US3132342A - Antenna system using parasitic elements and two driven elements at 90 deg. angle fed180 deg. out of phase - Google Patents

Antenna system using parasitic elements and two driven elements at 90 deg. angle fed180 deg. out of phase Download PDF

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US3132342A
US3132342A US20947862A US3132342A US 3132342 A US3132342 A US 3132342A US 20947862 A US20947862 A US 20947862A US 3132342 A US3132342 A US 3132342A
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elements
antenna
monopole
satellite
antenna elements
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Roland R Ford
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Roland R Ford
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04Resonant antennas
    • H01Q9/44Resonant antennas with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions

Description

3,132,342 TWO DR HASE May 5, 1964 R. R. FORD ANTENNA SYSTEM USING PARASITIC ELEMENTS AND IVEN ELEMENTS AT 90 ANGLE FED 180 OUT OF P 1962 2 Sheets-Sheet 1 Filed July 12,

g LINEAR FEED l (HORIZONTAL DIPOLE) CIRCULAR FEED PRIOR ART R A R O R P INVENTOR ROLAND R. FORD May 5, 1964 R. R. FORD 3,13 4

ANTENNA SYSTEM USING PARASITIC ELEMENTS AND TWO DRIVEN ELEMENTS AT 90 ANGLE FED 180 OUT OF PHASE Filed July 12, 1962 2 Sheets-Sheet 2 INVENTOR ROLAND R. FORD {Ma/Q4 ATTORNEYS -vi de an antenna system ferred embodiment of the ments, each of which is approximately one-quarter wave- I ANTENNA SYSTEM'USING'PARASITIC ELENENTS AND TWO DRIVEN ELEMENTS AT 90 ANGLE FED 180 OUT OF PHASE Roland R. Ford, District Heights, Md., assignor to the United States of America as represented by the Administrator of the National Aeronautics and Space Administration 7 Filed July 12, 1962, Ser. No. 209,478 r I v 7 Claims. (Cl. 343-705) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured I and used by or for the Government of the United States of America :for governmental purposes without the payment of any royalties thereon or therefor. .The present invention relates generally to improved antenna system with respect to the antenna system of the ground'station. This problem arises because antennas generally have directional radiation characteristics and be cause the orientation of the satellite with respect to Earth is either unknown or continuously changing.

A partial solution to this problem has been theme of monopole antenna elements attached to the, outer surface of the satellite. FIG. 1 shows an antenna system which has been'used on previously launched satellites. It con; sists of four monopole .tached' ina common plane to the outer surface of the metallic satellite; The four monopole antenna elements are. spaced 90 apart physically, and fed in phase quadratureelectrically. The radiation pattern of this antenna system has four lobes with appreciable nulls in-the plane :of the four monopole antenna elements. In future satellite'applications, it is important that these nulls be reduced as much as possible. r

v The general purpose of the present invention is to profor general use and for use on satellites, which embraces all the advantages of similarly employed antennas and which has lesser antenna pattern nulls than previously used antenna systems. In aprefour monopole ele:

invention,

length of the transmitting frequency in physical length, are-insulatedly attached to the outer surface of a metallic satellite. The four monopole elements are located in a common plane and are spaced 90f apart physically.- Two electrically. The remaining which are are fed 180 out of phase two monopole elements are parasitic elements I interconnected to a load impedance for single frequency operation.

Dual frequency operation may be achieved by 1 ed S ates Pa n 10 f I tenna systems, and more particularly to antenna systems antenna elements insulatedly atadjacent monopole elements are active elements which Patented May 5,1954

with a view to providing an optimum antenna system for the NASA AtmosphericStructure Satellite (8-6). The satellite is a pressurized 35-inch sphere of stainless steel, which has a spinning motion in orbit; its tracking frequency is 136 mc. linearly polarized, and its telemetry' and command frequencies are respectively. .l36 and 120 mc. cross-linearly polarized. The antenna investigations were conducted on a scaled down model (6.5 inches in diameter, or about 125.3). of the satellite, with a proportionately increased;frequency of 720 mc. I v 7 An investigation was conducted on an antenna system mounted on a metallic satellite like the one shown in FIG. 1. The four quarter wavelength monopole elements were 'mounted on the equatorv (a' circumference) of the model. The four monopole elements were spaced 90? apart physically, and phased 90 apart electrically. Equatorial plane patterns were measured at 720 mc. for both linear feed (horizontal dipole) and circular feed. Linear feed and circular feed mean that the monopole elements are fed so thatthe electromagnetic waves emitted by them are linearly polarized and circularly polarized, respectively. These patterns are shown in FIG. 2. The dashed line pattern was measured with linear feed. 'The maxi,- mum null depth. of, this pattern, comparedto the maxi mum pattern lobe, was 18v db. The solid line patternwas measured with a circular feed source, and showed a'maximum null depth of 14.5 db.. i v Another investigation was conducted on an antenna systern mounted on the model simulating a metallic satellite. In this investigation four quarter wavelength monopole elements were mounted on the equator of the model and spaced 90 apart physically.- 'Two adjacent monopole elements were fed 180 out of phase. with a 720 mc. source- The other ",two monopole elements were connected to a SO-ohm floating load resistor. Equatorial planepatterns were measured for both linear and circular feeds. The maximum null depth for the linear feed was 6 db and the maximum null depth for thecircular'feed was 6.3 db. vA polar plane pattern was measured for a circular feed and was found to have only a 4 db null depth. This pattern was confirmed by recording a hori} zontal dipolepattern and a vertical dipole pattern. The vector sum of the horizontal and vertical components gave a pattern with less than 3 db. nulls when compared to the antenna system.

replacing the load impedance with either a transmitter or receiver operating at a second frequency. In this case,

a each fed or active pair of monopole elements will use the 'c elements.

other pair of monopole elements as parasi six monopole In another embodimentof the invention,

elements are insulatedly attached to the outer surface of i pair are adjacent to each other and are fed 180 out of phase. Ateach frequency, two monopole elements are fed, and the other four monopole elements are parasitic elements.

The invention is th A further object of the invention-is toprovide a multifrequency antenna system. f A still further objectof the invention is to. improve the pmnidirectional coverage of an antenna system for satellite application. i a I Other'objects and a fuller understanding of the inven: tion may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which: a i j FIG. 1 shows a prior art antenna mounted on afnetallic satellite, in which oneembodiment of this invention incorporated; I j

FIG. 2 shows equatorial plane antenna patterns for a prior art antenna system incorporated in the prior art an tenna shown in FIG. 1;

result of investigations performed FIG. 3 is a cross-sectionalview of FIG 1 incorporating one embodiment of this invention; i j

FIG. 4 shows six monopole antenna elements insulatedly attached ot the metallic outer surface of a satellite in which another embodiment of this invention is incorporated; and

FIGS. a, 5 b, and 5c shows three mutually perpendicular cross-sectional views of FIG. 4 as indicated by section lines.5a-5a, 5b 5b, and 5c5c.

With reference to FIG..3 of the drawings, one embodiment of the invention is illustrated as being incorporated in a metallic spherical satellite indicated generally by the physical length. Monopole antenna elements 11 and 14 are fed by transmitter 15 through a coaxial cable 16.

' The outer conductor of cable 16 is connected to the metallic shell of satellite 10 and the inner conductor of cable' 16 is connected to antenna elements 11 and 14. Transmitter 15 feeds cable 16 at a point one quarter .of a wavelength from antenna element 11 and three quarters of a wavelength from antenna element 14. Consequently, the signals fed to antenna elements 11 and 14 are 180 out of phase. That is, if antenna element 11 is fed at some phase angle 9 then antenna element 14 is fed at a phase angle of 0-180".

Antenna elements 12 and 13 are'connected to a floating resistor 17 through a coaxial cable 18. The outer conductor of cable 18 is connected. to the shell of satellite 10, and the inner conductor of cable 18 is connected to antenna elements 12 and 13. Resistor 17 isconnected to i of the plane containing monopole antenna elements 21, 22, 23 and 24; FIG. 5b is a cross-sectional view of the plane containing monopole antenna elements 22, 24, 25 and 26; and FIG. 50 is a cross-sectional view of the plane containing monopole antenna elements 21, 23, 25 and 26. As illustrated in FIG. 5a, four monopole antenna ele-' ments (21, 22, 23 and 24) are insulatedly attached, in the' same plane 90 apart, to the outer surface of satellite 20. Monopole antenna elements 21 and 22 are fed by a transmitter 27 through a coaxial cable 28. The outer conductor of cable 28 is connected to themetallic shell of satellite and the inner conductor of cable 28 is connected to antenna elements 21 and 22. The transmitter 27 feeds cable 28 at a point one quarter of a wavelength of the transmitter operating frequency from antenna 22 and three quarters of a Wavelength'of this operating frequency from antenna 21. Antenna elements 21 and 22 each have a physical length equal to one quarter of a v wavelength of the operating frequency of transmitter 27.

cable 18 at a point three'quarters of a wavelength from differences of the two distances be zero or some multiple of one half .of a wavelength. The floating resistor is connected to cable 18 to simulate equipment (transmitter or receiver) which might be connected to the antenna elements. The value of resistor 17 is not critical. In the operation of the embodiment of the invention 7 shown inFIG. 3, signals applied to cable 16 by transmitter 15 are applied to antenna elements 11 and 14. .Because of the relative lengths of cable 16 fromtransmitter 15 to antenna elements 11 and 14, the signals applied to antenna elements 11 and 14 are 180 out of phase. Antenna elements 12 and 13 are parasitic and improve the omnidirectional coverage of antenna elements 11 and 14. It should be noted that dual frequency operation may berealized by 'the embodiment of this invention shown by FIG. 3, if the resistor 17 is replaced by a transmitter or receiver operating at a second frequency. If this be true, each pair of monopole elements will be fed or active at one frequency and will be parasitic at the other fre-. quency. For this dual frequency operation monopole elements '12 and 13 should be one quarter of a Wavelength of the second frequency, in length, and monopole elements 11 and 14 should be one quarter-of a wavelength of the operating frequency of transmitter 15, in length.

With reference to FIGS. 4 and 5 of the drawings, another embodiment of the invention is illustrated wherein the spherical satellite is indicated generally by the 'refer ence character 20. FIG. 4 shows the metallic spherical to the surface of the satellite and electrically insulated from the satellite with asuitable insulating material. FIG. 5 shows'three mutuallyperpendicular cross-sectional views of FIG. 4; FIG. 5a is a cross-sectional view transmitter 31 through a coaxial cable As illustrated in FIG. 5b, four monopole antenna elements. (24, 25, 22 and 26) are insulatedly attached,'in the same plane apart, to the outer surface of satellite 20. Monopole antennaQelements 24 and 25 are fed bya transmitter 29 through a coaxial cable 39. The outer'conductor of cable '39 is connected to the metallic shell of the satellite 20, and the inner conductor of cable 30 is connected to antenna elements 24 and 25. The transmitter 29 feeds cable 30 at a of the transmitter operating frequency from antenna element 25 and three 'quarters of a wavelength of this frequency from antenna element 24. i Antenna elements 24 and 25 each have a physical length equal to one quarter of a wavelength of the operating frequency of transmitter'29. i

As illustrated in FIG. 50, four monopole antenna elements (21, 25, 23, and 26) are insulatedly attached, in the same plane 90 apart, to the outer surface of satellite 20. Monopole antenna elements 23 and 26 are fed by a 32. The outer conductor of cable 32 is connected to the metallic shell of satellite 20, and the inner conductor of cable '32 is connected to antenna elements 23 and 26. The transmitter 31 feeds cable 32 at a point one quarter of a wavelength 'of the transmitter operating frequency from antenna element 26, and three quarters of a wavelength of this frequency from antenna element 23. Antenna elements 23 and 26 each have a physical length equal to one quarter of'a wavelength of the operating frequency of transmitter 31. a

In the operation or the embodiment of the invention shown in FIGS. 5a, 5b, and 5c, signals applied to cables 28, 30 and 32 by transmitters 27, 29 and 31 are respectively applied to antenna element pairs 21, 22; 24, 25; and 23, 26. The antenna elements of each pair are fed out of phase by their respective transmitters. Transmitter 27,'at its operating frequency, feeds antenna element pair 21, 22, and antenna element pairs 24,25 and 23, 26 are, parasitic elements at that frequency. Transmitter 29, at its operating frequency, feeds antenna element pair 24, 25 and antenna element pairs 21, 22 and 24, 25 are parasitic elements at that frequency. Transmitter 31, at its operating frequency, feeds antenna element pair 23, 26, and antenna element pairs 21,22 and 24, 25 are parasitic elements at that frequency; I

The parasitic actions of the three antenna, element pairs are optimum when the three operating frequencies are fairly close to each' other, preferably within 20%,.

ment of FIG. 3; in addition, it can radiate at three independent frequencies simultaneously. If necessary, tuned circuits can be used to keep each pair of fed antenna elepoint one quarter of a wavelength units feeding each pair of more uniformly Within the satellite.

Obviously numerous modifications or variations of the present invention are possible in light of the above teachings. For example,

transmitter. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein. What is claimed is: a 1. An antenna system for use on an unoriented spherical metallic satellite comprising: four monopole antenna elements each having a physical length equal to one 7 quarter of a wavelength of the operating frequency of the antenna system; means for insula'tedly attaching the said four monopole antenna elements to the outer surface of the satellite in a common plane 90 apart; means for applying, at the operating frequency, signals to be. radiated 180 out of phase to anadjacent two of said four connected to the other two of said four monopole antenna elements to form an antenna element pair whereby the omnidirectional coverage of the antenna system is improved; i V K y 12. A dual frequency antenna system for use on an unf oriented'spherical metallic satellite comprising: four monopole antenna elements two of which have a physical length equal to one quarter of a wavelength of one of said dual frequencies and the other two of which have a the othenof said dual frequencies; means for insulatedly attaching said four monopole antenna elements to the outer surface of the satellite in a common plane 90 vapart'with the monopole 'antenna elementshaving equal lengths adjacent to each otherrmeans for applying, at one of said dual frequencies, signals to be radiated 180 out of phase to the two monopole antenna elements whose lengths are equal to one quarter of a wavelength of said one ofsaid dual frequenciesyand means for applying, 'at the other of said dual frequencies, signals to be radi- Iated .180 out of phase to the two monopole antenna ele ment's whose lengths are equal to one quarter of a wavea length of said other of said dual frequencies whereby two,

monopoleantenna elements are active and two are parasitic for each of said dual frequencies.

1' 3. A multifrequency antenna system foruse on-an un- Yoriented spherical metallic satellite comprising; six monopole antenna elements, twoof which have a' physical fjquenc'y, two of which have a physical length equal to one of which have a physical length equal to one quarter of a attaching said six'monopole antenna elements at points "equally spaced around the outer surface of the satellite -with the monopole antenna elements having equal lengths adjacent to eachother; frequency, signals to be radiated 180. out of phase to the 'tion where balanced weight is importantthe circuit antenna elements can be spaced a receivercan be substituted for any monopole a ntenna elements; and a floating resistor means physical length equal to one quarter of a Wavelength of =length equal to one quarter of a wavelength of a first fremeans for applying, at said'tirst to one quarter of a wavelength of said first frequency; means for applying, at said be radiated 180 out of anterma elements whose lengths are equal to one quarter of a wavelength of said second frequency; and means for applying, at said third frequency, signals to be radiated 180 to thetwo monopole antenna elements whose lengths are equalto one quarter of a wavelength of said third frequency whereby two monopole antenna elements are active and four are parasitic for each of said first, second, and third frequencies.

4. An antenna system for use on an unoriented satellite comprising: fourmonopole antenna elements equally spaced around and mounted the outer surface of the satellite; means for applying signals to be radiated 180 monopole antenna elements, whereby the other adjacent two monopole antenna elements form a parasitic antenna element pair which improves the omnidirectional coverage of the antennasystem.

6. A multifrequency antenna system for'use on an unoriented satellite comprising:

elements attached. at diiferent points to the outer surface of the satellite; means for applying separate different frequency signals to be radiated elements of the six monopole antenna elements'whereby three different frequencysignals are radiated simultan e-' ouslyeach signal beingradiated by an active antenna element pair and" by two parasitic antenna elementpairs to improve the omnidirectional coverage of, the antenna 7. An antenna system for radiating signals at three diiferent frequencies simultaneously, comprising: three pairs of monopole antenna elements formedby adjacent monopole antenna elements with the two antenna elementsof each pair being approximately equal to one quarter: of a wavelengthof a second frequency, and two twol monopole antenna elements whose lengths are equal quarter of a wavelength of their operating frequency in length; means for applying different frequency signals to each pair of antenna elements and for applying'the signals to the two monopole antenna elements of each" I out of phase whereby each signal is radiated by an active antennaxelement pair and by two parasitic antenna element pairs to improve the, omnidirectional ,coverage of the antenna system. 1 a 3 wavelength of a third frequency; means for insulatedly References Cited in the file of this patent V v {UNITED STATES PATENTS 7 2,224,898 Carter m-. Dec..17,f1940 second frequency, signals to .0 phase to the two monopole in a common plane, on j p out of phase to an adjacent two of the four monopole antenna elements; and means six monopole antenna to each of three antenna element pairs formed by adjacent monopole antenna

Claims (1)

1. AN ANTENNA SYSTEM FOR USE ON AN UNORIENTED SPHERICAL METALLIC SATELLITE COMPRISING: FOUR MONOPOLE ANTENNA ELEMENTS EACH HAVING A PHYSICAL LENGTH EQUAL TO ONE QUARTER OF A WAVELENGTH OF THE OPERATING FREQUENCY OF THE ANTENNA SYSTEM; MEANS FOR INSULATEDLY ATTACHING THE SAID FOUR MONOPOLE ANTENNA ELEMENTS TO THE OUTER SURFACE OF THE SATELLITE IN A COMMON PLANE 90* APART; MEANS FOR APPLYING, AT THE OPERATING FREQUENCY, SIGNALS TO BE RADIATED 180* OUT OF PHASE TO AN ADJACENT TWO OF SAID FOUR MONOPOLE ANTENNA ELEMENTS; AND A FLOATING RESISTOR MEANS CONNECTED TO THE OTHER TWO OF SAID FOUR MONOPOLE ANTENNA ELEMENTS TO FORM AN ANTENNA ELEMENT PAIR WHEREBY THE OMNIDIRECTIONAL COVERAGE OF THE ANTENNA SYSTEM IS IMPROVED.
US3132342A 1962-07-12 1962-07-12 Antenna system using parasitic elements and two driven elements at 90 deg. angle fed180 deg. out of phase Expired - Lifetime US3132342A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263229A (en) * 1961-09-18 1966-07-26 Csf Radio transmission relay stations
US3464016A (en) * 1966-01-13 1969-08-26 Nasa Demodulation system
US3662260A (en) * 1971-02-12 1972-05-09 Us Navy Electric field measuring instrument with probe for sensing three orthogonal components

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2224898A (en) * 1938-02-05 1940-12-17 Rca Corp Wide band short wave antenna
US2480182A (en) * 1945-09-19 1949-08-30 Us Sec War Antenna
US3063048A (en) * 1959-05-04 1962-11-06 Space General Corp Discovery and location system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2224898A (en) * 1938-02-05 1940-12-17 Rca Corp Wide band short wave antenna
US2480182A (en) * 1945-09-19 1949-08-30 Us Sec War Antenna
US3063048A (en) * 1959-05-04 1962-11-06 Space General Corp Discovery and location system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3263229A (en) * 1961-09-18 1966-07-26 Csf Radio transmission relay stations
US3464016A (en) * 1966-01-13 1969-08-26 Nasa Demodulation system
US3662260A (en) * 1971-02-12 1972-05-09 Us Navy Electric field measuring instrument with probe for sensing three orthogonal components

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