The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 21, 1981
Filed:
Sep. 10, 1979
Donald H Wells, Holland, OH (US);
Other;
Abstract
An electromagnetic tuning device for RF circuits and particularly loading coils for antennas is disclosed. The preferred devices have a coil which produces a generally torroidal shaped electromagnetic field that is intensified by either a core of ferromagnetic material or a second coil inside the other coil. An insulating material surrounds and hermetically seals the coil and field intensifying device that is inside said coil; and an electrically conductive tuning ring is positioned outside of the insulating material for producing a counter magnetic field which opposes and cuts down the field produced by the first mentioned coil. In one embodiment, the tuning ring is threaded and it threadably engages the insulating material so it can be adjustably positioned relative to the torroidal field. In another embodiment the tuning ring is connected in electrical series circuit with a variable resistor. In both embodiments the tuning ring is insulated from ground and the coil so that nonproductive current flow is prevented. In a further embodiment, an electrically conductive shield having magnetic field transmitting windows is positioned between the tuning ring and the coil to greatly reduce capacitive effects on the coil by the environment.