Antenna having coaxial driven element with grounded center conductor
US4626862A · kind A · utility
Inventor
Key dates
| Filing date | Aug 8, 1984 |
| Grant date | Dec 2, 1986 |
| Priority date | — |
| Expiry date | Aug 8, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q1/243
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An elongated active element for an antenna has an internal resonator providing a high quality matching impedance. The internal resonator is formed by a pair of conductors including an outer conductor and a coaxial inner conductor that is connected to signal ground. The signal connection of the active element is made to one end of the outer conductor in the neighborhood of the ground connection to the inner conductor. The inner conductor is shorted to the outer conductor at approximately a quarter of a wavelength, plus an integral number of half wavelengths, from the signal and ground connections to provide a parallel-resonant condition complementing the series resonant characteristics of the radiation impedance of the active element. Preferably, the active element is approximately a quarter wavelength long, and may be lengthened or shortened to obtain a desired radiation resistance. The antenna is easily fabricated from a length of coaxial cable. The antenna is advantageously used in pagers and other kinds of VHF and UHF radios, since the coaxial cable can be coiled to fit inside a miniature radio housing. For relatively low frequencies, a coil of coaxial cable including a number o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.