Self isolating high frequency saturable reactor
AssigneeSematech, Inc.
InventorJames A. Moore
Life of this patent
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Abstract
The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.
Claims21
A variable inductor, comprising:
- a plurality of magnetic cores with matching magnetic permeability and saturation flux density characteristics where each core has a physical symmetry and a closed magnetic path;
- a control winding, said control winding is wired in an aiding configuration around said plurality of magnetic cores;
- and
- a RF winding, said RF winding is wired in an opposing configuration using a figure eight configuration around and through said plurality of magnetic cores, said RF winding produces a bootstrapping of interwinding capacitance for said control winding, and said RF winding causes the sum of the induced voltage around each individual turn of said control winding to be zero and the RF potential at each point on a given turn of either of said windings and induced by the other said winding to be the same as at the corresponding point on said windings on either side of the point.
A method of manufacturing a variable inductor, comprising the following steps:
- providing a plurality of magnetic cores with matching magnetic permeability and saturation flux density characteristics where each has a physical symmetry and a closed magnetic path;
- wiring a control winding in an aiding configuration around said plurality of magnetic cores;
- and
- wiring a RF winding in an opposing configuration using a figure eight configuration around and through said plurality of magnetic cores, said RF winding produces a bootstrapping of interwinding capacitance for said control winding and said RF winding causes the sum of the induced voltage around each individual turn of said control winding to be zero and the RF potential at each point on a given turn of either of said windings and induced by the other said winding to be the same as at the corresponding point on said windings on either side of the point.
A process for varying a reactance, comprising the following steps:
- providing a DC current to a control winding, said control winding is wired in an aiding configuration around a plurality of magnetic cores with matching magnetic permeability and saturation flux density characteristics where each core has a physical symmetry and a closed magnetic path;
- and
- providing an AC signal to a RF winding, said RF winding is wired in an opposing configuration using a figure eight configuration around and through said plurality of magnetic cores, said RF winding, produces a bootstrapping of interwinding capacitance for said control winding, and said RF winding causes the sum of the induced voltage around each individual turn of said control winding to be zero and the RF potential at each point on a given turn of either of said windings and induced by the other said winding to be the same as at the corresponding point on said windings on either side of the point.
An apparatus for impedance matching, comprising:
- an impedance transformer for matching a resistance;
- and
- a saturable reactor for matching a reactive impedance coupled to said impedance transformer, said saturable reactor further comprises:
- a plurality of magnetic cores where each core has a physical symmetry and a closed magnetic path;
- a control winding, said control winding is wired in an aiding configuration around said plurality of magnetic cores;
- and
- a RF winding, said RF winding is wired in an opposing configuration through said plurality of magnetic cores.
A process for impedance matching, comprising the following steps:
- providing an AC signal to a matching transformer for matching a resistance, said matching transformer couples to a saturable reactor;
- providing a DC current to a control winding of said saturable reactor, said control winding is wired in an aiding configuration around a plurality of magnetic cores in said saturable reactor where each core has a physical symmetry and a closed magnetic path, said DC current varies a reactive impedance of said saturable reactor;
- and
- providing said AC signal to a RF winding of said saturable reactor for matching said reactive impedance, said RF winding is wired in an opposing configuration through said plurality of magnetic cores of said saturable reactor.
Dependencies are inferred from the claim text.