Broadband ferrite transformer-fed whip antenna
US4028704A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 18, 1975 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | Aug 18, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q9/16
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The feed point of a whip antenna having a length less than one quarter-wavelength at the lowest frequency of operation is raised above a counterpoise ground plane by a short base sleeve. Gain over a 2.5:1 bandwidth of radio frequencies closely approaches the gain of a standard quarter-wavelength antenna without requiring use of power-dissipating resistance loading. A ferrite transformer at the whip antenna feedpoint is utilized to reduce the high anti-resonance impedance of the broadband whip antenna to the characteristic impedance of a coaxial cable transmission system and to minimize the VSWR thereof. The base sleeve raises the antenna resistance at the resonant frequency near the lower end of the bandwidth to make the transformer effective as an impedance matching element over the entire radio frequency band. A pair of the whip antennas are axially aligned and electrically coupled in series to realize a broadband dipole having increased gain. A pair of dipoles are energized in phased relationship to realize even higher gain and directivity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.