US2511662A - Permeability tuned loop antenna circuit - Google Patents

Permeability tuned loop antenna circuit Download PDF

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Publication number
US2511662A
US2511662A US573896A US57389645A US2511662A US 2511662 A US2511662 A US 2511662A US 573896 A US573896 A US 573896A US 57389645 A US57389645 A US 57389645A US 2511662 A US2511662 A US 2511662A
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US
United States
Prior art keywords
circuit
loop antenna
primary
inductance
transformer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US573896A
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English (en)
Inventor
William S Bachman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co filed Critical General Electric Co
Priority to US573896A priority Critical patent/US2511662A/en
Priority to BE480380A priority patent/BE480380R/fr
Application granted granted Critical
Publication of US2511662A publication Critical patent/US2511662A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H2/00—Networks using elements or techniques not provided for in groups H03H3/00 - H03H21/00
    • H03H2/005—Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers
    • H03H2/008—Receiver or amplifier input circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type
    • H01F17/04—Fixed inductances of the signal type with magnetic core
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F21/00—Variable inductances or transformers of the signal type
    • H01F21/02—Variable inductances or transformers of the signal type continuously variable, e.g. variometers
    • H01F21/06—Variable inductances or transformers of the signal type continuously variable, e.g. variometers by movement of core or part of core relative to the windings as a whole

Definitions

  • Fig. 1 is a portion of a radio frequency circuit employing a permeability tuned loop antenna
  • Fig. 2 is a curve which shows the relation between the gain factor and the coupling between the primary and the secondary windings of the transformer used in the circuit of Fig. 1
  • Fig. 3 is a cross-sectional view of a transformer which may be employed in the circuit of Fig. 1
  • Fig. 4 is a modification of the transformer suitable for use in the circuit of Fig. 1
  • Fig. 5 is a. curve showing the gain and tuning characteristic of the circuit of Fig. 1.
  • a radio frequency circuit there shown includes a loop antenna I which is connected in series with the primary winding 2 of a permeability tuned transformer 3.
  • the transformer 3 includes a secondary winding 4 which is tightly coupled to the primary winding 2 and which is tuned by means of a movable powdered iron core 5.
  • the resonant circuit of the secondary winding 4 includes a capacitance 6 and the output terminal of the circuit is shown as connected to the control electrode of an electron discharge device I.
  • both the loop antenna I be constituted by a few turns of wire and the primary winding 2 of the transformer comprise a small number of turns so that the capacitive coupling between the primary and secondary circuits is kept at a small value. It has been observed further that optimum results are obtained by closely coupling the primary winding 2 to the secondary winding 4 and by keeping the primary inductance substantially constant over the entire tuning range of the circuit so that the tuning range of the cou led circuits issubstantially the same as that of the secondary circuit alone.
  • a maximum gain factor for the overall circuit may be obtained.
  • the maximum realizable coupling K1 between the primary winding 2 and the secondary winding 4 should be employed, where M K l V P Z
  • L2 the required value of L2 is found from the range of frequencies to be covered, the value of capacitive reactance in the secondary circuit, and theoverall coupling coefficient, 1. e.,
  • La for a low impedance input circuit is a small inductance, for maximum gainin the antenna cirwit the totalinductanceLi is distributed between the inductance Lo of, loop I and the in,- ductance Lp of rimary winding. 2 by making L of thesame order and slightly'less than Lo.
  • the secondary winding 4 is wound as a. solenoid on a dielectric form 8 and the primary winding. 2 is woundon one end of the tuning core 9. formed'ofcompressed powdered iron particles.
  • the core 9 at its, left-hand end has a shoulder portion-I0 upon. which theprirnary winding 2 is wound. It has been found in the use of-H-a transformer of this constructionthat, as thetuning of, thesecondary circuit is varied-over itscompletecrange, the inductance of the primary circuit is maintained substantially constant'and that-the coupling coefficient of the primary circuit is likewise maintained substantially constant.
  • Fig. 4 illustrates another form of the transformer construction which is suitable for use in the ,circuit of Fig. 1.
  • the secondary winding 4 a closely wound solenoid supported on a dielectric form H and the primary windin 2 is wound adjacent to the secondary winding on the form I I at the end into which the tuning core I2 enters.
  • the inductance of. the primary circuit varies by about 2: 1, depending upon the position of the core 2,, and the tuning range of the circuit is extended :by allowing the core, lj2gtopass out of the primary coil 2 and lie whollyc withinthe secondary coil 4.
  • Fig. 5 illustrates the .gain, and tunin characteristics of the circuit, of Fig. 1 employing the transformer construction shown in Fig. [In the circuit having the characteristics indicated by the curves orrig. 5, the inductanceofwind ing 4 with the tuning core completely removed was approximately 142.4 microhenries, the inductance of the winding 2 was one microhenry, the inductance of the loop antenna I was 2 microhenries, and the capacitor 6 had a value of 58 mmfd.
  • curve [3 shows that the gain characteristic of the circuit as its tuned frequency is varied over the normal broadcast range by displacement of the position of the core 9 within the winding 4 is at all points quite high and has an overall variation of not more than 2:1.
  • Curve I4 shows the displacement of the core with frequency and illustrates the tuning characteristic of the circuit.
  • aradio receiver the combination of a loop antenna, a transformer having, a primary winding serially connected with said antenna, said transformer comprising a tubular dielectric member, said primary Winding being supported on said member, ,a secondary winding supported on said member closely adjacent said primary winding and closely coupled therewith magnetically and so. arranged that the capacitive coupling therewith is minimized, and a magnetic core movable within said member and magnetically coupled to both of said windings for varying the inductance of said secondary winding while maintaining the. inductance ofsaid primary winding substantially constant, said primary winding having an inductance of the same order of but less than the inductance of said loop antenna.
  • a radio receiver the combination of a loop antenna, a transformer having a primary circuit comprising a .primary winding serially connected withsaid antenna, said transformer having a secondary winding closely coupled to saidu primary winding, the inductance of said primary winding totheinductance of said primary, circuitbeing proportional.
  • K:and Kisare thecoupling coefficients of said secondary winding to said: primary circuit and said primary windingxrespectively, and means comprising a. movable core member magnetically coupled toboth of said'windings for varying the inductance ofsaid-secondary winding while maintaining' the inductance of saidprimary circuit and said primary winding substantially constant.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Details Of Aerials (AREA)
US573896A 1945-01-19 1945-01-19 Permeability tuned loop antenna circuit Expired - Lifetime US2511662A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US573896A US2511662A (en) 1945-01-19 1945-01-19 Permeability tuned loop antenna circuit
BE480380A BE480380R (enrdf_load_stackoverflow) 1945-01-19 1948-02-14

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US573896A US2511662A (en) 1945-01-19 1945-01-19 Permeability tuned loop antenna circuit

Publications (1)

Publication Number Publication Date
US2511662A true US2511662A (en) 1950-06-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
US573896A Expired - Lifetime US2511662A (en) 1945-01-19 1945-01-19 Permeability tuned loop antenna circuit

Country Status (2)

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US (1) US2511662A (enrdf_load_stackoverflow)
BE (1) BE480380R (enrdf_load_stackoverflow)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2663789A (en) * 1950-08-12 1953-12-22 Westinghouse Electric Corp Heat-treatment apparatus
US2709219A (en) * 1951-11-20 1955-05-24 Du Mont Allen B Lab Inc High-frequency transformer and circuit
US2754415A (en) * 1950-10-09 1956-07-10 Du Mont Allen B Lab Inc Receiver antenna coupling circuit for balanced or unbalanced input
US2765120A (en) * 1953-08-13 1956-10-02 John P Mascolo Radiator enclosure
US2925495A (en) * 1958-01-06 1960-02-16 Aladdin Ind Inc Tuner with primary coil on moving sleeve
US3016537A (en) * 1957-07-09 1962-01-09 Telefunken Gmbh Direction finder antenna system
US11322294B2 (en) * 2018-04-25 2022-05-03 Tdk Corporation Coil component

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1854915A (en) * 1928-01-23 1932-04-19 Rca Corp Radio receiving system
US2111373A (en) * 1935-03-07 1938-03-15 Johnson Lab Inc Permeability-tuned device
US2267047A (en) * 1940-02-19 1941-12-23 Johnson Lab Inc Signal collecting system for radio receivers and the like
US2283926A (en) * 1938-05-31 1942-05-26 Rca Corp Coupling method and apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1854915A (en) * 1928-01-23 1932-04-19 Rca Corp Radio receiving system
US2111373A (en) * 1935-03-07 1938-03-15 Johnson Lab Inc Permeability-tuned device
US2283926A (en) * 1938-05-31 1942-05-26 Rca Corp Coupling method and apparatus
US2267047A (en) * 1940-02-19 1941-12-23 Johnson Lab Inc Signal collecting system for radio receivers and the like

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2663789A (en) * 1950-08-12 1953-12-22 Westinghouse Electric Corp Heat-treatment apparatus
US2754415A (en) * 1950-10-09 1956-07-10 Du Mont Allen B Lab Inc Receiver antenna coupling circuit for balanced or unbalanced input
US2709219A (en) * 1951-11-20 1955-05-24 Du Mont Allen B Lab Inc High-frequency transformer and circuit
US2765120A (en) * 1953-08-13 1956-10-02 John P Mascolo Radiator enclosure
US3016537A (en) * 1957-07-09 1962-01-09 Telefunken Gmbh Direction finder antenna system
US2925495A (en) * 1958-01-06 1960-02-16 Aladdin Ind Inc Tuner with primary coil on moving sleeve
US11322294B2 (en) * 2018-04-25 2022-05-03 Tdk Corporation Coil component

Also Published As

Publication number Publication date
BE480380R (enrdf_load_stackoverflow) 1948-02-28

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