Ferrite-core antenna
US4805232A · kind A · utility
Inventor
Key dates
| Filing date | Jan 15, 1987 |
| Grant date | Feb 14, 1989 |
| Priority date | — |
| Expiry date | Jan 15, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A ferrite core antenna for use in the VHF and UHF range has a first coil on the core which is connected to a capacitance selected to resonate with the inductance of the coil at the desired frequency of operation. The ferrite core antenna also has a second coil for providing a signal to the input stage of a radio receiver. In contrast to conventional loopstick antennas for low frequencies, the operation of the ferrite core antenna in the VHF to UHF range is remarkably improved by using an input stage having a relatively high input impedance and using a greater number of turns in the second coil than the first which is tuned instead of the second. Preferably the first coil is centrally disposed and has a single turn in the form of a relatively wide band of conductive metal foil, and the second coil is offset by a certain distance from the first coil and feeds an input signal to the gate of a gallium arsenide field-effect transistor. For operation in the FM broadcast band, the ferrite core preferably has dimensions of 7 cm.times.1 cm.times.1.5 cm, and the second coil has about three turns. So that the first coil has a sufficiently high Q, the capacitance for resonating the first coil …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.