ANTENNA MATCHING NETWORK UTILIZING AN ADJUSTABLE HIGH-POWER INDUCTOR

• US 3,743,974 A
• Filed: 12/22/1971
• Issued: 07/03/1973
• Est. Priority Date: 12/22/1971
• Status: Expired due to Term

• Current Assignee: Berthold Sheffield
• Original Assignee: Berthold Sheffield
• Inventors: Sheffield, Berthold
• Primary Examiner(s): Gensler, Paul L.
• Application Number:
  US05/210,770
• Time in Patent Office: 559 Days
• Field of Search: 333/17 334/4 343/861 336/132,134,135
• US Class Current: 333/17.1
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance

Abstract

An adjustable high-power inductor comprising a toroidal inductance coil having a stationary two-section ferromagnetic core whose confronting ends form a pair of predetermined air-gaps therein. The equivalent reluctance of the magnetic flux path, and thus the inductance, is varied by rotating a disc through the air-gaps and about an axis parallel to the magnetic flux lines generated within the air-gaps. The disc carries a pair of diametrically opposed ferromagnetic members, each having a tapered profile. A reversible motor controls the angular position of the disc, and the angular displacement of the disc determines the equivalent reluctance of the magnetic flux path.

Claims

1. An adjustable inductor, comprising, in combination:

a magnetic core comprising two generally C-shaped core sections forming a toroidal core having two pairs of fixed confronting ends defining two air gaps substantially along a diameter of said toroidal core;

a movable member of magnetic material adapted for movement within said confronting ends, said movable member comprising a nonmagnetic disc having a pair of diametrically opposed magnetic members embedded therein, said disc being mounted on a fixed axis substantially perpendicular to said diameter and adapted for rotation about said axis;

said magnetic core with said movable member providing a magnetic flux path;

means for moving said movable member through said confronting ends;

adjustable flux path means defined by said movable member with the cross-sectional area of said movable member along the direction of its movement varying between a minimum and maximum value wherein the equivalent reluctance of said magnetic flux path varies according to the position of said movable member; and

a winding on said magnetic core with terminals adapted for coupling to an external electrical circuit.

2. The adjustable inductor according to claim 1 wherein said opposed magnetic members each comprise a plurality of stacked sheets of magnetic material forming a laminated magnetic member.

3. The adjustable inductor according to claim 1 wherein said means for moving said member includes a motor having an output means adapted for rotational motion in response to the application of a control signal to said motor and means for translating the rotational motion of said output means to rotational movement of said disc.

4. The adjustable inductor according to claim 3 wherein said motor comprises a reversible motor.

5. The adjustable inductor according to claim 1 wherein said disc includes means for providing minimum effective air-gap within said confronting ends.

6. The adjustable inductor according to claim 5 wherein said opposed magnetic members each comprise a magnetic material having a conductivity significantly less than the conductivity of iron.

7. An antenna matching network including an adjustable reactance tuner having a first terminal adapted for connection to a source of VLF signals and a second terminal adapted for coupling to an antenna, said adjustable reactance tuner including an adjustable inductor comprising:

a magnetic core comprising two generally C-shaped core sections forming a toroidal core having two pairs of fixed confronting ends defining two air gaps substantially along a diameter of said toroiDal core;

a movable member of magnetic material adapted for movement within said confronting ends, said movable member comprising a nonmagnetic disc having a pair of diametrically opposed magnetic members embedded therein, said disc being mounted on a fixed axis substantially perpendicular to said diameter and adapted for rotation about said axis;

said magnetic core with said movable member providing a magnetic flux path;

means for moving said movable member through said confronting ends;

adjustable flux path means defined by said movable member with the cross-sectional area of said member along the direction of its movement varying between a minimum and maximum value, wherein the equivalent reluctance of said magnetic flux path varies according to the position of said movable member; and

a winding on said magnetic core with terminals adapted for coupling between said first and second terminals.

8. The antenna matching network according to claim 7 wherein said means for moving said member includes means coupled to said disc and adapted for rotating said disc in response to phase variations between voltage and current waveforms at said first terminal.

9. The antenna matching network according to claim 8 wherein said adjustable reactance tuner includes a capacitor serially coupled with said adjustable inductor.

10. The antenna matching network according to claim 9 wherein said capacitor exhibits a capacitive reactance whose relative magnitude exceeds the maximum inductive reactance of said adjustable inductor at a given frequency of said VLF signals.

11. An adjustable reactance device comprising in combination:

a magnetic core comprising two generally C-shaped core sections forming a toroidal core having two pairs of fixed confronting ends defining an two air gaps substantially along a diameter of said toroidal core;

a movable member of magnetic material adapted for movement within said confronting ends, said movable member comprising a nonmagnetic disc having a pair of diametrically opposed magnetic members embedded therein, said disc being mounted on a fixed axis substantially perpendicular to said diameter and adapted for rotation about said axis;

said magnetic core with said movable member providing a magnetic flux path;

means for moving said movable member through said confronting ends;

adjustable flux path means defined by said movable member with the cross-sectional area of said movable member along the direction of its movement varying between a minimum and maximum value wherein the equivalent reluctance of said magnetic flux path varies according to the position of said movable member;

a winding on said magnetic core;

at least one fixed capacitor serially coupled with said winding, wherein the capacitive reactance of said capacitor is added to the relative inductive reactance of said winding; and

first and second output terminals, said first output terminal being coupled to one end of said winding and said second output terminal being coupled to one end of said fixed capacitor, said output terminals being adapted for coupling to an external circuit, whereby the resultant reactance at said output terminals varies according to the position of said movable member.

12. The adjustable reactance device according to claim 11 wherein said means for moving said member includes a motor having an output means adapted for rotational motion in response to the application of a control signal to said motor and means for translating the rotational motion of said output means to rotational movement of said disc.