Extendable antenna for portable cellular telephones with ground radiator
US4868576A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 2, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Nov 2, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q9/30
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An antenna for a portable cellular telephone includes a quarter-wavelength ground radiator and a helical coil capacitively coupled to an extendable half-wavelength radiator. The extendable half-wavelength radiator includes a metallic coil molded in plastic. The ground radiator includes a serpentined transmission line on a flexible circuit board. The helical coil and ground radiator are coupled by a transmission line to a duplexer. The duplexer couples transmitter signals from a radio transmitter to the antenna and receiver signals from the antenna to a radio receiver. The antenna may be advantageously utilized in any portable radio applications where small size and immunity to hand induced radiation losses are desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.