US2740113A - Magnetic antenna systems - Google Patents
Magnetic antenna systems Download PDFInfo
- Publication number
- US2740113A US2740113A US264717A US26471752A US2740113A US 2740113 A US2740113 A US 2740113A US 264717 A US264717 A US 264717A US 26471752 A US26471752 A US 26471752A US 2740113 A US2740113 A US 2740113A
- Authority
- US
- United States
- Prior art keywords
- antenna
- magnetic
- core
- coil
- bars
- 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
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Classifications
-
- 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
- H01Q7/06—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 with core of ferromagnetic material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
- F01D5/3023—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses
- F01D5/303—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot
- F01D5/3038—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot the slot having inwardly directed abutment faces on both sides
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/27—Adaptation for use in or on movable bodies
- H01Q1/28—Adaptation for use in or on aircraft, missiles, satellites, or balloons
- H01Q1/286—Adaptation for use in or on aircraft, missiles, satellites, or balloons substantially flush mounted with the skin of the craft
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- Thisinvention relates generally to antenna systems and more particularly to improved arrangements of magnetic antennas which are suitable for use as antennas on mobile craft and other applications Where protruding dimensions must be minimized or eliminated.
- antennas While varying, greatly in detail, are almost universally of the type which. can be described as a conductivity discontinuity disposed in the transmission medium of free space and operating usually with reference to a conducting ground plane,
- the distance between the element and the ground plane is required to be quite large for satisfactory operation and the effective height (i. e. the ratio of terminal voltage to field strength) rapidly approaches zero as this distance decreases.
- the effective height i. e. the ratio of terminal voltage to field strength
- the present invention is directed to the provision of flush mounted antennas which have no projection from the ground plane with which they operate and yet maintain' a useable eifective height as signal translators.
- This ample the aircraft beacon band in the neighborhood of 200 fkilocycles and below, without undue physical size by employing a magnetic antenna element which is embedded in an opening in the conducting ground plane.
- the antenna so formed has been found to produce results which are at least as good as prior art electric antennas and by virtue of the physical arrangement thereof aiford considerably improved structural features, such as the aerodynamic advantages in aircraft applications or the like.
- Another object is to provide a directional antenna suitable for direction finding applications which may be operably located on an aircraft without protruding from the surface thereof.
- Still another object is to provide a flush mounted magnetic antenna system which can be flush mounted on a conducting surface and which is simple and economical to construct and exhibits high sensitivity and reliability in operation.
- a magnetic antenna element such as a dust iron or ferrite bar
- a conducting surface or closely adjacent thereto and suitably coupling signals from the coil wound thereon.
- the invention provides a plurality of radially disposed bars of powdered iron or other suitable high frequency permeable material.
- the radial bars are depressed in a conducting surface having incident thereon an electromagnetic radiation field.
- the coplanar bars and mounting surface therefor provide an ideal aerodynamic surface and such an arrangement, in accordance with the teaching of the present invention, is without deleterious effect antenna.
- the bars are disposed with respect to a central opening in which a disc core member made of a similar permeable material is mounted for rotation.
- disc core has wound thereon a coil: which has a voltage induced therein in accordance with the flux induced in the radial bars and the relative position of the bars and the coil.
- the relative position at which a null is secured is indicative of the direction of arrival of the electromagnetic field.
- high-frequency high-permeability materials and magnetic antenna elements are to be understood to mean materials which have high-resistivity and permeability, and magneticantennas constructed with such materials.
- Such materials are those known, for example, as ferrites or such compositions as dust iron. formed into suitable solid shape by a high-resistivity binder.
- conducting-surface or the like is hereby limited. to mean non-magnetic conducting material surfaces which have low-permeability, for e x' an antenna. system in accord magnetic flux in the bar by means of, for exon the electrical performance of the a mounted in a.
- fragmentary Fig. 3 is a sectional view along the line 3-3 of Fig. 2;
- Fig. 4 is a sectional view along the line 4-4 of Fig. 2.
- a conducting surface 8 having secured in an opening therein a magnetic rod 9 which has a coil 10 wound thereon.
- the rod 9 has a high-permeability and is non-conducting and may have a dielectric constant greater than unity, if de sired.
- One ferrite material which has given satisfactory results is that known in the trade as Stackpole Ceramag 4.
- the antenna may be utilized for transmission or reception by connecting the terminals of the coil 10 to appropriate circuits in a conventional manner.
- Fig. 2 is shown an aircraft surface 11, which has embedded therein three bars 12 which are made of a high-permeability high-resistivity material or iron dust held together with a suitable non-conducting binder.
- the bars 12 are long in comparison to their cross-sectional dimensions and are retained in the recesses in the surface 11 by being embedded in low loss plastic 13 or like material which may be molded and hardened.
- the disc 15 has a coil 16 wound thereon which may be center-tapped, if desired. Connections to the coil 16 are made by means of slip rings as will be hereinafter described.
- the rods 12 may have shaped pole shoes which are adjusted to reduce a sextantal error in the null voltage position of the coil 16 resulting from the three rod arrangement.
- Fig. 3 the bar 12 is shown embedded in plastic 13 thus forming a substantially continuous surface between the portions of the aircraft surface 11 adjacent the recess. if desired, an exactly flush surface construction could be used.
- Fig. 4 shows the core 15 rotatably mounted in a hearing 17 coaxial with the opening 14.
- the end and center terminals of the coil 16 are connected to slip rings 18 which are contacted by brushes 19.
- the coil and core assembly may be rotated by manual or power means, not shown, depending upon the particular system into which the antenna is incorporated.
- the opening 14 may be closed by a suitable cover plate mounted in a recess, if desired.
- eachbar opposes a virtual or phantom bar which is the resultant of the other two, and where the pole faces each embrace only about at most of the circumference of the core, while the coil is widely distributed over the core, the flux paths about the coil have always essentially the same reluctance, thus minimizing inductance variations.
- the large air gap between adjacent pole faces of the bars as compared to the gap between the pole faces and the core, reduces shunting to a negligible figure. For a given effective antenna height this structure is extremely li ht.
- the operation of the magnetic antenna system of the present invention may be qualitatively explained by analogy with the well known electric antennas.
- conductive antennas such as the halfwave dipole, represent a conductivity discontinuity and the performance of such antennas is markedly affected by the proximity of other conductors such as the ground plane.
- the magnetic antenna represents a magnetic discontinuity of high permeability and in accordance with the present teaching the performance thereof is not seri- 22 which may be flushously impaired by the proximity of the conducting ground plane.
- the antenna system of the present invention picks up radio frequency signals with an effective height equivalent to that of many prior art protruding antennas.
- the effective height of the antenna increases with physical dimensions for dimensions much smaller than a wavelength and in a particular application it will be understood that the maximum physical size and weight of an antenna will be fixed by other considerations.
- a satisfactory di rection finder antenna similar to that of Fig. 2 for the frequency range of -1750 kilocycles per second had the bars 12 each of length 14 inches, and 0.75 inch in diameter, thereby providing a physical arrangement well adapted for mounting in the wing of an aircraft.
- The'bars 12- may be designed as magnetic antenna elements in a manner sim ilar to that described in an article entitled, The Magnetic Antenna by Leigh Page, published in Physical Review, June 1946.
- the bars 12 should be as long as is practicable and the transverse dimensions suit: ably chosen.
- a direction finding magnetic. antenna system for electromagnetic radiation comprising, three rods formed of particles of magnetic material embedded in a high-resistivity binder and having lengths which are several 'tirnes longer than their cross-sectional dimensions, means disposing said rods radially in the field of said radiation, a core of high-frequency highpermeability material rotatably mounted centrally of said rods, a coil on said core, and means for obtaining a signal from the induced voltages in said coil, the air gaps said rods being substantially greater than the air gaps'b'e tween said rods and said core, whereby shunting of flux and inductance'variations are minimized.
- a direction finding magnetic antenna system tromagnetic radiation comprising,
- a magnetic antenna system comprising, a plura'lity of between the adjacent ends of three rods of highfl frequency high-permeability material disposed essentially.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Astronomy & Astrophysics (AREA)
- Aviation & Aerospace Engineering (AREA)
- General Physics & Mathematics (AREA)
- Remote Sensing (AREA)
- Details Of Aerials (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Waveguide Aerials (AREA)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US264717A US2740113A (en) | 1952-01-03 | 1952-01-03 | Magnetic antenna systems |
GB4981/52A GB719326A (en) | 1952-01-03 | 1952-02-26 | Improvements in or relating to the securing of blading to turbine wheels and other high speed rotary members |
GB31778/52A GB719526A (en) | 1952-01-03 | 1952-12-15 | Magnetic antenna systems |
FR1075235D FR1075235A (fr) | 1952-01-03 | 1952-12-23 | Systèmes d'antennes magnétiques |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US264717A US2740113A (en) | 1952-01-03 | 1952-01-03 | Magnetic antenna systems |
Publications (1)
Publication Number | Publication Date |
---|---|
US2740113A true US2740113A (en) | 1956-03-27 |
Family
ID=23007304
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US264717A Expired - Lifetime US2740113A (en) | 1952-01-03 | 1952-01-03 | Magnetic antenna systems |
Country Status (3)
Country | Link |
---|---|
US (1) | US2740113A (fr) |
FR (1) | FR1075235A (fr) |
GB (2) | GB719326A (fr) |
Cited By (32)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2804617A (en) * | 1954-06-02 | 1957-08-27 | Wladimir J Polydoroff | Antenna systems |
US2870442A (en) * | 1956-03-26 | 1959-01-20 | Wladimir J Polydoroff | Ferromagnetic antenna systems |
US2895129A (en) * | 1956-01-30 | 1959-07-14 | Gen Bronze Corp | Mobile radio antenna |
US2915752A (en) * | 1953-12-29 | 1959-12-01 | Raytheon Co | Directional antenna |
US2948888A (en) * | 1957-03-15 | 1960-08-09 | Avco Mfg Corp | Magnetic energy transmitter for a remote control system for a television receiver |
US3012246A (en) * | 1957-08-30 | 1961-12-05 | Internat Res & Dev Corp | Antenna unit |
US3020547A (en) * | 1956-08-02 | 1962-02-06 | Gasaccumulator Svenska Ab | Arrangement for radio direction finding |
US3354459A (en) * | 1965-08-05 | 1967-11-21 | Devenco Inc | Tri-orthogonal antenna system with variable effective axis |
US3409891A (en) * | 1965-09-20 | 1968-11-05 | Rosemount Eng Co Ltd | Surface antenna |
EP0183521A1 (fr) * | 1984-11-27 | 1986-06-04 | Toyota Jidosha Kabushiki Kaisha | Système d'antenne pour véhicule automobile |
US4707701A (en) * | 1984-10-26 | 1987-11-17 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4717922A (en) * | 1984-11-06 | 1988-01-05 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4717921A (en) * | 1984-11-15 | 1988-01-05 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4723127A (en) * | 1984-12-12 | 1988-02-02 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4746926A (en) * | 1986-09-29 | 1988-05-24 | The United States Of America As Represented By The Secretary Of The Army | Phase scan antenna |
US4754284A (en) * | 1984-11-15 | 1988-06-28 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4789866A (en) * | 1984-11-08 | 1988-12-06 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4792807A (en) * | 1985-03-27 | 1988-12-20 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4794397A (en) * | 1984-10-13 | 1988-12-27 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna |
US4804966A (en) * | 1984-10-29 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4804968A (en) * | 1985-08-09 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4804967A (en) * | 1985-10-29 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4806942A (en) * | 1985-06-10 | 1989-02-21 | Toyota Jidosha Kabushiki Kaisha | Automobile TV antenna system |
US4811024A (en) * | 1984-10-17 | 1989-03-07 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna |
US4816837A (en) * | 1985-08-01 | 1989-03-28 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4819001A (en) * | 1984-11-26 | 1989-04-04 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4821042A (en) * | 1985-06-28 | 1989-04-11 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4845505A (en) * | 1987-02-13 | 1989-07-04 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system for diversity reception |
US5734353A (en) * | 1995-08-14 | 1998-03-31 | Vortekx P.C. | Contrawound toroidal helical antenna |
US5864323A (en) * | 1995-12-22 | 1999-01-26 | Texas Instruments Incorporated | Ring antennas for resonant circuits |
US6249258B1 (en) * | 1995-09-15 | 2001-06-19 | Aeg Identifikationssysteme | Transponder arrangement |
US6320550B1 (en) | 1998-04-06 | 2001-11-20 | Vortekx, Inc. | Contrawound helical antenna |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1024198B (de) * | 1955-02-03 | 1958-02-13 | Maschf Augsburg Nuernberg Ag | Trommellaeufer fuer axial beaufschlagte Kreiselradmaschinen und Verfahren zu dessen Herstellung |
US3047936A (en) * | 1959-03-11 | 1962-08-07 | Curtiss Wright Corp | Gas turbine rotor |
EP1099275A1 (fr) * | 1998-07-22 | 2001-05-16 | Poynting Innovations (Prpprietary) Limited | Antenne conformee |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1842347A (en) * | 1928-02-23 | 1932-01-19 | Eaton Radio Instr Corp | Method and apparatus for determining direction |
US1844859A (en) * | 1926-04-03 | 1932-02-09 | Levy Lucien | Magnetic and radioelectric goniometry |
US2242200A (en) * | 1938-12-01 | 1941-05-13 | Bell Aircraft Corp | Airplane structure |
US2266454A (en) * | 1937-07-09 | 1941-12-16 | Int Standard Electric Corp | Wireless direction finding system |
FR874946A (fr) * | 1940-07-26 | 1942-08-31 | Telefunken Gmbh | Système d'antenne radiogoniométrique |
DE726143C (de) * | 1938-11-15 | 1942-10-07 | Telefunken Gmbh | Peilantennensystem |
US2493779A (en) * | 1945-02-05 | 1950-01-10 | Jacob H Rubenstein | Magnetometer |
US2510698A (en) * | 1946-01-28 | 1950-06-06 | Johnson William Arthur | Radio aerial, particularly for aircraft and other vehicles |
US2581348A (en) * | 1948-04-10 | 1952-01-08 | Int Standard Electric Corp | Antenna |
-
1952
- 1952-01-03 US US264717A patent/US2740113A/en not_active Expired - Lifetime
- 1952-02-26 GB GB4981/52A patent/GB719326A/en not_active Expired
- 1952-12-15 GB GB31778/52A patent/GB719526A/en not_active Expired
- 1952-12-23 FR FR1075235D patent/FR1075235A/fr not_active Expired
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1844859A (en) * | 1926-04-03 | 1932-02-09 | Levy Lucien | Magnetic and radioelectric goniometry |
US1842347A (en) * | 1928-02-23 | 1932-01-19 | Eaton Radio Instr Corp | Method and apparatus for determining direction |
US2266454A (en) * | 1937-07-09 | 1941-12-16 | Int Standard Electric Corp | Wireless direction finding system |
DE726143C (de) * | 1938-11-15 | 1942-10-07 | Telefunken Gmbh | Peilantennensystem |
US2242200A (en) * | 1938-12-01 | 1941-05-13 | Bell Aircraft Corp | Airplane structure |
FR874946A (fr) * | 1940-07-26 | 1942-08-31 | Telefunken Gmbh | Système d'antenne radiogoniométrique |
US2493779A (en) * | 1945-02-05 | 1950-01-10 | Jacob H Rubenstein | Magnetometer |
US2510698A (en) * | 1946-01-28 | 1950-06-06 | Johnson William Arthur | Radio aerial, particularly for aircraft and other vehicles |
US2581348A (en) * | 1948-04-10 | 1952-01-08 | Int Standard Electric Corp | Antenna |
Cited By (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2915752A (en) * | 1953-12-29 | 1959-12-01 | Raytheon Co | Directional antenna |
US2804617A (en) * | 1954-06-02 | 1957-08-27 | Wladimir J Polydoroff | Antenna systems |
US2895129A (en) * | 1956-01-30 | 1959-07-14 | Gen Bronze Corp | Mobile radio antenna |
US2870442A (en) * | 1956-03-26 | 1959-01-20 | Wladimir J Polydoroff | Ferromagnetic antenna systems |
US3020547A (en) * | 1956-08-02 | 1962-02-06 | Gasaccumulator Svenska Ab | Arrangement for radio direction finding |
US2948888A (en) * | 1957-03-15 | 1960-08-09 | Avco Mfg Corp | Magnetic energy transmitter for a remote control system for a television receiver |
US3012246A (en) * | 1957-08-30 | 1961-12-05 | Internat Res & Dev Corp | Antenna unit |
US3354459A (en) * | 1965-08-05 | 1967-11-21 | Devenco Inc | Tri-orthogonal antenna system with variable effective axis |
US3409891A (en) * | 1965-09-20 | 1968-11-05 | Rosemount Eng Co Ltd | Surface antenna |
US4794397A (en) * | 1984-10-13 | 1988-12-27 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna |
US4811024A (en) * | 1984-10-17 | 1989-03-07 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna |
US4707701A (en) * | 1984-10-26 | 1987-11-17 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4804966A (en) * | 1984-10-29 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4717922A (en) * | 1984-11-06 | 1988-01-05 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4789866A (en) * | 1984-11-08 | 1988-12-06 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4717921A (en) * | 1984-11-15 | 1988-01-05 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4754284A (en) * | 1984-11-15 | 1988-06-28 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4819001A (en) * | 1984-11-26 | 1989-04-04 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4717920A (en) * | 1984-11-27 | 1988-01-05 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
EP0183521A1 (fr) * | 1984-11-27 | 1986-06-04 | Toyota Jidosha Kabushiki Kaisha | Système d'antenne pour véhicule automobile |
US4723127A (en) * | 1984-12-12 | 1988-02-02 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4792807A (en) * | 1985-03-27 | 1988-12-20 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4806942A (en) * | 1985-06-10 | 1989-02-21 | Toyota Jidosha Kabushiki Kaisha | Automobile TV antenna system |
US4821042A (en) * | 1985-06-28 | 1989-04-11 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4816837A (en) * | 1985-08-01 | 1989-03-28 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system |
US4804968A (en) * | 1985-08-09 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4804967A (en) * | 1985-10-29 | 1989-02-14 | Toyota Jidosha Kabushiki Kaisha | Vehicle antenna system |
US4746926A (en) * | 1986-09-29 | 1988-05-24 | The United States Of America As Represented By The Secretary Of The Army | Phase scan antenna |
US4845505A (en) * | 1987-02-13 | 1989-07-04 | Toyota Jidosha Kabushiki Kaisha | Automobile antenna system for diversity reception |
US5734353A (en) * | 1995-08-14 | 1998-03-31 | Vortekx P.C. | Contrawound toroidal helical antenna |
US5952978A (en) * | 1995-08-14 | 1999-09-14 | Vortekx, Inc. | Contrawound toroidal antenna |
US6249258B1 (en) * | 1995-09-15 | 2001-06-19 | Aeg Identifikationssysteme | Transponder arrangement |
US5864323A (en) * | 1995-12-22 | 1999-01-26 | Texas Instruments Incorporated | Ring antennas for resonant circuits |
US6320550B1 (en) | 1998-04-06 | 2001-11-20 | Vortekx, Inc. | Contrawound helical antenna |
Also Published As
Publication number | Publication date |
---|---|
GB719526A (en) | 1954-12-01 |
FR1075235A (fr) | 1954-10-14 |
GB719326A (en) | 1954-12-01 |
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