US3902177A - Antenna for direction finders - Google Patents

Antenna for direction finders Download PDF

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Publication number
US3902177A
US3902177A US338419A US33841973A US3902177A US 3902177 A US3902177 A US 3902177A US 338419 A US338419 A US 338419A US 33841973 A US33841973 A US 33841973A US 3902177 A US3902177 A US 3902177A
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Prior art keywords
antenna
frequency
loop antenna
conductor
auxiliary conductor
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Expired - Lifetime
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US338419A
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Kenzo Mori
Hyo Yasuda
Yujiro Katsube
Norio Ikeda
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Taiyo Musen Co Ltd
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Taiyo Musen Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/04—Screened antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/378—Combination of fed elements with parasitic elements

Definitions

  • ABSTRACT This invention relates to an antenna for direction finders presenting a high sensitivity in a narrow band by making a loop antenna and a shielding tube resonate at any two desired frequencies.
  • Loop antennas are generally used as directional an tennas for direction finders. It is the general practice to fit such loop antenna with a shielding tube. However, conventional antennas of this kind have a high sensitivity only at a comparatively low frequency. Further, by inserting a condenser between both ends of a loop antenna and making its electrostatic capacitance and the inductance of the antenna resonate with each other, the sensitivity can be increased near the resonating fre quency.
  • An object of the present invention is to provide an antenna for direction finders wherein a suitable electrostatic capacitance is formed also between both ends of another auxiliary conductor arranged near and in parallel with a conductor forming a loop antenna as in the above mentioned shielding tube and said electrostatic capacitance and the inductance of the auxiliary conductor are made to resonate with each other so that a high sensitivity may be again presented at any desired frequency higher than the above mentioned resonating frequency.
  • the drawing is a view showing a wiring of an embodiment of the present invention.
  • a conductor forming a loop antenna 1 is fitted with a shielding tube 2 provided with a cut 3 in the top part.
  • a proper insulator 4 is inserted between the inside surface of the shielding tube 2 and the antenna l.
  • a condenser 5 is inserted between both ends of such loop antenna 1 and a condenser 6 is connected also between both ends of the cut 3 of the shielding tube 2 so as to respectively form proper electrostatic capacitances.
  • Both terminals 7 and 8 of the loop antenna I can be connected with a cable 10 through a transformer. Further, a resistance 11 connects to the secondary side or primary side of the transformer 9.
  • such two loop antennas as are de scribed above are so arranged as to intersect at right angles with each other and are led to a goniometer or the like through respective cables.
  • the shielding tube 2 can be used not only as directly grounded but also without being grounded.
  • suitable electrostatic capacitances 6 and 5 are connected respectively in a cut in the top part. for example, of a shielding tube arranged near and in parallel with a conductor forming a loop antenna and between both ends of the loop antenna.
  • the inductance of the loop antenna l and the electrostatic capacitance 5 between both ends of the loop antenna are resonated with each other at any desired first frequency and the inductance of the shielding tube 2 and the electrostatic capacitance 6 between both ends of the shielding tube are resonated with each other at any higher suitable second frequency so that all members 1 through 9 may resonate at a still higher third frequency.
  • the antenna will have the same sensitivity as of a conventional loop antenna of this kind and the impedance as seen from the terminals 7 and 8 will show an inductivity.
  • the impedance as seen toward the antenna side from the terminals 7 and 8 will become so high that the sensitivity will quickly rise.
  • the impedance will vary to be capacitive from being inductive.
  • the frequency of the arriving waves further increases to a third frequency which is higher than said second frequency at which the electrostatic capacitance by the condenser 6 or the like and the inductance of the shielding tube 2 resonate with each other, the impedance as seen from the terminals 7 and 8 will vary again to be inductive and will resonate with the condenser 5, therefore a large electric current will be induced in said antenna 1 and the receiving sensitivity will increase again.
  • the shielding tube is utilized as an auxiliary Conductor.
  • the loop antenna may be formed of a tubular conductor and an auxiliary conductor may be coaxially arranged within said tubular conductor.
  • An antenna for direction finders comprising a first conductor forming a loop antenna having opposite ends, an auxiliary conductor having a cut at the top thereof arranged near and in parallel with said first conductor, first capacitor means connected between both ends of said loop antenna for providing a resonant circuit with said loop antenna which is resonant at a first frequency and second capacitor means connected between both ends of said out of said auxiliary conductor at the top part of said antenna for providing a resonant circuit with said auxiliary conductor which is resonant at a second frequency higher than said first frequency, the values of inductance of said auxiliary conductor and of capacitance of said second capacitor means being selected with respect to the values of inductance of said loop antenna and of capacitance of said first capacitor means so that at a third frequency higher than said second frequency the combination of said auxiliary conductor and second capacitor means provides inductive impedance of such value as to cooperate with said first capacitor means and cause said loop antenna to be resonant at said third frequency permitting a high sensitivity in each narrow band of said

Abstract

This invention relates to an antenna for direction finders presenting a high sensitivity in a narrow band by making a loop antenna and a shielding tube resonate at any two desired frequencies.

Description

United States Patent 1191 Mori et al.
1 Aug. 26, 1975 1 ANTENNA FOR DIRECTION FINDERS [75] Inventors: Kenzo Mori; I-lyo Yasuda; Yujiro Katsube, all of Tokyo; Norio Ikeda, Ichikawa, all of Japan [73] Assignec: Taiyo Musen Co., Ltd., Tokyo,
Japan [22] Filed: Mar. 6, 1973 [21] Appl. No.: 338,419
[30] Foreign Application Priority Data Sept. 19. 1972 Japan .4 47-93217 [52] US. Cl. 343/741; 343/748; 343/842; 343/846 [51] Int. Cl. HOlq 7/04; HOlq 11/12 [58] Field of Search 343/748, 741744, 343/764, 841-842, 866869 [56] References Cited UNITED STATES PATENTS 2.419.577 4/1947 Libby 343/842 X 2,423,083 7/1947 Daubaras 343/842 2,535,053 12/1950 Ercolino .1 343/748 X FOREIGN PATENTS OR APPLICATIONS 871,799 5/1942 France 343/842 Primary Examiner-James W. Lawrence Assistant ExaminerMarvin Nussbaum Attorney, Agent, or FirmA. W. Breiner [57] ABSTRACT This invention relates to an antenna for direction finders presenting a high sensitivity in a narrow band by making a loop antenna and a shielding tube resonate at any two desired frequencies.
3 Claims, l Drawing Figure ANTENNA FOR DIRECTION FINDERS This invention relates to antennas for direction finders.
Loop antennas are generally used as directional an tennas for direction finders. It is the general practice to fit such loop antenna with a shielding tube. However, conventional antennas of this kind have a high sensitivity only at a comparatively low frequency. Further, by inserting a condenser between both ends of a loop antenna and making its electrostatic capacitance and the inductance of the antenna resonate with each other, the sensitivity can be increased near the resonating fre quency.
An object of the present invention is to provide an antenna for direction finders wherein a suitable electrostatic capacitance is formed also between both ends of another auxiliary conductor arranged near and in parallel with a conductor forming a loop antenna as in the above mentioned shielding tube and said electrostatic capacitance and the inductance of the auxiliary conductor are made to resonate with each other so that a high sensitivity may be again presented at any desired frequency higher than the above mentioned resonating frequency.
The drawing is a view showing a wiring of an embodiment of the present invention.
In the drawing, a conductor forming a loop antenna 1 is fitted with a shielding tube 2 provided with a cut 3 in the top part. A proper insulator 4 is inserted between the inside surface of the shielding tube 2 and the antenna l. A condenser 5 is inserted between both ends of such loop antenna 1 and a condenser 6 is connected also between both ends of the cut 3 of the shielding tube 2 so as to respectively form proper electrostatic capacitances. Both terminals 7 and 8 of the loop antenna I can be connected with a cable 10 through a transformer. Further, a resistance 11 connects to the secondary side or primary side of the transformer 9. In a direction finder, such two loop antennas as are de scribed above are so arranged as to intersect at right angles with each other and are led to a goniometer or the like through respective cables. Further, the shielding tube 2 can be used not only as directly grounded but also without being grounded.
As described above, in the present invention, suitable electrostatic capacitances 6 and 5 are connected respectively in a cut in the top part. for example, of a shielding tube arranged near and in parallel with a conductor forming a loop antenna and between both ends of the loop antenna. The inductance of the loop antenna l and the electrostatic capacitance 5 between both ends of the loop antenna are resonated with each other at any desired first frequency and the inductance of the shielding tube 2 and the electrostatic capacitance 6 between both ends of the shielding tube are resonated with each other at any higher suitable second frequency so that all members 1 through 9 may resonate at a still higher third frequency. Therefore, for arriving electric waves of such low frequency at which the condenser 5 inserted between both ends of the loop antenna presents an impedance high enough, the antenna will have the same sensitivity as ofa conventional loop antenna of this kind and the impedance as seen from the terminals 7 and 8 will show an inductivity. When the frequency of the electric waves increases to a value of said first frequency and the electrostatic capacitance of the condenser 5 and the inductance of the above mentioned loop antenna resonate in parallel with each other, the impedance as seen toward the antenna side from the terminals 7 and 8 will become so high that the sensitivity will quickly rise. When the frequency increases to be so high as to exceed the above mentioned resonating point, the impedance will vary to be capacitive from being inductive. However, if the frequency of the arriving waves further increases to a third frequency which is higher than said second frequency at which the electrostatic capacitance by the condenser 6 or the like and the inductance of the shielding tube 2 resonate with each other, the impedance as seen from the terminals 7 and 8 will vary again to be inductive and will resonate with the condenser 5, therefore a large electric current will be induced in said antenna 1 and the receiving sensitivity will increase again. Therefore, when the diameter of the loop antenna 1, thickness of the shielding tube 2, material of the insulator 4 and capacitances of the condensers 5 and 6 are properly selected in the design so that the loop antenna 1 and the shielding tube 2 may respectively resonate with each other at two desired frequencies, there will be obtained an antenna for direction finders having a high sensitivity at the above mentioned first and third frequencies.
In the above has been explained an embodiment wherein the shielding tube is utilized as an auxiliary Conductor. In order to increase the sensitivity at the lower frequency by reducing the inductance of a loop antenna, it is necessary to enlarge the diameter of the conductor. Therefore, in such case, the loop antenna may be formed of a tubular conductor and an auxiliary conductor may be coaxially arranged within said tubular conductor.
What is claimed is:
1. An antenna for direction finders comprising a first conductor forming a loop antenna having opposite ends, an auxiliary conductor having a cut at the top thereof arranged near and in parallel with said first conductor, first capacitor means connected between both ends of said loop antenna for providing a resonant circuit with said loop antenna which is resonant at a first frequency and second capacitor means connected between both ends of said out of said auxiliary conductor at the top part of said antenna for providing a resonant circuit with said auxiliary conductor which is resonant at a second frequency higher than said first frequency, the values of inductance of said auxiliary conductor and of capacitance of said second capacitor means being selected with respect to the values of inductance of said loop antenna and of capacitance of said first capacitor means so that at a third frequency higher than said second frequency the combination of said auxiliary conductor and second capacitor means provides inductive impedance of such value as to cooperate with said first capacitor means and cause said loop antenna to be resonant at said third frequency permitting a high sensitivity in each narrow band of said first and third frequencies.
2. An antenna according to claim 1 wherein said auxiliary conductor is a shielding tube.
3. An antenna according to claim 1 wherein said loop antenna is formed to be tubular and said auxiliary conductor is coaxially arranged within this tubular conductor so that the sensitivity at said first frequency is increased.

Claims (3)

1. An antenna for direction finders comprising a first conductor forming a loop antenna having opposite ends, an auxiliary conductor having a cut at the top thereof arranged near and in parallel with said first conductor, first capacitor means connected between both ends of said loop antenna for providing a resonant circuit with said loop antenna which is resonant at a first frequency and second capacitor means connected between both ends of said cut of said auxiliary conductor at the top part of said antenna for providing a resonant circuit with said auxiliary conductor which is resonant at a second frequency higher than said first frequency, the values of inductance of said auxiliary conductor and of capacitance of said second capacitor means being selected with respect to the values of inductance of said loop antenna and of capacitance of said first capacitor means so that at a third frequency higher than said second frequency the combination of said auxiliary conductor and second capacitor means provides inductive impedance of such value as to cooperate with said first capacitor means and cause said loop antenna to be resonant at said third frequency permitting a high sensitivity in each narrow band of said first and third frequencies.
2. An antenna according to claim 1 wherein said auxiliary conductor is a shielding tube.
3. An antenna according to claim 1 wherein said loop antenna is formed to be tubular and said auxiliary conductor is coaxially arranged within this tubular conductor so that the sensitivity at said first frequency is increased.
US338419A 1972-09-19 1973-03-06 Antenna for direction finders Expired - Lifetime US3902177A (en)

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JP47093217A JPS5226879B2 (en) 1972-09-19 1972-09-19

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Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4083006A (en) * 1973-07-10 1978-04-04 Agency Of Industrial Science & Technology Loop type standard magnetic field generator
US4288794A (en) * 1979-12-26 1981-09-08 Textron Inc. Shielded loop VOR/ILS antenna system
DE3140319A1 (en) * 1981-10-10 1983-04-21 Klaus 3300 Braunschweig Münter Electrically screened broadband antenna for the in-phase detection of the magnetic components of an alternating electromagnetic field
US4605899A (en) * 1982-10-15 1986-08-12 Thomson Csf Magnetic field sensor using a coaxial line wound into a coil
US4792760A (en) * 1986-02-07 1988-12-20 Thomson-Cgr Reception antenna for optical image formation device using nuclear magnetic resonance
US4816766A (en) * 1985-11-18 1989-03-28 Siemens Aktiengesellschaft Surface coil for examination using a nuclear magnetic resonance apparatus
US4847491A (en) * 1986-06-10 1989-07-11 Etablissement Public De Diffusion Dit: Telediffusion De France Resonant loop current disturbing probe
WO1989007347A1 (en) * 1988-02-04 1989-08-10 Uniscan Ltd. Magnetic field concentrator
FR2636781A1 (en) * 1988-09-16 1990-03-23 Matra Systemes Securite Antenna loop for presence control post, emitting a primary signal in order to receive back personalised signals from responders
EP0371562A1 (en) * 1988-11-28 1990-06-06 N.V. Nederlandsche Apparatenfabriek NEDAP Coil antenna device
US5248989A (en) * 1988-02-04 1993-09-28 Unisan Ltd. Magnetic field concentrator
EP0584882A1 (en) * 1992-08-28 1994-03-02 Philips Electronics Uk Limited Loop antenna
US5363113A (en) * 1987-05-07 1994-11-08 General Electric Cgr S.A. Electromagnetic antenna and excitation antenna provided with such electromagnetic antenna for a nuclear magnetic resonance apparatus
US5485165A (en) * 1994-08-15 1996-01-16 The United States Of America As Represented By The Secretary Of The Army Broadband high efficiency full wave open coaxial stub loop antenna
USH1571H (en) * 1994-06-29 1996-08-06 Hansen; Peder M. Dual-feed, dual-mode antenna for mono-directional pattern
US5751255A (en) * 1996-06-07 1998-05-12 Carter, Jr.; Philip S. Electrically small receiving antennas
WO2001089034A1 (en) * 2000-05-15 2001-11-22 Siemens Transit Telematic Systems Ag Carrier element for an antenna with low hand sensitivity
US6636040B1 (en) 1999-12-17 2003-10-21 Fonar Corporation MRI antenna
US6847210B1 (en) 1999-12-17 2005-01-25 Fonar Corporation MRI antenna
US20060038730A1 (en) * 2004-08-19 2006-02-23 Harris Corporation Litzendraht loop antenna and associated methods
EP1665459A2 (en) * 2003-05-01 2006-06-07 MeadWestvaco Corporation Apparatus for and method of providing an antenna integral balun
US7091843B1 (en) 2002-11-05 2006-08-15 Rajiv Singh Lal Functional and ornamental vehicle accessories
USD535984S1 (en) * 2003-01-06 2007-01-30 Rajiv S. Lal Ring-shaped vehicle accessory
US20070257857A1 (en) * 2003-07-25 2007-11-08 Marino Ronald A Apparatus for and Method of Using a Diversity Antenna
US20100182149A1 (en) * 2004-05-18 2010-07-22 Marino Ronald A Apparatus for and method of using rfid antenna configurations
FR3016246A1 (en) * 2014-01-06 2015-07-10 Commissariat Energie Atomique HIGH FREQUENCY ANTENNA
US10402600B1 (en) * 2017-10-30 2019-09-03 Amazon Technologies, Inc. Mobile tray for performing RFID reads
WO2020131966A1 (en) * 2018-12-17 2020-06-25 Raytheon Company Shielded-loop-resonator based gradiometer probe

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58173912U (en) * 1982-05-18 1983-11-21 八木アンテナ株式会社 tiny antenna
JPS59107144U (en) * 1983-01-07 1984-07-19 沖電気工業株式会社 semiconductor chip container
JPH03265305A (en) * 1990-03-15 1991-11-26 Fuji Electric Co Ltd Dual tuning antenna and signal generator having the antenna

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419577A (en) * 1945-03-12 1947-04-29 Standard Telephones Cables Ltd Antenna system
US2423083A (en) * 1943-03-05 1947-07-01 Standard Telephones Cables Ltd Loop antenna system
US2535053A (en) * 1945-06-05 1950-12-26 Michael D Ercolino Portable radio compass

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2423083A (en) * 1943-03-05 1947-07-01 Standard Telephones Cables Ltd Loop antenna system
US2419577A (en) * 1945-03-12 1947-04-29 Standard Telephones Cables Ltd Antenna system
US2535053A (en) * 1945-06-05 1950-12-26 Michael D Ercolino Portable radio compass

Cited By (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4083006A (en) * 1973-07-10 1978-04-04 Agency Of Industrial Science & Technology Loop type standard magnetic field generator
US4288794A (en) * 1979-12-26 1981-09-08 Textron Inc. Shielded loop VOR/ILS antenna system
DE3140319A1 (en) * 1981-10-10 1983-04-21 Klaus 3300 Braunschweig Münter Electrically screened broadband antenna for the in-phase detection of the magnetic components of an alternating electromagnetic field
US4605899A (en) * 1982-10-15 1986-08-12 Thomson Csf Magnetic field sensor using a coaxial line wound into a coil
US4816766A (en) * 1985-11-18 1989-03-28 Siemens Aktiengesellschaft Surface coil for examination using a nuclear magnetic resonance apparatus
US4792760A (en) * 1986-02-07 1988-12-20 Thomson-Cgr Reception antenna for optical image formation device using nuclear magnetic resonance
US4847491A (en) * 1986-06-10 1989-07-11 Etablissement Public De Diffusion Dit: Telediffusion De France Resonant loop current disturbing probe
US5363113A (en) * 1987-05-07 1994-11-08 General Electric Cgr S.A. Electromagnetic antenna and excitation antenna provided with such electromagnetic antenna for a nuclear magnetic resonance apparatus
US5248989A (en) * 1988-02-04 1993-09-28 Unisan Ltd. Magnetic field concentrator
WO1989007347A1 (en) * 1988-02-04 1989-08-10 Uniscan Ltd. Magnetic field concentrator
FR2636781A1 (en) * 1988-09-16 1990-03-23 Matra Systemes Securite Antenna loop for presence control post, emitting a primary signal in order to receive back personalised signals from responders
EP0371562A1 (en) * 1988-11-28 1990-06-06 N.V. Nederlandsche Apparatenfabriek NEDAP Coil antenna device
EP0584882A1 (en) * 1992-08-28 1994-03-02 Philips Electronics Uk Limited Loop antenna
US5422650A (en) * 1992-08-28 1995-06-06 U.S. Philips Corporation Loop antenna with series resonant circuit and parallel reactance providing dual resonant frequencies
USH1571H (en) * 1994-06-29 1996-08-06 Hansen; Peder M. Dual-feed, dual-mode antenna for mono-directional pattern
US5485165A (en) * 1994-08-15 1996-01-16 The United States Of America As Represented By The Secretary Of The Army Broadband high efficiency full wave open coaxial stub loop antenna
US5751255A (en) * 1996-06-07 1998-05-12 Carter, Jr.; Philip S. Electrically small receiving antennas
US6847210B1 (en) 1999-12-17 2005-01-25 Fonar Corporation MRI antenna
US7573432B1 (en) 1999-12-17 2009-08-11 Fonar Corporation MRI antenna
US6636040B1 (en) 1999-12-17 2003-10-21 Fonar Corporation MRI antenna
EP1158601A1 (en) * 2000-05-15 2001-11-28 Häni Prolectron Ag Support device with an antenna with low sensitivity
WO2001089034A1 (en) * 2000-05-15 2001-11-22 Siemens Transit Telematic Systems Ag Carrier element for an antenna with low hand sensitivity
US6637665B2 (en) 2000-05-15 2003-10-28 Siemens Schweiz Ag Carrier element for an antenna
US8330595B2 (en) 2002-11-05 2012-12-11 Rajiv Lal Functional and ornamental vehicle accessories
US7091843B1 (en) 2002-11-05 2006-08-15 Rajiv Singh Lal Functional and ornamental vehicle accessories
US20070013505A1 (en) * 2002-11-05 2007-01-18 Mr. Rajiv Lai Functional and ornamental vehicle accessories
USD535984S1 (en) * 2003-01-06 2007-01-30 Rajiv S. Lal Ring-shaped vehicle accessory
EP1665459A4 (en) * 2003-05-01 2006-11-22 Meadwestvaco Corp Apparatus for and method of providing an antenna integral balun
EP1665459A2 (en) * 2003-05-01 2006-06-07 MeadWestvaco Corporation Apparatus for and method of providing an antenna integral balun
US20070257857A1 (en) * 2003-07-25 2007-11-08 Marino Ronald A Apparatus for and Method of Using a Diversity Antenna
US7834816B2 (en) 2003-07-25 2010-11-16 Sensormatic Electronics Llc Apparatus for and method of using a diversity antenna
US20100182149A1 (en) * 2004-05-18 2010-07-22 Marino Ronald A Apparatus for and method of using rfid antenna configurations
US7205947B2 (en) * 2004-08-19 2007-04-17 Harris Corporation Litzendraht loop antenna and associated methods
US20060038730A1 (en) * 2004-08-19 2006-02-23 Harris Corporation Litzendraht loop antenna and associated methods
FR3016246A1 (en) * 2014-01-06 2015-07-10 Commissariat Energie Atomique HIGH FREQUENCY ANTENNA
US10402600B1 (en) * 2017-10-30 2019-09-03 Amazon Technologies, Inc. Mobile tray for performing RFID reads
WO2020131966A1 (en) * 2018-12-17 2020-06-25 Raytheon Company Shielded-loop-resonator based gradiometer probe
US11460599B2 (en) 2018-12-17 2022-10-04 Raytheon Company Shielded-loop-resonator based gradiometer probe

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Publication number Publication date
JPS5226879B2 (en) 1977-07-16
JPS4951892A (en) 1974-05-20

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