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Publication numberUS2432858 A
Publication typeGrant
Publication dateDec 16, 1947
Filing dateMar 31, 1943
Priority dateMar 31, 1943
Publication numberUS 2432858 A, US 2432858A, US-A-2432858, US2432858 A, US2432858A
InventorsGeorge H Brown
Original AssigneeRca Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Antenna system
US 2432858 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

Dec. 16, 1947. G. H. BROVVUN 2,432,858

ANTENNA SYSTEM Filed March 31, 1943 L 15 610 i DEV/(5: l I Inventor fik'o yz-filimwn Gmrncu Patented Dec. 16, 1947 UNITED STATES PATENT OFFICE 2,432,858 ANTENNA SYSTEM George H. Brown, Princeton, N. J-., 'assigno'r to Radio Corporation of America, acorporation of Delaware Application March 31, 1943, Serial No. 481,218

This invention relates to directive antennas and more particularly to antennas for providing alternately or sequentially overlapping directive patterns. Such antennas are generally applicable to radio aircraft locators, radio direction finders, object detectors and the like. Directive a'ntenna systems for ultra high frequencies frequently include a parabolic reflector with one or more radiator elements disposed at or near the focal point. The directive characteristic of the reflector is superimposed upon the field pattern of the radiator, providing substantially a single narrow pattern lobe. The axis of this lobe may be altered with respect to the axis of the reflec- -tor by moving the radiator system off center, or

necessary switching may be done at any convenient point in the feed system between the antenna and associated radio apparatus.

I A further object is to provide a structure of the above described type which is mechanically strong.

These and other objects will become apparent to those skilled in the art upon consideration of the following description with reference to the accompanying drawing, of which Fig. 1 is a perspective view of a radiator structure according "to the instant invention, Fig. 2 is a schematic diagram of thestructure of Fig. 1 and the associated transmission line circuits, and Fig. 3 is a schematic diagram of a portion of the system of Fig. 1. Similar reference characters indicate similar elements in the drawing.

Referring to Figs. 1 and 2 a coaxial transmis- "sion line I has its inner conductor connected to a radiator 3 substantially A; wave length long. Four radiator elements 5, I, 9 and i I are provided at the end of the outer conductor of the line I and extend radially therefrom along two lines at right angles to each other. Each of the elements 5, "1,9 and II comprise an inner conductor I3, which is connected to the outer conductor of the line I, and an outer conductor connected to the inner conductor at the outer end thereof by a plug I5. The outer conductors are made slightly shorter than the inner conductors to avoid contact 7 Claims. (Cl. 250-11 2 with the line I. Each of the radiator elements :5, I, 9 and-I I is approximately /4 wave length long.

Four coaxial lines I'I, I9, 2| and 23 surround the line I with their outer conductors connected to the outer conductor of the line I. The inner conductors of the lines I119, 2| and 23 are connected to the outer conductors of the radiator elements 5, 1, 9 and II respectively. The above described structure is positioned in a parabolic reflector, not shown. The focal point of the refiector lies approximately in the plane of the radiator elements 5, l, 9 and I I.

The lines I! and 2| are connected together at a point 25 which is one-half wavelength further from the radiator 5 than from the radiator' 9. so

odd number of half wavelengths. A transmission line 21 is connected to the point 25 and through a line section 29 one-half wavelength long to a line 3|. A switch 33 is connected across the section 29. The radiatorelements I and II are similarly connected to a junction point 35, aline 31 one-half w'ave section 39, a line 4i and a switch 43. The lines 3| and 4| are connected to a double throw switch '45 which is connected to the line I and through a line 4'! to a radio device, not shown,

A power division network may beprovidediin the connections between the line 41, the line I and the switch 45 if necessary to provide the proper ratio between the energizati'ons of the element 3 and the radiators 5, I, 9 and II. The total length of the line from the switch 45 to each of the elements 5, I, 9 and II is an odd number of quarter wavelengths. The switches 33, '43 and 45 may comprise rotatable variable capacitor means connected with resonant line sections or any other well known type of radio frequency circuit making and breaking devices. These switches may be mechanically ganged together for sequential operation by means of an electric motor-46 or the like.

The operation is as follows:

Assuming the antenna is to be used for transmission, the radiator 3 is constantly energized through lines I and 41. The switch '45 alternately connects the lines 3| and 4|, energizing the respective dipoles 5, 9, and I, II. When the line 3| is connected to the line 41, the open circuit presented at the lower end of the line 4| is transformed to a short circuit at the upper ends of the lines I9 and 23, efiectively grounding the outer conductors of the members I and II. The radiators and 9 are similarly grounded when the radiators I and II are energized. When the switch 33 is open the total length of the line between the switch 45 and the radiators 5 and 9 is one-half wave longer than when the switch 33 is closed. Thus by opening and closing the switch 33, the polarity of the dipole 5, 9 is reversed. Similarly when the lines 4| and 41 are connected together by the switch 45, operation of the switch 43 reverses the polarity of the dipole I, II.

The radiation pattern of the radiator 3, neglecting the effect of the reflector is approximately the shape of a torus with an inner radius of zero, maximum energy being radiated in all directions at right angles to the axis of the radiator 3,

The reflector 24 modifies the pattern by concentrating it in a forward direction to'form a relatively narrow hollow conical beam, with maximum radiation in all directions at apredetermined small angle to the axis. This pattern is substantially the same Whether one pair or the other of the elements 5, 1, 9 and II is grounded. When the switch 45 connects the line 3| and the switch 33 is closed, current flows in the radiator elements 5, 9, and 3 as indicated by the solid arrow in Fig. 2. The current through the elements 5 and 9 provides a toroidal radiation pattern with the axis of minimum radiation along the axis 5, 9. The reflector 24 modifies this pattern to form a single narrow lobe with its maximum intensity along the axis of the element l3.

At a point R in space ahead of and to theright of the array, the electric field vectorproduced by the element 3 is at right angles to the line between the antenna system and the point R, and is directed toward the center. The electric field vector produced by the dipole 5, 9 at point R is.

also'at right angles to the radial line CR, but extends in the opposite direction. Thus the fields tend to cancel.

At a point L to the left of the; axis of the radiator 3 the field vector produced by the radiator 3- is again at right angles to the line from the antenna to the point L and directed inwardly. The field vector at L produced by the dipole 5, 9 is also at right angles to the line CL but extends in the same direction as that produced by the element 3 at point L. Thus the total radiation pattern is asymmetrical, having a point of maximum intensity to the left of the axis of the radiator 3.

If the switch 33 (Fig, 2) is now opened, the

polarity of the dipole 5, 9 is reversed, producing field vectors at points L and R as indicated by the dash arrows. The fields are now added at the points to the right of the axis of the radiator 3 and subtracted at points to the left of radiator 3.

Thus by operating the switch 33 two overlapping radiation lobes are produced alternately by the elements 35 and 9. The axis of maximum radiation of two lobes lie in the plane defined by the elements 3, 5, and '9. The operation of the radiators 1 and II, when the switch 45 is thrown to connect lines 4! and 47 is identical with the above described operation. However, the axis of maximum radiation will now lie in the plane determined by the elements 3, l and l I. By operating the switches 33, 43 and 45 in the proper sequence, four overlapping directive patterns are provided pairs of said coplanar radiators.

2. An antenna system including two pairs of collinear radiators lying in a common plane, said pairs being disposed at an angle to each other, two concentric transmission lines each connected between the adjacent ends of the radiators of one of said pairs, two branch concentric lines each connected to one of said first mentioned lines at a point one-quarter wave length distant from the midpoint thereof, each of said branch lines including a one-half wave line section and means for selectively including and removing said section from the circuit thereof, a main transmission line, means for connecting said main transmission line selectively to one of said branch lines, and a radiator element disposed at right angles to the plane of said coplanar elements and connected to saidmain transmission line.

3; The invention as set forth in claim 2 wherein each of said two coplanar radiator elements comprises a concentric line section substantially onequarter wave length long and short-circuited at its outer end and with its inner conductor to the end of the outer conductor of said main transmission line.

4. The invention as set forth in claim 2 including a substantially parabolic reflector arranged with its focal plane lying substantiall in the plane of said coplanar radiators.

5. An antenna system comprising pairs of collinear radiator elements lying in a common plane, each of said elements comprising a coaxial line section substantially one-quarter wave length long with its inner conductor connected to a grounded supporting member at one end and to its outer conductor at the other end, two concentric lines each connected between the outer conductors of a respective pair of radiators, each of said concentric lines being substantially an odd number of half wave lengths long, two branch lines, one connected to each of said first mentioned lines at a point one-half wave length further from one radiator element than from the other radiator element of the respective pair, a fifth radiator element extending at right angles to two of said coplanar elements and connected to a main transmission line, and means for selectively connecting said branch lines to said main transmission line.

6. The invention as set forth in claim 5 wherein each of said branch lines includes means for changingthe length of the transmission path through said branch lines by one-half wave length.

Non-Patent Citations
Reference
1 *None
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2619596 *Nov 12, 1948Nov 25, 1952Kolster MurielMultiband antenna system
US2934286 *Jun 3, 1953Apr 26, 1960Kiernan Earl FRadar controlled missile
US3354459 *Aug 5, 1965Nov 21, 1967Devenco IncTri-orthogonal antenna system with variable effective axis
US3521286 *Apr 21, 1967Jul 21, 1970Gen Dynamics CorpOrthogonal array antenna system
US3618105 *Mar 6, 1970Nov 2, 1971Collins Radio CoOrthogonal dipole antennas
US3725943 *Oct 12, 1970Apr 3, 1973IttTurnstile antenna
US3789416 *Apr 20, 1972Jan 29, 1974IttShortened turnstile antenna
US4298874 *Oct 24, 1978Nov 3, 1981The Austin CompanyMethod and apparatus for tracking objects
US4314251 *Jul 30, 1979Feb 2, 1982The Austin CompanyRemote object position and orientation locater
US4328548 *Apr 4, 1980May 4, 1982The Austin CompanyLocator for source of electromagnetic radiation having unknown structure or orientation
US4346384 *Jun 30, 1980Aug 24, 1982The Austin CompanyRemote object position and orientation locator
US4633265 *Dec 24, 1984Dec 30, 1986Hazeltine CorporationLow frequency/high frequency omnidirectional antenna formed of plural dipoles extending from a common center
US4737794 *Dec 9, 1985Apr 12, 1988Mcdonnell Douglas CorporationMethod and apparatus for determining remote object orientation and position
US4742356 *Dec 9, 1985May 3, 1988Mcdonnell Douglas CorporationMethod and apparatus for determining remote object orientation and position
US5321412 *Jan 25, 1993Jun 14, 1994Sensormatic Electronics CorporationAntenna arrangement with reduced coupling between transmit antenna and receive antenna
US6538617Jan 3, 2002Mar 25, 2003Concorde Microsystems, Inc.Two-axis, single output magnetic field sensing antenna
US6879300Feb 7, 2001Apr 12, 2005Cms Partners, Inc.Wireless boundary proximity determining and animal containment system and method
US7142167Nov 4, 2004Nov 28, 2006Cms Partners, Inc.Wireless boundary proximity determining and animal containment
US7746284 *May 8, 2008Jun 29, 2010Electronics And Telecommunications Research InstituteCross dipole, cross dipole module, array antenna, and multiple input multiple output antenna
US8106846May 1, 2009Jan 31, 2012Applied Wireless Identifications Group, Inc.Compact circular polarized antenna
US8289218May 21, 2010Oct 16, 2012Venti Group, LLCCross-dipole antenna combination
US8325101Jul 21, 2010Dec 4, 2012Venti Group, LLCCross-dipole antenna configurations
US8427385Aug 3, 2009Apr 23, 2013Venti Group, LLCCross-dipole antenna
US8436780Aug 16, 2010May 7, 2013Q-Track CorporationPlanar loop antenna system
US8618998Jul 21, 2009Dec 31, 2013Applied Wireless Identifications Group, Inc.Compact circular polarized antenna with cavity for additional devices
US8624791Jun 5, 2013Jan 7, 2014Venti Group, LLCChokes for electrical cables
US8638270May 3, 2013Jan 28, 2014Venti Group, LLCCross-dipole antenna configurations
US8803755Jun 5, 2013Aug 12, 2014Venti Group, LLCLow passive intermodulation chokes for electrical cables
US8922440Jul 12, 2010Dec 30, 2014Q-Track CorporationSpace efficient magnetic antenna method
US9710576Dec 18, 2013Jul 18, 2017Venti Group, LLCCross-dipole antenna configurations
US20010030610 *Feb 7, 2001Oct 18, 2001Rochelle James M.Wireless boundary proximity determining and animal containment system and method
US20050093760 *Nov 4, 2004May 5, 2005Cms Partners, Inc.Wireless boundary proximity determining and animal containment
US20100277387 *Jul 12, 2010Nov 4, 2010Q-Track CorporationSpace Efficient Magnetic Antenna Method
US20110025569 *May 21, 2010Feb 3, 2011Venti Group, LLCCross-dipole antenna combination
US20110025573 *Aug 3, 2009Feb 3, 2011William Ernest PayneCross-dipole antenna
US20110068992 *Jul 21, 2010Mar 24, 2011Venti Group, LLCCross-dipole antenna configurations
Classifications
U.S. Classification343/791, 343/816, 343/725, 343/836, 342/374, 343/876, 343/797, 343/792
International ClassificationG01S19/44, G01S1/02
Cooperative ClassificationG01S1/02
European ClassificationG01S1/02