Dielectrically loaded antenna and a handheld radio communication unit including such an antenna
US5945963A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 13, 1996 |
| Grant date | Aug 31, 1999 |
| Priority date | — |
| Expiry date | Jun 13, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q11/08
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A miniature antenna for operation at frequencies in excess of 200 MHz has a ceramic core in the form of a cylindrical rod having a relative dielectric constant greater than 5. Plated on the outer surfaces of the core is an antenna element structure comprising a single pair of oppositely disposed helical elements having a common central axis coincident with the central axis of the core. At a distal end of the antenna, they are connected to a coaxial feeder structure passing axially through the core, and at their proximal ends they are connected to the rim of a cylindrical trap conductor which, at the proximal end of the core is coupled to the screen of the feeder structure. At the operating frequency, the antenna behaves as a loop, the radiation response having nulls directed generally perpendicularly on each side of a plane containing the central axis of the core and the connections of the 6 helical elements with the feeder structure and with the conductive sleeve. The antenna is intended primarily for a handheld communication unit such as a cellular or cordless telephone handset, the presence of the nulls in the radiation pattern reducing radiation into the user's head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.