housing in the receive-only or standby mode, and which is outwardly extendible from the radio housing for use in the active transmit/receive mode. A unique barrel-cam latching mechanism is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.