US2453751A - Antenna reflector system - Google Patents

Description

Nov. 16, 1948. KlNNlER ANTENNA REFLECTOR SYSTEM Filed Aug: 26, 1944 INVENTOR.

MAN/LA 770A Patented Nov. 16, 1948 g 2 453;751 ANTENNA RE'FLEc'ron SYSTEM Donald Kiimier, Philadelphia, :Pzu; as'signbn. by mjesnenassigmnents to Philco Corporation; Rhiladelphia, Pa., a corporation. of Pennsyl- .vama application 'Aagast 26, 1944,- Serial No. 551-340 iii Claims, (01. 250-33135) My invention relates ingeneral to. ultra-high inipedan'c'e matching between the di-pole and frequency signalling systems, and more particu cylindrical wave guide. Accordingly, energy is larly to an improved short wave aritennaq In coupled from the sources. ofoscillation through general, ultra-high frequency directional radiatlf rectangular wave guide a'n'd cylindrical cavity tion antenna systemsare arranged to direct their 5" to the individual di pole radiating unit's. radiated energy against a reflecting surface" which The lengths of the di fp'ol antennae extending determines the field distribution of the radiated into the cylindrical cavity are positioned at a en r I point of maximum field intensity and accord- The antenna; arrays utilized as the coupling iilgly the energy radiated from the e p K link between the source of energy and the main tion of the di-pole is comparatively large"; and reflector usually comprise two (ii-poles properly high radiation efficiency is obtained. This ri-f disposed with respect to the main radiating erg is directed by suitable means against the metallic surface. The correct location of thfiw ai reflecting s 'l' p' t the W e pole antennae has heretofore been a problem; guide. and di -poles and is re 'radi'at'ed into space since energy radiated from these dipo-les and from this main surface. w v directed toward the inainreflecting plate would The di' pole supporting means precludes i'n'ten normally result in interference with the wave fere'nc between these antennae and the ma ff guide feeding the di-polesresultingin distortion reflecting elements since the di pbls are spac in the radiation pattern and directional charac from the supporting means by a suificien't dis;

teristics. t g H 7 2o tan'ce' to prevent the supporti g structure" tram My invention contemplates an ultra-high fre interfering with the radiati fi from the ci cuits quency radiation system which will comaaay' to the reflector. The radiating unit is tartaneliminate the interference problfrli her t gait larly flexible since the (tr- 55185 are so located experienced in signal radiation at ccmtar tivly that various reflectors" may be used to cream high frequencies. In accordance witn m y invention, the aurafletors high frequency radiating systeiii ccii pnses at suit-a lepositions such that the main gu'ld sehtially a main reflecting sur ace w en may may be brough throu'glf the "frequency reflector be parabolic or of any other shape dependent at otlirthana cefitrally lbcait' d s mere.

upon the directional field characteristic deis'i "a; 8 It time an object a: my invent on to are:

Centrally supported upon the reflecting an vide' improved ultra high frequency radiatis a rectangular wave guide energi d from ingstructure.

source of ultra-high frequency energy. This rec her object of my" invention to provide tangula'r wave guide is designed for il'l'l lldiligj dipo es nd amai'n control 6rtne fiem d'istr aghast. tn a also be locatedabcat the an e propagation of the TEormode of the w so' tha't or inter is well understood, this oscillation mode results d thereb in minimum attenuation in a properly amen: A2 further ob t or 11% in A sioned rectangular wave guide; At a suitable" a radiation system utilizing di-fiol'e's n distance from the main reflecting surface; the fromacylindricalwaveguide. Y rectangular wave guide terminates in a tra These and other obje'cts' or \tifu verse cylindrical cavity of one wave guide wave now become apparent froin the following d'e length for the operating frequenc 4 g tailedspecification taken in connection with the The cylindrical cavity is appropriatelymatched accompanying drawings in which with the rectangular wav guide and is propor- Figure 1 is irontview 6f th'radiating' struc tioned for efiicient propagation of the TMci 65- ture;

cillation mode. The ends of the cylindrical cav- Fig. 1a is a perspective view of the showing ity are sealed in a manner to be described. of Fig.1.

Coupled into the sealed ends of the cylindrical Figure 21s a" side View of the structure: i'lliis guide are di-pole radiators each approximately trated'inFigure L wave length long. These di-pole radiaters 5 Figure 3* isa front View of an end plate for are axially mounted upon the cylindrical wave acylindrical cavity. 7 guide such that approximately /4 wave length Figure 4 is" a cross sectional view of the end section extends into the cylindrical guide and ap= plates taken 310115; the line A -'4" of Figure 3:-

proximately wave length is exposed. Slight Figure5 isa front view of a'modified endplate adjustments of the lengths are made to Secure for acayity; and

- 3 Figure 6 is a cross-sectional view taken along the line 6-6 of the end plate illustrated in Figure 5.

Referring now to Figures 1 and 2, there is shown a large metallic reflecting surface parabolically or otherwise shaped to provide a desired field distribution. Extending through a centrally located opening l2 in the main reflector H is a rectangular wave guide l3. The wave guide l3 is joined at its lower end M to the source of energy to be radiated.

Since the TE01 mode of propagation is transmitted through wave guideswith minimum attenuation, the rectangular wave guide I3 is proportioned for the propagation of this oscillation mode.

The upper end of the rectangular wave guide |3 is suitably cut to support the circular wave guide |5. A large opening is cut into the lower surface of circular wave guide 5 to provide a continuous passage from. the inside ofwave guide I3 to the inside of wave guide |5. The transition between the rectangular wave guide |3 and the circular guide I5 is such that proper matching is obtained between the two so that a maximum energy transfer is effected.

The cylindrical section I5 is so proportioned that propagation therein will occur at the TM01 mode. The field distribution for this mode of oscillation within the cylindrical section 5 is such that maximum electric field intensity is obtained along the axis of the cylinder. The length of the cylindrical section I5 is one wave length so that proper resonance may be established therein.

Suitably supported upon the ends of the cylindrical wave guide l5 are di-pole antennae 2| and 22. Each of these individual di-poles is approximately wave length long, and extends as at 23 into the cylindrical section l5 for approximately A; wave length. Accordingly, approximately wave length of each of the di-poles 2| and 22 is exposed. The supporting means for the di-pole antennae 2| and 22 provide suitable insulation between the di-poles and the walls of the cylindrical guide l5. These supports will be described in greater detail later. Accordingly it may be seen that energy from the oscillating source imguide i3 is carried therepressed upon the wave by through the opening.|2 in the reflecting surface I and into the cylindrical section l5 wherein a resonant condition is established. The di-poles 2| and 22 absorb energy from the oscillating system within the wave guide l5 and this energy is radiated from the exposed ends thereof.

As illustrated in Figures 1 and 2, and as will be described in greater detail later, parasitic reflectors 3| and 32 are provided for the di-poles 2| and 22 respectively.

These reflectors 3| and 32 are mounted directly above their associated di-poles, and are joined electrically to the walls of the wave guides l5. As is well understood, these parasitic reflectors when combined with their associated di-poles result in directional radiation towards the main reflecting surface Accordingly the greater part of the energy flowing from di-poles 2| and 22 is directed to the reflecting surface whereat it is re-radiated into space in a directional manner as determined by the nature of the reflecting surface As illustrated, the structure provides for minimum interference between the di-pole radiators and the reflecting surface since the structure is so arranged that di-poles 2| and 22 are spaced substantially from the surface of the support and wave guide |3.

Obviously the nature of the reflectors for directing the radiating energy towards the main reflecting plate may be varied as required by the field distribution desired. For example, the reflectors 3| and 32 which are connected to the cylindrical guide l5 may be replaced by corner reflectors which will also serve to direct the greater part of the radiated energy against the reflecting plate The di-pole supporting means are illustrated in Figures 3 to 6 inclusive. In one modification of a di-pole support as illustrated in Figures 3 and 4, a circular metallic plate 4| serves as the end plate for the cylindrical cavity |5. Thus, the metal plate 4| is equal in diameter to the wave guide 5 and has an opening 42 to support an insulating'insert 43 which may be secured in any convenient manner. Centrally located in the insulating insert 43 is the di-pole 2| which as illustrated in Figure 4 extends through a perforation 44 within the insulating insert 50 that approximately 4 wave length of the di-pole will be positioned within the cavity l5 and the other approximate wave length of the di-pole 2| will serve as the radiating element.

The parasitic reflector 3| approximately wave length long is supported within a perforation 45 in the metallic end plate 4|. The distance between the di-pole radiator 2| and the parasitic reflector 3| is selected to give the desired radiation toward the primary reflector. It may thus be seen from Figures 3 and 4 that the insulating insert 43 is approximately wave length in diameter. The end plate structure of Figures 3 and 4 is of course used at each of the ends of the cylinposed length of the di-pole radiator 2| so drical wave guide I5. Although the wave guide I3 is shown centrally located in the reflector it will now be obvious that it may be brought in from other angles as from the side; since the secondary reflector 3| may be rotated about the main di-pole 2| to provide desired directing towardthe primary reflector Another type of di-pole support is illustrated in Figures 5 and 6. Here again, as in the type illustrated in Figures 3 and 4, a metallic end plate 5| of the diameter of the cylindrical guide I5 is utilized as the basic supporting member. An essentially circular perforation 52 of approximately wave length diameter is concentrically located within the end plates 5|. Extending into the circular opening 52 is an integral extension 53 of the metallic plate 5|. The extension 53 is A wave length long and accordingly reaches the center of the end plate 5|. As illustrated, a di-pole radiator, such as 2|, approximately /2 wave length long is securely supported upon the inner end of the metallic extension 53 such that approximately 2; wave length of the di-pole extends normal to each surface of the metallic end plate 5|.

As is well understood in the art, a A; wave length of transmission lines short circuited at one end presents comparatively high impedance at its input terminals. In this manner the wave length metallic supporter 53 serves as an insulator between the metallic end plate 5| and the attached di-pole 2|. In order to obtain the proper directional characteristics, a parasitic reflector 55 approximately 4 wave length is secured within a perforation 51 in the metallic end plate 5|. The reflector 56 is positioned directly above the hat energy reflected from the la tlter di-pole is an rec ted against the metallic r'efl'e'ct'or ll.

In the application of an end plate as illustrated in Figures 5 and 6, the plates are securely fastened to "the ends of the cylindrical cavity l5 in the manner illustrated in Figures 1 and 2. Accordingly it may be seen that the radiating structure illustrated in Figures 1 and '2 provides a convenient flexible means for directional signal transmissions. The radiating iii-poles are conveniently coupled to the energy source in a manner which provides a maximum overall efliciency and energy transfer.

The field distribution of the radiating signal may be varied simply by a variation in the reflecting surface or in the type of reflector used behind the radiating di-poles.

It is thus evident that this flexible radiating structure may be subject to various modifications without departing from the scope of the invention. Accordingly I prefer not to be bound by the specific disclosures hereinabove set forth but by the appended claims.

I claim:

1. An ultra-high frequency antenna system comprising a reflector; di-poles each approximately one-half wave length long for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a completely enclosed cavity resonator, said dipoles being insulatedly mounted in said cavity resonator.

2. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a completely enclosed and sealed cavity resonator, said di-poles being insulatedly mounted in said cavity resonator at the point of maximum field intensity.

3. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, said di-poles being insulatedly mounted in said cavity resonator and protruding therefrom.

4. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, said di-poles being insulatedly mounted in said cavity resonator and protruding therefrom a quarter of a Wave length.

5. An ultra-high frequency antenna system comprising a reflector; (ii-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, said di-poles being insulatedly mounted in said cavity resonator extending within said cavity resonator for one quarter of a wave length and protruding from said cavity resonator for one quarter of a Wave length.

6. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, and a wave guide of rectangular cross-section energized by high frequency energy coupled to said cavity resonator, said di-poles being insulatedly mounted in said cavity resonator.

7. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for prdpagatnigenergy to said iii-poles including a cavity resonator, and a wave game or rectangular cross -se'ction energized by high frequency energy coupled to said cavity resonator, said di-poles being insulatedly mounted in said cavity resonator at opposite ends thereof.

8. An ultra-high frequency antenna system comprising a reflector; (ii-poles for radiating energy to said reflector and a feeding system for propagating energy to said di' poles including a one wave :guide Wave length cavity resonator and a Wave guide of rectangular cross-section energized by high frequency energy coupled to said cavity resonator, said di-poles being insulatedly mountedin said cavity resonator.

9. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a one wave guide Wave length cavity resonator and a wave guide of rectangular cross-section energized by high frequency energy coupled to said cavity resonator, said di-poles being insulatedly mounted in said cavity resonator at opposite ends thereof.

10. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, said di-poles being insulatedly mounted in said cavity resonator and parasitic reflectors extending from said cavity resonator,

11. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, and a wave guide of rectangular cross-section energized by high frequency energy coupled to said cavity resonator, said di-po1es being insulatedly mounted in said cavity resonator, said rectangular cross-sectional wave guide extending through an opening in said reflector and said cavity resonator having its axis at right angles to the longitudinal axis of said wave guide at the point of coupling.

12. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a wave guide and a cavity resonator proportioned to propagate the TM01 mode, said wave guide and cavity forming a continuous passage, said di-poles being insulatedly mounted in said cavity resonator.

13. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator proportioned to propagate the TM01 mode and a wave guide of rectangular crosssection proportioned for the propagation the TEM mode, said di-poles being insulatedly mounted in said cavity resonator.

14. An ultra-high frequency antenna system comprising a reflector; di-poles for radiating energy to said reflector and a feeding system for propagating energy to said di-poles including a cavity resonator, and a wave guide of rectangular cross-section energized by high frequency energy coupled to said cavity resonator, said di-poles being insulatedly mounted in said cavity resonator, said rectangular cross-sectional wave guide extending through an opening centrally located in said reflector and said cavity resonator having its 8 exis-at right angles to the longitudinal axis of Number Name Date said wave guide at the point of coupling. 2,125,969 Turner Aug. 9, 1938 DONALD KINNIER. 2,253,501 Barrow Aug. 26, 1941 2,356,414 Linder Aug. 22, 1944 REFERENCES CITED 5 2,370,058 Lindenblad Feb. 20, 1945 The following references are of record in the THER REFERENCES e of thls patent Barrow and Mieher, Natural Oscillations of UN TED ST ES PATENTS Electrical Cavity Resonators, Proc. I. R. E. April Number Name Date 10 1940, vol. 28, pages 184-191.

2,009,368 Usselman July 23, 1935

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