US3820117A - Frequency extension of circularly polarized antenna - Google Patents

Frequency extension of circularly polarized antenna Download PDF

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Publication number
US3820117A
US3820117A US00318137A US31813772A US3820117A US 3820117 A US3820117 A US 3820117A US 00318137 A US00318137 A US 00318137A US 31813772 A US31813772 A US 31813772A US 3820117 A US3820117 A US 3820117A
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antenna
cavity
spiral
wide band
assembly
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Expired - Lifetime
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US00318137A
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R Hall
R Johnson
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Bendix Corp
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Bendix Corp
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Priority to US00318137A priority Critical patent/US3820117A/en
Priority to IL43841A priority patent/IL43841A/en
Priority to DE2362913A priority patent/DE2362913C3/en
Priority to GB5873773A priority patent/GB1388230A/en
Priority to FR7345897A priority patent/FR2211767B1/fr
Priority to JP49004602A priority patent/JPS5746241B2/ja
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Publication of US3820117A publication Critical patent/US3820117A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H01Q9/27—Spiral antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/40—Radiating elements coated with or embedded in protective material
    • H01Q1/405—Radome integrated radiating elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/29—Combinations of different interacting antenna units for giving a desired directional characteristic

Definitions

  • the lower range of useful frequency response is thereby changed from a minimum operating frequency wherein the diameter of the spiral tracks constitutes approximately one-half wave length to a value wherein one-half wave length is approximately equal to the width of the antenna elements including the dipoles.
  • This composite structure may be curved to some degree to enable it to conform to the inside surface of a curved radome.
  • This invention relates to circularly polarized, cavitybacked microwave spiral antennas and more particularly to a method and structure for providing a linearly polarized low-frequency extension of the antennas operation.
  • radar warning direction finding systems use circularly polarized, cavity-backed spiral antenna elements operating in the axial mode and producing a cosine pattern.
  • this mode of operation maximum radiation will occur along a line normal to the plane of the spiral element. If a reflecting cavity is placed behind the spiral element, a single lobed radiation pattern perpendicular to the plane of the spiral exists.
  • the present invention is concerned with an extension of this mode of operation into lower frequency bands and with response to left and right-hand circular polarization, as well as linear polarizations and dominantly horizontal polarizations at lower frequency bands.
  • the generally accepted theoretical basis for operation of the spiral antenna is the current band theory. If a spiral antenna is fed so that energy entering the two spiral tracks at the origin is 180 out of phase, the first current band will occur where current in one arm returns to an in-phase condition with the other arm. This condition will occur because of the geometry of the spiral element; that is, each successive turn of the spiral progressively is longer. Analysis indicates that current in adjacent conductors will reach an in-phase condition where the circumference of the ring is equal to one wave length.
  • the generally accepted approach is to increase the diameter of the antenna until the circumference equals one wave length at the lowest frequency required. This approach is incompatible with the need to extend operating frequencies without major modifications of the existing antenna sites.
  • the applicants approach herein depends upon using a spiral antenna whose feed systems provide the 180 phase difference for a suitable band width to satisfy both the initial frequency and the extended (lower) frequencies.
  • the outside ends of the cavity-backed spiral elements are extended by the integration of a cavity-backed dipole element whose effective aperture approximates one half wave length at the lowest required operating frequency.
  • the selected sense of a dominant linear polarization is optional and is determined by the orientation of the dipole elements with respect to the radius vector from the origin of the spiral elements.
  • FIG. 1 is a perspective view of an extended frequency range antenna according to our invention.
  • FIG. 2 is a schematic diagram of the antenna of FIG. 1.
  • FIG. 3 is a view of a typical radome, shown partly in section, with our antenna installed.
  • a planar spiral microwave antenna element 10 having two separate interlaced spiral tracks 10a and 10b is normally formed as a printed circuit on a substrate of insulating material.
  • Antenna element 10 is positioned overlying a microwave cavity consisting of a cylindrical container 12 which is normally lined internally with microwave absorber material which may be held in place by plastic foam material. Details of the construction of a similar cavitybacked microwave antenna appear in U.S. Pat. No. 3,441,937 (common assignee).
  • dipole elements 14a and 14b Wired to the outside ends of each of conductor tracks 10a and 1012 are dipole elements 14a and 14b.
  • Each of dipole elements 14a and 14b is physically positioned on an insulating substrate 16a and 16b, respectively, supported on housings 18a and 18b which constitute extensions of the microwave cavity housing 12. These housings are also lined with microwave absorber material.
  • FIG. 2 is a schematic drawing showing some of the electrical properties of the device'of FIG. 1.
  • a pair of conductors 20 and 22 are connected to the antenna element with conductor 20 connected to spiral track 10a and conductor 22 connected to spiral track 10b. These conductors are normally supplied through a coaxial connector having a shield 24.
  • the dipole elements 140 and 14b are connected to the spiral elements and 10b, respectively, as described above, and these are held physically displaced from the back side of the cavity element 12. In the space between cavity 12 and elements 10a, 10b, 14a and 14b is placed a layer of microwave absorber material.
  • FIG. 3 a radome 25 which is partially broken away to show the antenna installation against its inside wall.
  • the insulating substrate for the antenna element 10 is formed in a dome-shaped configuration to minimize the air space between the antenna surface and the interior surface of the radome 25.
  • the dipole extensions 14a and 14b are positioned against the inside surface of the radome and therefore curved to follow its configuration.
  • Attached to the lower part of housing 12 are metal plates 26a and 26b which constitute ground plane elements for the dipole antenna elements 14a and 14b, respectively.
  • Located between ground plane element 28a and antenna element 14a is a layer of material which may be all microwave absorber material or partially microwave absorber material and partially a plastic foam material which is used as a spacer.
  • a spacer 30 of flexible compressible material may be used between these members.
  • Such a spacer may be made of silicon rubber or other suitable material having dielectric characteristics very similar to that of the radome material.
  • a wide band microwave antenna assembly comprising:
  • a planar spiral antenna mounted on a substrate of insulating material, said antenna including a pair of interlaced spiral elements having terminals near the axis of said assembly,
  • a lower frequency linearly polarized antenna extension comprising a cavity-backed dipole element electrically connected to the outside ends of each of said spiral elements.
  • a wide band microwave antenna assembly com prising
  • an antenna element overlying said cavity including a substrate of insulating material and a pair of interlaced spiral antenna tracks fixed to said substrate,
  • a lower frequency extension comprising a cavity backed dipole element connected to the outside end of each of said tracks such that the overall width of the assembly is approximately one-half wave length at the lowest frequency for which the antenna is expected to provide significant gain.
  • a wide band antenna assembly as set forth in claim 2 wherein said cavity and the cavities backing said dipole elements are lined with microwave absorber material.

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Abstract

The frequency response of a cavity-backed planar microwave antenna having an element including a pair of spiral antenna tracks fixed to a substrate of insulating material is substantially extended by connecting a pair of cavity-backed outwardly extending dipole elements to the outer ends of each of said spiral tracks. The lower range of useful frequency response is thereby changed from a minimum operating frequency wherein the diameter of the spiral tracks constitutes approximately one-half wave length to a value wherein one-half wave length is approximately equal to the width of the antenna elements including the dipoles. This composite structure may be curved to some degree to enable it to conform to the inside surface of a curved radome.

Description

United States Patent [191 Hall et al,
[ June 25, 1974 FREQUENCY EXTENSION OF CIRCULARLY POLARIZED ANTENNA [75] Inventors: Roger D. Hall, Encino; Robert P.
Johnson, Granda Hills, both of Calif.
[73] Assignee: The Bendix Corporation, North Hollywood, Calif.
[22] Filed: Dec. 26, 1972 [21] Appl. No.: 318,137
[52] US. Cl 343/802, 343/806, 343/895 [51] Int. Cl H0lq 9/26, l-lOlq 1/38 [58] Field of Search 343/802, 806, 789, 895
[56] References Cited UNITED STATES PATENTS 2,495,399 l/l950 Wheeler 343/895 FOREIGN PATENTS OR APPLICATIONS 411,888 7/1945 Italy 343/895 Primary ExaminerEli Lieberman Assistant ExaminerWm. H. Punter Attorney, Agent, or Firm-Robert C. Smith ABSTRACT The frequency response of a cavity-backed planar microwave antenna having an element including a pair of spiral antenna tracks fixed to a substrate of insulating material is substantially extended by connecting a pair of cavity-backed outwardly extending dipole elements to the outer ends of each of said spiral tracks. The lower range of useful frequency response is thereby changed from a minimum operating frequency wherein the diameter of the spiral tracks constitutes approximately one-half wave length to a value wherein one-half wave length is approximately equal to the width of the antenna elements including the dipoles. This composite structure may be curved to some degree to enable it to conform to the inside surface of a curved radome.
6 Claims, 3 Drawing Figures This invention relates to circularly polarized, cavitybacked microwave spiral antennas and more particularly to a method and structure for providing a linearly polarized low-frequency extension of the antennas operation. I
For radar warning direction-finding systems installed on aircraft and using remotely located antennas, particularly those installed adjacent to radome structures, it occasionally becomes necessary to extend operating frequencies into lower frequencies without major modifications of the existing antenna locations and radome configurations. In addition to extending the low frequency response of the existing circularly polarized spiral antennas, there may also be a requirement for response to left and right circular polarization, linear polarization and dominantly horizontally polarized lower frequencies.
In most applications, radar warning direction finding systems use circularly polarized, cavity-backed spiral antenna elements operating in the axial mode and producing a cosine pattern. In this mode of operation, maximum radiation will occur along a line normal to the plane of the spiral element. If a reflecting cavity is placed behind the spiral element, a single lobed radiation pattern perpendicular to the plane of the spiral exists. The present invention is concerned with an extension of this mode of operation into lower frequency bands and with response to left and right-hand circular polarization, as well as linear polarizations and dominantly horizontal polarizations at lower frequency bands.
For the axial mode, the generally accepted theoretical basis for operation of the spiral antenna is the current band theory. If a spiral antenna is fed so that energy entering the two spiral tracks at the origin is 180 out of phase, the first current band will occur where current in one arm returns to an in-phase condition with the other arm. This condition will occur because of the geometry of the spiral element; that is, each successive turn of the spiral progressively is longer. Analysis indicates that current in adjacent conductors will reach an in-phase condition where the circumference of the ring is equal to one wave length.
To extend the lower frequency capability of the cavity-backed spiral antenna, the generally accepted approach is to increase the diameter of the antenna until the circumference equals one wave length at the lowest frequency required. This approach is incompatible with the need to extend operating frequencies without major modifications of the existing antenna sites.
The applicants approach herein depends upon using a spiral antenna whose feed systems provide the 180 phase difference for a suitable band width to satisfy both the initial frequency and the extended (lower) frequencies.
The outside ends of the cavity-backed spiral elements are extended by the integration of a cavity-backed dipole element whose effective aperture approximates one half wave length at the lowest required operating frequency. The selected sense of a dominant linear polarization is optional and is determined by the orientation of the dipole elements with respect to the radius vector from the origin of the spiral elements.
In the drawings:
FIG. 1 is a perspective view of an extended frequency range antenna according to our invention.
FIG. 2 is a schematic diagram of the antenna of FIG. 1.
FIG. 3 is a view of a typical radome, shown partly in section, with our antenna installed.
Referring now to FIG. I, a planar spiral microwave antenna element 10 having two separate interlaced spiral tracks 10a and 10b is normally formed as a printed circuit on a substrate of insulating material. Antenna element 10 is positioned overlying a microwave cavity consisting of a cylindrical container 12 which is normally lined internally with microwave absorber material which may be held in place by plastic foam material. Details of the construction of a similar cavitybacked microwave antenna appear in U.S. Pat. No. 3,441,937 (common assignee). Wired to the outside ends of each of conductor tracks 10a and 1012 are dipole elements 14a and 14b. Each of dipole elements 14a and 14b is physically positioned on an insulating substrate 16a and 16b, respectively, supported on housings 18a and 18b which constitute extensions of the microwave cavity housing 12. These housings are also lined with microwave absorber material.
FIG. 2 is a schematic drawing showing some of the electrical properties of the device'of FIG. 1. A pair of conductors 20 and 22 are connected to the antenna element with conductor 20 connected to spiral track 10a and conductor 22 connected to spiral track 10b. These conductors are normally supplied through a coaxial connector having a shield 24. The dipole elements 140 and 14b are connected to the spiral elements and 10b, respectively, as described above, and these are held physically displaced from the back side of the cavity element 12. In the space between cavity 12 and elements 10a, 10b, 14a and 14b is placed a layer of microwave absorber material.
In FIG. 3 is shown a radome 25 which is partially broken away to show the antenna installation against its inside wall. In this installation the insulating substrate for the antenna element 10 is formed in a dome-shaped configuration to minimize the air space between the antenna surface and the interior surface of the radome 25. The dipole extensions 14a and 14b are positioned against the inside surface of the radome and therefore curved to follow its configuration. Attached to the lower part of housing 12 are metal plates 26a and 26b which constitute ground plane elements for the dipole antenna elements 14a and 14b, respectively. Located between ground plane element 28a and antenna element 14a is a layer of material which may be all microwave absorber material or partially microwave absorber material and partially a plastic foam material which is used as a spacer. Similar material is shown at 28b between ground plane 26b and antenna element 1412. To take up any possible remaining air space between the surface of antenna element 10 and the interior surface of the radome 25, a spacer 30 of flexible compressible material may be used between these members. Such a spacer may be made of silicon rubber or other suitable material having dielectric characteristics very similar to that of the radome material.
While only a single embodiment is shown and de scribed herein, modifications may be made to suit certain particular installations. The curved arrangement shown in FIG. 3 causes a flattening or broadening of the antenna characteristic but otherwise has little effeet. From the foregoing, it will be appreciated that applicants have provided an antenna structure which con- I 1. A wide band microwave antenna assembly comprising:
a planar spiral antenna mounted on a substrate of insulating material, said antenna including a pair of interlaced spiral elements having terminals near the axis of said assembly,
a cavity structure of generally cylindrical configuration supporting said antenna element and positioned at the back of said planar spiral antenna,
and a lower frequency linearly polarized antenna extension comprising a cavity-backed dipole element electrically connected to the outside ends of each of said spiral elements.
2. A wide band microwave antenna assembly com prising:
a cylindrical cavity,
an antenna element overlying said cavity including a substrate of insulating material and a pair of interlaced spiral antenna tracks fixed to said substrate,
and a lower frequency extension comprising a cavity backed dipole element connected to the outside end of each of said tracks such that the overall width of the assembly is approximately one-half wave length at the lowest frequency for which the antenna is expected to provide significant gain.
3. A wide band antenna assembly as set forth in claim 2 wherein said cavity and the cavities backing said dipole elements are lined with microwave absorber material.
4. A wide band antenna assembly as set forth in claim 2 wherein said spiral track and said dipole elements are conformed to fit against a rounded radome structure.
quencies received.

Claims (6)

1. A wide band microwave antenna assembly comprising: a planar spiral antenna mounted on a substrate of insulating material, said antenna including a pair of interlaced spiral elements having terminals near the axis of said assembly, a cavity structure of generally cylindrical configuration supporting said antenna element and positioned at the back of said planar spiral antenna, and a lower frequency linearly polarized antenna extension comprising a cavity-backed dipole element electrically connected to the outside ends of each of said spiral elements.
2. A wide band microwave antenna assembly comprising: a cylindrical cavity, an antenna element overlying said cavity including a substrate of insulating material and a pair of interlaced spiral antenna tracks fixed to said substrate, and a lower frequency extension comprising a cavity-backed dipole element connected to the outside end of each of said tracks such that the overall width of the assembly is approximately one-half wave length at the lowest frequency for which the antenna is expected to provide significant gain.
3. A wide band antenna assembly as set forth in claim 2 wherein said cavity and the cavities backing said dipole elements are lined with microwave absorber material.
4. A wide band antenna assembly as set forth in claim 2 wherein said spiral track and said dipole elements are conformed to fit against a rounded radome structure.
5. A wide band antenna assembly as set forth in claim 2 wherein said substrate is dome-shaped and said dipole elements are curved.
6. A wide band antenna assembly as set forth in claim 2 wherein the height of said antenna tracks and dipole members from the back walls of their respective cavities is less than one-quarter wave length over the frequencies received.
US00318137A 1972-12-26 1972-12-26 Frequency extension of circularly polarized antenna Expired - Lifetime US3820117A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US00318137A US3820117A (en) 1972-12-26 1972-12-26 Frequency extension of circularly polarized antenna
IL43841A IL43841A (en) 1972-12-26 1973-12-17 Frequency extension of circularly polarized antenna
DE2362913A DE2362913C3 (en) 1972-12-26 1973-12-18 Spiral antenna
GB5873773A GB1388230A (en) 1972-12-26 1973-12-19 Frequency extension of circularly polarized antenna
FR7345897A FR2211767B1 (en) 1972-12-26 1973-12-21
JP49004602A JPS5746241B2 (en) 1972-12-26 1973-12-25

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DE (1) DE2362913C3 (en)
FR (1) FR2211767B1 (en)
GB (1) GB1388230A (en)
IL (1) IL43841A (en)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4012744A (en) * 1975-10-20 1977-03-15 Itek Corporation Helix-loaded spiral antenna
US4015264A (en) * 1975-11-20 1977-03-29 Textron, Inc. Dual mode broadband antenna
FR2323244A1 (en) * 1975-09-08 1977-04-01 American Electronic Lab WIDE BAND ANTENNA
US4042935A (en) * 1974-08-01 1977-08-16 Hughes Aircraft Company Wideband multiplexing antenna feed employing cavity backed wing dipoles
US4114164A (en) * 1976-12-17 1978-09-12 Transco Products, Inc. Broadband spiral antenna
US4268833A (en) * 1978-09-08 1981-05-19 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence Broadband shaped beam antenna employing a cavity backed spiral radiator
US4309706A (en) * 1974-11-14 1982-01-05 The United States Of America As Represented By The Secretary Of The Navy Wideband direction-finding system
US4348677A (en) * 1979-06-25 1982-09-07 General Dynamics, Pomona Division Common aperture dual mode seeker antenna
WO1992013372A1 (en) * 1991-01-24 1992-08-06 Rdi Electronics, Inc. Broadband antenna
BE1011665A5 (en) * 1989-08-03 1999-12-07 Dassault Electronique An improved spiral antennas
US6104353A (en) * 1998-06-30 2000-08-15 Rdi Electronics, Inc. Local television antenna system for use with direct broadcast satellite television systems
WO2000079645A1 (en) 1999-06-18 2000-12-28 Telefonaktiebolaget Lm Ericsson (Publ) Tuneable spiral antenna
WO2002009230A1 (en) * 2000-07-20 2002-01-31 Samsung Electronics, Ltd Antenna
US20040027308A1 (en) * 2002-06-10 2004-02-12 Lynch Jonathan J. Low profile, dual polarized/pattern antenna
US20050243014A1 (en) * 2004-05-03 2005-11-03 Bryan John W Jr Ground proximity antenna system
WO2015007726A1 (en) * 2013-07-19 2015-01-22 Plath Gmbh Assembly and method for installing a direction-finding antenna in a radome, preferably for retrofitting a direction-finding antenna in a radome
US10992046B2 (en) * 2019-06-12 2021-04-27 Bae Systems Information And Electronic Systems Integration Inc. Low profile high gain dual polarization UHF/VHF antenna

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58974Y2 (en) * 1976-11-19 1983-01-08 防衛庁技術研究本部長 antenna equipment
US4697192A (en) * 1985-04-16 1987-09-29 Texas Instruments Incorporated Two arm planar/conical/helix antenna
EP0280644A3 (en) * 1987-02-26 1989-03-01 Schumacher, Hanns-Joachim, Dr. med. dent. Arrangement for detecting and/or influencing electromagnetic waves, method of making the arrangement and antenna for carrying out the method and for setting up the arrangement
FR2665324B1 (en) * 1990-07-27 1996-08-14 Thomson Csf METHOD FOR MANUFACTURING PRINTED CIRCUIT AND CIRCUIT OBTAINED BY THIS PROCESS.

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4042935A (en) * 1974-08-01 1977-08-16 Hughes Aircraft Company Wideband multiplexing antenna feed employing cavity backed wing dipoles
US4309706A (en) * 1974-11-14 1982-01-05 The United States Of America As Represented By The Secretary Of The Navy Wideband direction-finding system
FR2323244A1 (en) * 1975-09-08 1977-04-01 American Electronic Lab WIDE BAND ANTENNA
US4032921A (en) * 1975-09-08 1977-06-28 American Electronic Laboratories, Inc. Broad-band spiral-slot antenna
DE2642013A1 (en) * 1975-10-20 1977-05-05 Itek Corp ANTENNA ARRANGEMENT
US4012744A (en) * 1975-10-20 1977-03-15 Itek Corporation Helix-loaded spiral antenna
US4015264A (en) * 1975-11-20 1977-03-29 Textron, Inc. Dual mode broadband antenna
US4114164A (en) * 1976-12-17 1978-09-12 Transco Products, Inc. Broadband spiral antenna
US4268833A (en) * 1978-09-08 1981-05-19 Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National Defence Broadband shaped beam antenna employing a cavity backed spiral radiator
US4348677A (en) * 1979-06-25 1982-09-07 General Dynamics, Pomona Division Common aperture dual mode seeker antenna
BE1011665A5 (en) * 1989-08-03 1999-12-07 Dassault Electronique An improved spiral antennas
WO1992013372A1 (en) * 1991-01-24 1992-08-06 Rdi Electronics, Inc. Broadband antenna
US5257032A (en) * 1991-01-24 1993-10-26 Rdi Electronics, Inc. Antenna system including spiral antenna and dipole or monopole antenna
US5457469A (en) * 1991-01-24 1995-10-10 Rdi Electronics, Incorporated System including spiral antenna and dipole or monopole antenna
US6104353A (en) * 1998-06-30 2000-08-15 Rdi Electronics, Inc. Local television antenna system for use with direct broadcast satellite television systems
US6335710B1 (en) 1999-06-18 2002-01-01 Telefonaktiebolaget Lm Ericsson (Publ) Tuneable spiral antenna
WO2000079645A1 (en) 1999-06-18 2000-12-28 Telefonaktiebolaget Lm Ericsson (Publ) Tuneable spiral antenna
US7015874B2 (en) * 2000-07-20 2006-03-21 Samsung Electronics Co., Ltd Antenna
WO2002009230A1 (en) * 2000-07-20 2002-01-31 Samsung Electronics, Ltd Antenna
US20040032376A1 (en) * 2000-07-20 2004-02-19 Ikramov Gairat Saidkhakimovich Antenna
US6784853B2 (en) * 2000-07-20 2004-08-31 Samsung Electronics Co., Ltd. Antenna
AU2001258958B2 (en) * 2000-07-20 2004-10-07 Samsung Electronics Co., Ltd Antenna
US20040227689A1 (en) * 2000-07-20 2004-11-18 Samsung Electronics Co., Ltd. Antenna
US20040027308A1 (en) * 2002-06-10 2004-02-12 Lynch Jonathan J. Low profile, dual polarized/pattern antenna
US6864856B2 (en) * 2002-06-10 2005-03-08 Hrl Laboratories, Llc Low profile, dual polarized/pattern antenna
US20050243014A1 (en) * 2004-05-03 2005-11-03 Bryan John W Jr Ground proximity antenna system
US7199763B2 (en) * 2004-05-03 2007-04-03 Lockheed Martin Corporation Ground proximity antenna system
WO2015007726A1 (en) * 2013-07-19 2015-01-22 Plath Gmbh Assembly and method for installing a direction-finding antenna in a radome, preferably for retrofitting a direction-finding antenna in a radome
US10992046B2 (en) * 2019-06-12 2021-04-27 Bae Systems Information And Electronic Systems Integration Inc. Low profile high gain dual polarization UHF/VHF antenna

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Publication number Publication date
JPS5746241B2 (en) 1982-10-02
IL43841A (en) 1976-05-31
DE2362913C3 (en) 1979-08-16
JPS4998558A (en) 1974-09-18
GB1388230A (en) 1975-03-26
FR2211767B1 (en) 1979-05-04
FR2211767A1 (en) 1974-07-19
IL43841A0 (en) 1974-03-14
DE2362913A1 (en) 1974-06-27
DE2362913B2 (en) 1978-12-21

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