US3691562A

US3691562A - Omnidirectional beacon antenna

Info

Publication number: US3691562A
Application number: US103458A
Authority: US
Inventors: Ernest G Parker; Richard W Craine
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; ITT Inc
Priority date: 1971-01-04
Filing date: 1971-01-04
Publication date: 1972-09-12
Anticipated expiration: 1989-09-12

Abstract

A TACAN beacon antenna is disclosed having a central radiating element including eleven vertically stacked half wavelength tubular dipoles. A first dielectric cylinder carries the 15 cycle modulating parasitics including seven vertically aligned and spaced circumferentially parasitics coextensive with the central radiating element and a metallic disc below the central dipole. A second dielectric cylinder carries the 135 cycle modulating parasitics including nine circumferentially spaced groups of parasitic components, each group containing 10 vertically aligned and spaced parasitics and three vertically aligned and spaced parasitics intermediate adjacent groups. The radiating elements are fed by three concentric coaxial lines disposed coaxially of the vertical axis of the radiating elements and extending through the hollow drive shaft of a motor disposed coaxially of the vertical axis to drive the two modulating cylinders. The outer conductor of an inner coaxial line is the center conductor of an outer coaxial line such that the inner coaxial line feeds energy to the upper five radiating elements through metallic and dielectric impedance transformers the intermediate coaxial line feeds energy to the four intermediate radiating elements through metallic and dielectric impedance transformers and the outermost coaxial line feeds energy to the lower two radiating elements through dielectric impedance transformers.

Description

Unite 13 Sttes atent Parker et al.

[451 Sept. 12, 1972 [54] OMNIDIRECTIONAL BEACON ANTENNA [72] Inventors: Ernest G. Parker, Convent Station;

Richard W. Craine, Nutley, both of NJ.

[73] Assignee: International Telephone and Telegraph Corporation [22] Filed: Jan. 4, 1971 [21] AppLNo; 103,458

[52] US. Cl. ..343/761, 343/766, 343/792,

Primary Examiner-Eli Lieberman AuomeyC. Cornell Remsen, Jr., Walter J. Baum, Paul W. l-lemminger, Charles L. Johnson, Jr., Philip M. Bolton, Isidore Togut, Menotti J. Lombardi, Jr. and Edward Goldberg a F run a r soance POWER Div/MR [5 7] ABSTRACT A TACAN beacon antenna is disclosed having a central radiating element including eleven vertically stacked half wavelength tubular dipoles. A first dielectric cylinder carries the 15 cycle modulating parasitics including seven vertically aligned and spaced circumferentially parasitics coextensive with the central radiating element and a metallic disc below the central dipole. A second dielectric cylinder carries the 135 cycle modulating parasitics including nine circumferentially spaced groups of parasitic components, each group containing 10' vertically aligned and spaced parasitics and three vertically aligned and spaced parasitics intermediate adjacent groups. The radiating elements are fed by three concentric coaxial lines disposed coaxially of the vertical axis of the radiating elements and extending through the hollow drive shaft of a motor disposed coaxially of the vertical axis to drive the two modulating cylinders. The outer conductor of an inner coaxial line is the center conductor of an outer coaxial line such that the inner coaxial line feeds energy to the upper five radiating elements through metallic and dielectric impedance transformers the intermediate coaxial line feeds energy to the four intermediate radiating elements through metallic and dielectric impedance transformers and the outermost coaxial line feeds energy to the lower two radiating elements through dielectric impedance transformers. I

12'Claims, 4 Drawing Figures PAIEMEIJSEP 12 me 3691; 562

SHEEI 1 OF 4 RF MERCY $OURCE PHAS 5m PHA$ 64 INVENTORS ERNEST 6. PAR/(6R mlcuAga w. CRA/NE PATENTEU l 2 I973 3.691, 562

SHEET 3 BF 4 INVENTORS Ek/VEST G. PAR/(6R R/CHARb w. (RA/NE AGENT PMENFHJ E 2 I912 3.691.562

sum 0F 4 INVENTORS ERNEST G. PARKER R/cHAAw w. CRA/NE BACKGROUND OF THE INVENTION This invention relates to omnidirectional beacon antennas and more particularly to omnidirectional beacon antennas for use in producing a rotating multilobed radiation pattern having a fundamental modulation frequency and one or more additional harmonics of the fundamental frequency for use in radio navigation systems such as that mainly known as TACAN.

Omnidirectional beacon systems such as in TACAN have a high order of directional accuracy which is dependent upon the use of a directive antenna pattern rotated at a fundamental frequency and modulated by a harmonic of this fundamental frequency so as to produce a generally multilobed rotating directive radiation pattern. The antennas usually consist of a central omnidirectional radiator surrounded by radiation pattern modifying elements adapted to revolve around the central radiator. Due to the rotation of the multiplemodulation antenna pattern, a receiver located remotely from the transmitter receives energy which appears as an amplitude modulated wave having a fundamental modulation component and a modulation component at a harmonic frequency of the fundamental. Both fundamental and harmonic frequency reference signals are transmitted for comparison with the received components of the rotating pattern so that the receiver may determine its azimuth relative to the beacons antenna system.

I SUMMARY OF THE INVENTION The object of the present invention is to provide an omnidirectional beacon antenna providing an improved vertical radiation pattern shape.

A feature of the present invention is the provision of an antenna system comprising of a vertical radiating assembly disposed coaxially of a vertical axis; at least one cylinder disposed concentric with and at a first given radial distance from the radiating assembly, the one cylinder carrying on a surface thereof at least one group of vertically disposed parasitic elements; a motor having a hollow drive shaft coupled to the one cylinder to rotate the one cylinder about the radiating assembly, the hollow drive shaft being disposed coaxially of the vertical axis; and an energy feeding arrangement coupled to the radiating assembly for excitation thereof, the feeding arrangement extending through the hollow drive shaft and within the radiating assembly coaxial of the vertical axis.

Another feature of the present invention is the provision of three concentric coaxial lines forming the major portion of the above-mentioned energy feeding arrangement.

Still another feature of the present invention is the provision of a pair of dielectric impedance transformers coupled to the outer concentric coaxial line to feed energy to the two lowest most dipoles, a combination of dielectric and metallic impedance transformers coupled to the intermediate concentric coaxial line to feed energy to the intermediate four dipoles and a combination of dielectric and metallic impedance transformers coupled to the innermost concentric coaxial line to feed energy to the five top most dipoles BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other features and objects of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross sectional view, partially in elevation, of an antenna system in accordance with the principles of the present invention;

FIG. 2 is a cross sectional view, partially in elevation, illustrating the details of that portion of the antenna of this invention encircled by circle A of FIG. 1;

FIG. 3 is a cross sectional view, partially in elevation, of the input to the energy feeding arrangement of FIG. 1; and n FIG. 4 is a cross sectional view, partially in elevation, of the central radiating assembly of FIG. 1 and the associated energy feeding arrangement therein.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, there is illustrated therein the omnidirectional TACAN beacon in accordance with the principles of this invention including the following main assemblies: Pedestal 1, rotating assembly 2, vertical or central radiating assembly or array 3, and radome 4 to protect the rotating assembly 2 and central array 3 from the weather.

Central radiating array 3 includes a tubular choke section 5 to prevent the flow of current down the feed line to the input of the

energy feeding arrangement

6 and 11 cylindrical halfway dipoles 7a-7k including at the central feed point of each dipole a dielectric spacer 8a-8k to provide physical support and desired separation for the quarter wavelength sections 9a-9k and 10a-10 forming dipoles 7a-7k. Spacers 8a-8k are made of a low electrical energy low dielectric material at the operating frequency of the antenna system, such as styrafoam. The dipoles 7a-7k in their vertically stacked arrangement are completely enclosed by a tubular dielectric sleeve 1 1, where the dielectric material has a characteristic so as not to attenuate the radiation of energy from the dipoles, such as filament wound epoxy fiberglass.

Energy feeding arrangement 6 extends from within assembly 1 through the hollow shaft 12 of motor 13 supported from plate 14 of assembly 1 into and through array 3 to feed the various dipoles 7a-7k as will be explained hereinbelow with reference to FIG. 4. Bracket 15 is clamped tightly to the outer coaxial line of arrangement 6 and provides in conjunction with shaft 12 and the mount for motor 3 a lower support for array 3. Bracket 15 is secured to motor 13 which in turn is secured to plate 14 thereby providing the necessary mechanical support for array 3.

Rotating assembly 2 includes two cylinders, cylinder 16 at one radial distance from the vertical axis of array 3 and cylinder 17 at a greater radial distance from the vertical axis of array 3. Cylinders l6 and 17 are supported at their lower end by the cooperation of base plate 18 and

brackets

19 and 20 and at their upper end by an upper plate 21 connected to the side wall of cylinder 17 and brackets 22 connected between plate 21 and cylinder 16.

Cylinder 16 carries on its outer surface one group of parasitics and cylinder 17 carries nine groups of parasitics equally spaced on the circumference of the outer surface thereof. These two

cylinders

16 and 17 carrying their respective groups of parasitic elements are used to produce the characteristic TACAN modulation. in one arrangement of parasitic elements shown in FIG. 1, cylinder 16 carries seven vertically aligned and spaced parasitics 23a-23g of varying length extending coextensive with the radiating dipoles of array 3. The length of parasitics 23a-23g, the spacing between adjacent ones of parasitics 23a-23g and the relation of parasitics 23a-23g to dipoles 7a-7k are determined empirically to provide the desired modulation and improved vertical radiation pattern shape. Each group of parasitic elements on cylinder 17 contain separate and distinct parasitics 25a-25j arranged in a predetermined vertically aligned and spaced matter and three separate and distinct parasitics 26a-26 equally spaced between adjacent ones of the nine groups. An illustrative arrangement on one group of parasitics 25a-25j and 26a 26c. Here again the length of parasitics 25a25j and 26a-26c, the spacing between adjacent ones of parasitics 25a-25j and 26a and 26c and the relation of parasitics 25a25j and 26a-26 to each other and to dipoles 7a-7k are determined empirically to provide the desired harmonic pattern and improved vertical radiation pattern shape.

Cylinders

16 and 17 are thin wall filament would epoxy fiberglass cylinders with the various parasitic elements attached to the appropriate cylinder with epoxy resin and an overlay of a thin strip of glass cloth. The parasitic elements absorb and reradiate energy. When the parasitics are rotated about the central array they generate a modulation. An empirical design as to the length an relative location with respect to dipoles 7a-7k is required to assure that the modulation energy stays in phase with the carrier and tracks the carrier in elevation both above and below the horizon in accordance with the requirements for generating a TACAN signal.

Cylinder 16 just below the central dipole 7f carries thereon an aluminum disc 40 supported by a dielectric ring 41 having a dielectric material such as bakelite. Ring 41 has a vertical aperture therein to permit the passage of parasitic 23d. The purpose of disc 40 is to reflect radiation from the upper six dipoles 7f-7k to cooperate in producing the desired, improved vertical radiation pattern shape.

Referring to FIG. 2, there is illustrated therein a detailed cross section, partially in elevation, of that portion of FIG. 1 encircled by a circle labeled A to show the upper bearing arrangement to permit the rotation of the rotating assembly 2 about the central array 3 and also to support the central array 3 from its top most point.

The top wall of radome 4 is secured to bracket 28 through which setscrew 29 is threaded to engage the top, member 30, of central array 3 with locknut 31 holding setscrew 29 in position and to lock member 30 in position in cooperation with yoke portion 280 and stud 32 extending through member 30. Central array 3 also includes a bearing surface 33 connected to member 30. Bearing 34 rotates about surface 33. Bearing 34 is secured in position by the cylindrical bracket 35 which in turn supports cylindrical bracket 22 to which cylinder 16 is secured. A cup shaped member 36 extends from bearing surface number 33 and is secured to dielectric cylinder 11 as illustrated. Internally of member 36 is a spring 37 engaging wall 38 of member 36 and the top surface of a member 39 engaging the inner portion of the quarter wavelength section 10k of dipole 7k. With this arrangement, the top of array 3 is spring-loaded by spring 37 to hold it in the proper vertical orientation and yet permit the rotating assembly 2 to rotate about the vertical axis of array 3.

Referring to FIG. 3, there is illustrated therein the arrangement at the lower end of array 3 enabling the rotation of assembly 2 and the manner in which rotation is imparted to assembly 2. Array 3 includes a bearing surface 42 engaging bearing 43 which is secured to hub 44 carrying plate 18. The hollow shaft 12 ofmotor 13 engages hub 44 at surface 45 and has secured thereto a torque tube 46 which is threaded into hub 44 at point 47. Shaft 12 and torque tube 46 together with hub 44 cooperate to impart rotation to assembly 2 when driven by motor 13. Motor 13 is secured to plate 14 and includes thereon a cylindrical bracket 48 to which is secured clamp 15 by means of member 49 to provide a support for the coaxial lines of the feed arrangement 6 and also, due to the integral arrangement of feed arrangement 6 and dipoles 7a-7k, supports array 3 in the desired vertical, coaxial orientation with the vertical axis of the antenna system.

As previously mentioned, array 3 consists of eleven cylindrical dipoles 7a-7k. The RF (radio frequency) current and RF phase radiated by each dipole is individually controlled by the length and impedance of the transmission line to that element. Several of these transmission lines are present within array 3 itself and will be described hereinbelow. The transmission lines within array 3 form a part of the energy feeding arrangement 6 and are combined within array 3 itself so that only three concentric, coaxial transmission lines enter array 3.

Referring to FIG. 3, energy feeding arrangement 6 includes a semi-rigid coaxial transmission line 50. The outer jacket of line 50 is the center conductor of a second concentric coaxial line whose outer conductor is tube 51. The tube 51 of the second line acts as the center conductor of a third concentric coaxial line having tube 52 as the outer conductor of this third coaxial line. All three of these transmission lines have a characteristic impedance of 50 ohms. RF signal is fed into the second coaxial line through a right angle stub 53 where the center conductor 54 is connected to member 55 which is electrically connected to the outer conductor of transmission line 50. This stub 53 works into a onequarter wavelength shorted section formed by

members

56 and 55 with the short being present at 57. The energy injected into this arrangement is injected between tube 51 and the outer conductor of line 50 thereby energizing the second coaxial line. The third coaxial line is energized by RF signal through the right angle stub 58 whose center conductor 59 is connected electrically to tube 51, the center conductor of the third coaxial line. Stub 58 also works into a one-quarter wavelength shorted section formed by member 60 and tube 51 with the short being present at 61. Thus, the third coaxial line is energized with energy between

tubes

51 and 52. RF signal is fed directly into transmission line 50. The relative amplitude and phase of signals fed into the three concentric coaxial lines are fixed values. The amplitudes are obtained from a three port power divider 62 (FIG. 1) fed from RF energy source 63 and the phases are obtained by inserting the correct length lines, such as at 64 and 65, between power divider 62 and the inputs to the antenna array. The incorporation of variable phase shifters 66 and 67 (FIG. 1) in two of the three input lines permit small (11) adjustments of the direction in elevation of the beam radiated by array 3.

Referring to H6. 4, there now will be described the manner in which the three concentric coaxial lines of the feed arrangement 6 are branched into other transmission lines within array 3 to obtain the desired energy feed to dipoles 7a-7k. RF energy in the third coaxial line between tube 52 and 5 l branch at dielectric spacer 68 following metallic impedance transformer 69 into two transmission lines. One transmission line including one-quarter wavelength dielectric transformer section 70 feeds dipole 7a and the other transmission line including one-quarter wavelength dielectric transformer 71 feeds dipole 7b. Dielectric transformers 70 and 71 as well as the other dielectric transformers adjacent the dipoles are made of a dielectric material having the proper impedance characteristics to match this portion of the transmission line internally of array 3 to the 50 ohm characteristic impedance of the associated one of the three concentric coaxial line. For instance, the transformers such as transformers 70 and 71 were made of rexolite in a reduction to practice the antenna system of this invention.

Energy in the second coaxial line between tubular member 51 and the outer conductor of transmission line 50 branches into two additional transmission lines at dielectric spacer 72. One of these additional trans mission lines including metallic transformers 73 and 74 branches again into two further transmission lines at dielectric member 75. One of these two further transmission lines through the impedance including onequarter wavelength dielectric impedance transformer 76 feeds dipole 7c and the other of these two further transmission lines including onequarter wavelength dielectric impedance transformer 77 feeds dipole 7d. The other of the additional transmission line at spacer 72 including metallic impedance transformer sections 78 and 79 branches again into two further transmission lines at dielectric spacer 80. One of these two further transmission lines including one-quarter wavelength dielectric transformer 8i feeds dipole 7e and the other of these two further transmission lines including one quarter wavelength dielectric impedance transformer 82 feeds dipole 7f. As before the

dielectric impedance transformers

76, 77, 81 and 82 are made of material, such as rexolite, and together with the metallic transformers 73, 74, 78, 79 match the impedance of the associated dipoles 7c-7f to the 50 ohm impedance of the second coaxial line.

Energy present on the first coaxial line 50 emerges therefrom at 83 and branches into two additional transmission lines in one-quarter wavelength dielectric im pedance transformers 84 and 85. These impedance transformers 84 and 85 have a different impedance requirement than the dielectric impedance transformers associated with the dipoles 7a-7k. In a reduction to practice of this antenna the impedance characteristic requirement was satisfied by teflon. One of these two additional transmission lines including dielectric impedance transformer 84, the path between tubular member 51 and the outer conductor of line 50, dielectric spacer 86 and dielectric spacer 87 feeds dipole 7g. The other of these two additional transmission lines including dielectric impedance transformer dielectric spacer 88 branches into two further transmission lines. One of these two further transmission lines including metallic impedance transformers 89 and 90 and dielectric spacer 91 branches into two other transmission lines, one including one-quarter wavelength impedance transformers 92 feeding dipole 7h and the other including one-quarter wavelength impedance transformer 93 feeds dipole 7i. The other of two further transmission lines at spacer 88 including metallic impedance transformers 94 and 95 and dielectric spacer 96 branches into two other transmission lines, one including one-quarter wavelength impedance transformer 97 feeds dipole 7j and the other including one-quarter wavelength impedance transformer 98 feeds dipole 7k.

As should be apparent, the energy to the dipoles 7a-7k are fed so that the first two lower most dipoles 7a and 7b are fed from the third concentric coaxial line, the intermediate four

dipoles

7c, 7d, 7e and 7f are fed from the second concentric coaxial line and the five top most dipoles 7g, 7h, 7i, 7j and 7k are fed from the central coaxial line.

It will also be appreciated that the energy to the various branching points and, hence, to their associated dipoles travels a different path length with the energy in transmission line 50 traveling the longest length path and the energy in the outer or third coaxial line traveling the shortest length path in the array. To make the energy travel the same length to the dipoles,

lines

64 and 65 are inserted as illustrated in FIG. 1 to feed the second and third coaxial lines so that in effect the energy travels the same length path from the energy source 73 to the associated dipoles of the transmission lines.

The amplitudes and phases required to obtain the desired distribution of currents to obtain the improved vertical radiation pattern shape the values of amplitude and phases at each dipole was first determined mathematically without regard to the effect of mutual coupling between the array dipoles themselves, or the mutual coupling between the array dipoles and the parasitic arrays. A prototype array was then fabricated on the basis of these mathematically derived currents and phases which resulted in the dielectric impedance transformers, such as transformers 70 and 71, being located symmetrically with respect to the separation between dipoles 7a and 7b. The prototype model was then modified empirically to compensate the effects of the mutual coupling to obtain the desired carrier patterns and particularly the desired vertical radiation pattern shape. This empirical modification resulted in a shift of the impedance transformers, such as transformers 70 and 71, so that such as dipole 7a was fed by phase advanced current and the dipole 7b was fed by phase retarded to utilized or otherwise compensate for existing mutual coupling between the dipoles of the array and the parasitic elements of the rotating assembly 2 thereby resulting in a compromise to achieve the desired improved shape of the vertical radiation pattern.

While we have described above the principles of our invention in conjunction with specific apparatus, it is to be clearly understood that this description is only made by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. An antenna system comprising:

a vertical radiating assembly disposed coaxially of a vertical axis;

at least one cylinder disposed concentric with and at a first given radial distance from said radiating assembly, said one cylinder carrying on a surface thereof at least one group of vertically disposed parasitic elements;

a motor having a hollow drive shaft coupled to said one cylinder to rotate said one cylinder about said radiating assembly, said hollow drive shaft being disposed coaxially of said vertical axis; and

an energy feeding arrangement including a plurality of concentric coaxial lines coupled to said radiating assembly for excitation thereof, said plurality of concentric coaxial lines extending through said hollow drive shaft and within said radiating assembly coaxially of said vertical axis.

2. A system according to claim 1, wherein said radiating assembly includes a plurality of vertically disposed and aligned cylindrical half wavelength dipoles 3. A system according to claim 1, wherein said radiating assembly includes N vertically disposed and aligned cylindrical half wavelength dipoles, where N is an odd integer greater than one; and

said one cylinder further carries a disc extending radially outward from the outer surface of said one cylinder and disposed vertically below the central one of said dipoles.

4. A system according to claim 1, wherein said plurality of concentric coaxial lines includes three concentric coaxial lines.

5. An antenna comprising:

a vertical radiating assembly disposed coaxially of a vertical axis;

an energy feeding arrangement coupled to said radiating assembly for excitation thereof, said feeding arrangement extending through said hollow drive shaft and within said radiating assembly coaxially of said vertical axis;

said radiating assembly including eleven vertically disposed and aligned cylindrical half wavelength dipoles;

said one group of parasitic elements including seven parasitics disposed in a predetermined vertical spaced relation coextensive with said radiating assembly; and

6. A system according to claim 5, further including a second cylinder disposed concentric with and at a second given radial distance from said radiating assembly and coupled to said motor for synchronous rotation of both said one and said second cylinders by said motor about said radiating assembly, said second given radial distance being greater than said first radial distance, said second cylinder carrying on a surface thereof nine groups of circumferentially spaced parasitic components, each of said groups of parasitic components including 10 parasitics disposed in a predetermined vertical spaced relation coextensive of said radiating assembly, and

three parasitics disposed in a predetermined vertical spaced relation disposed vertically intermediate the ends of said radiating assembly and spaced circumferentially intermediate adjacent ones of said groups of parasitic components.

7. An antenna system comprising:

a vertical radiating assembly disposed coaxially of a vertical axis;

said feeding arrangement including three concentric coaxial lines said three concentric coaxial lines including a first coaxial transmission line having an inner conductor and an outer conductor disposed coaxially of said vertical axis,

a second coaxial transmission line having said outer conductor of said first line as its inner conductor and a first tubular member concentric of said outer conductor of said first line as its outer conductor, and

a third coaxial transmission line having said first tubular member as its inner conductor and a second tubular member concentric of said first tubular member as its outer conductor.

8. A system according to claim 7, further including a source of radio frequency energy, and

a three port power divider coupled to said source;

and wherein said feeding arrangement includes a fourth coaxial transmission line coupled directly between a first port of said power divider and said first coaxial line,

a fifth coaxial transmission line coupled to a second port of said power divider,

a first right angle stub coupled to said fifth line,

a first one-quarter wavelength shorted section coupled between said first stub and said second coaxial line,

a sixth coaxial transmission line coupled to a third port of said power divider,

a second right angle stub coupled to said sixth line,

and

a second one-quarter wavelength shorted section coupled between said second stub and said third coaxial line.

9. A system according to claim 8, wherein said feeding arrangement includes a first adjustable phase shifter coupled between said second port of said power divider and said fifth line, and

a second adjustable phase shifter coupled between said third port of said power divider and said sixth line,

said first and second phase shifter enabling an adjustment in the elevation of the beam radiated by said radiating assembly.

10. A system according to claim 8, wherein said radiating assembly includes 7 7 ll vertically disposed and aligned cylindrical half wavelength dipoles, and

the length of said fourth, fifth and sixth lines are selected to provide substantially equal path lengths to each of said eleven dipoles.

11. A system according to claim 10, wherein said third line feeds the lower two of said dipoles,

said second line feeds the intermediate four of said dipoles, and

said first line feeds the higher five of said dipoles.

12. A system according to claim 10, wherein said feeding arrangement further includes within said radiating assembly a first transmission path having a first one-quarter wavelength dielectric impedance transformer coupled between said third line and the first of said dipoles,

a second transmission path having a second onequarter wavelength dielectric impedance transformer coupled between said third line and the second of said dipoles,

a third transmission path having first and second series coupled one-quarter wavelength metallic impedance transformers coupled to said second line,

a fourth transmission path having a third one-quarter wavelength dielectric impedance transformer coupled between one of said first and second metallic transformers and the third of said dipoles,

a fifth transmission path having a fourth one-quarter wavelength dielectric impedance transformer coupled between one of said first and second metallic transformers and the fourth of said dipoles,

a sixth transmission path having third and fourth series coupled one-quarter wavelength metallic impedance transformers coupled to said second line,

a seventh transmission path having a fifth one quarter wavelength dielectric impedance transformer coupled between one of said third and fourth metallic transformers and the fifth of said PD es,

an etg th transmission path having a sixth onequarter wavelength dielectric impedance transformer coupled between one of said third and fourth metallic transformers and the sixth of said dipoles,

a ninth transmission path having a seventh one quarter wavelength dielectric impedance transformer coupled between said first line and the seventh of said dipoles,

a tenth transmission path having an eighth onequarter wavelength dielectric impedance transformer coupled to said first line,

an eleventh transmission path having fifth and sixth series coupled one-quarter wavelength metallic impedance transformers coupled to said tenth path,

a twelfth transmission path having a ninth onequarter wavelength dielectric impedance transformer coupled between one of said fifth and sixth metallic transformers and the eighth of said dipoles,

a thirteenth transmission path having a tenth onequarter wavelength dielectric impedance transformer coupled between one of said fifth and sixth metallic transformers and the ninth of said dipoles,

a fourteenth transmission path having seventh and eighth series coupled one-quarter wavelength metallic impedance transformers coupled to said tenth path,

a fifteenth transmission path having an eleventh onequarter wavelength dielectric impedance transformer coupled between one of said seventh and eighth metallic transformers and the tenth of said dipoles, and

a sixteenth transmission path having a twelfth one quarter wavelength dielectric impedance transformer coupled between one of said seventh and eighth metallic transformers and the eleventh of said dipoles.

Claims

1. An antenna system comprising: a vertical radiating assembly disposed coaxially of a vertical axis; at least one cylinder disposed concentric with and at a first given radial distance from said radiating assembly, said one cylinder carrying on a surface thereof at least one group of vertically disposed parasitic elements; a motor having a hollow drive shaft coupled to said one cylinder to rotate said one cylinder about said radiating assembly, said hollow drive shaft being disposed coaxially of said vertical axis; and an energy feeding arrangement including a plurality of concentric coaxial lines coupled to said radiating assembly for excitation thereof, said plurality of concentric coaxial lines extending through said hollow drive shaft and within said radiating assembly coaxially of said vertical axis.

2. A system according to claim 1, wherein said radiating assembly includes a plurality of vertically disposed and aLigned cylindrical half wavelength dipoles

3. A system according to claim 1, wherein said radiating assembly includes N vertically disposed and aligned cylindrical half wavelength dipoles, where N is an odd integer greater than one; and said one cylinder further carries a disc extending radially outward from the outer surface of said one cylinder and disposed vertically below the central one of said dipoles.

5. An antenna comprising: a vertical radiating assembly disposed coaxially of a vertical axis; at least one cylinder disposed concentric with and at a first given radial distance from said radiating assembly, said one cylinder carrying on a surface thereof at least one group of vertically disposed parasitic elements; a motor having a hollow drive shaft coupled to said one cylinder to rotate said one cylinder about said radiating assembly, said hollow drive shaft being disposed coaxially of said vertical axis; and an energy feeding arrangement coupled to said radiating assembly for excitation thereof, said feeding arrangement extending through said hollow drive shaft and within said radiating assembly coaxially of said vertical axis; said radiating assembly including eleven vertically disposed and aligned cylindrical half wavelength dipoles; said one group of parasitic elements including seven parasitics disposed in a predetermined vertical spaced relation coextensive with said radiating assembly; and said one cylinder further carries a disc extending radially outward from the outer surface of said one cylinder and disposed vertically below the central one of said dipoles.

6. A system according to claim 5, further including a second cylinder disposed concentric with and at a second given radial distance from said radiating assembly and coupled to said motor for synchronous rotation of both said one and said second cylinders by said motor about said radiating assembly, said second given radial distance being greater than said first radial distance, said second cylinder carrying on a surface thereof nine groups of circumferentially spaced parasitic components, each of said groups of parasitic components including 10 parasitics disposed in a predetermined vertical spaced relation coextensive of said radiating assembly, and three parasitics disposed in a predetermined vertical spaced relation disposed vertically intermediate the ends of said radiating assembly and spaced circumferentially intermediate adjacent ones of said groups of parasitic components.

7. An antenna system comprising: a vertical radiating assembly disposed coaxially of a vertical axis; at least one cylinder disposed concentric with and at a first given radial distance from said radiating assembly, said one cylinder carrying on a surface thereof at least one group of vertically disposed parasitic elements; a motor having a hollow drive shaft coupled to said one cylinder to rotate said one cylinder about said radiating assembly, said hollow drive shaft being disposed coaxially of said vertical axis; and an energy feeding arrangement coupled to said radiating assembly for excitation thereof, said feeding arrangement extending through said hollow drive shaft and within said radiating assembly coaxially of said vertical axis; said feeding arrangement including three concentric coaxial lines said three concentric coaxial lines including a first coaxial transmission line having an inner conductor and an outer conductor disposed coaxially of said vertical axis, a second coaxial transmission line having said outer conductor of said first line as its inner conductor and a first tubular member concentric of said outer conductor of said first line as its outer conductor, and a third coaxial transmission line having said first tubular mEmber as its inner conductor and a second tubular member concentric of said first tubular member as its outer conductor.

8. A system according to claim 7, further including a source of radio frequency energy, and a three port power divider coupled to said source; and wherein said feeding arrangement includes a fourth coaxial transmission line coupled directly between a first port of said power divider and said first coaxial line, a fifth coaxial transmission line coupled to a second port of said power divider, a first right angle stub coupled to said fifth line, a first one-quarter wavelength shorted section coupled between said first stub and said second coaxial line, a sixth coaxial transmission line coupled to a third port of said power divider, a second right angle stub coupled to said sixth line, and a second one-quarter wavelength shorted section coupled between said second stub and said third coaxial line.

9. A system according to claim 8, wherein said feeding arrangement includes a first adjustable phase shifter coupled between said second port of said power divider and said fifth line, and a second adjustable phase shifter coupled between said third port of said power divider and said sixth line, said first and second phase shifter enabling an adjustment in the elevation of the beam radiated by said radiating assembly.

10. A system according to claim 8, wherein said radiating assembly includes 11 vertically disposed and aligned cylindrical half wavelength dipoles, and the length of said fourth, fifth and sixth lines are selected to provide substantially equal path lengths to each of said eleven dipoles.

11. A system according to claim 10, wherein said third line feeds the lower two of said dipoles, said second line feeds the intermediate four of said dipoles, and said first line feeds the higher five of said dipoles.

12. A system according to claim 10, wherein said feeding arrangement further includes within said radiating assembly a first transmission path having a first one-quarter wavelength dielectric impedance transformer coupled between said third line and the first of said dipoles, a second transmission path having a second one-quarter wavelength dielectric impedance transformer coupled between said third line and the second of said dipoles, a third transmission path having first and second series coupled one-quarter wavelength metallic impedance transformers coupled to said second line, a fourth transmission path having a third one-quarter wavelength dielectric impedance transformer coupled between one of said first and second metallic transformers and the third of said dipoles, a fifth transmission path having a fourth one-quarter wavelength dielectric impedance transformer coupled between one of said first and second metallic transformers and the fourth of said dipoles, a sixth transmission path having third and fourth series coupled one-quarter wavelength metallic impedance transformers coupled to said second line, a seventh transmission path having a fifth one-quarter wavelength dielectric impedance transformer coupled between one of said third and fourth metallic transformers and the fifth of said dipoles, an eighth transmission path having a sixth one-quarter wavelength dielectric impedance transformer coupled between one of said third and fourth metallic transformers and the sixth of said dipoles, a ninth transmission path having a seventh one-quarter wavelength dielectric impedance transformer coupled between said first line and the seventh of said dipoles, a tenth transmission path having an eighth one-quarter wavelength dielectric impedance transformer coupled to said first line, an eleventh transmission path having fifth and sixth series coupled one-quarter wavelength metallic impedance transformers coupled to said tenth path, a twelfth transmission path havIng a ninth one-quarter wavelength dielectric impedance transformer coupled between one of said fifth and sixth metallic transformers and the eighth of said dipoles, a thirteenth transmission path having a tenth one-quarter wavelength dielectric impedance transformer coupled between one of said fifth and sixth metallic transformers and the ninth of said dipoles, a fourteenth transmission path having seventh and eighth series coupled one-quarter wavelength metallic impedance transformers coupled to said tenth path, a fifteenth transmission path having an eleventh one-quarter wavelength dielectric impedance transformer coupled between one of said seventh and eighth metallic transformers and the tenth of said dipoles, and a sixteenth transmission path having a twelfth one-quarter wavelength dielectric impedance transformer coupled between one of said seventh and eighth metallic transformers and the eleventh of said dipoles.