# Патент USA US2126531

код для вставкиAug. 9, 1938. P. s. CARTER~ ' 2,126,531 ANTENNA Filed lhflfrch 9, 1956 \ > 2 Sheets-Sheet l y,/' \ . ‘ ‘\e" INVENTOR/ / B > ‘ . ‘ PHILIP S.CAR“FER ' ATTORNEY. - Aug- 9, 1938. P. ,s. CARTER 2,126,531 ANTENNA Filed March 9, 1936 2 Sheets-Sheet 2 1/195 v ‘ 6 900 900 F191. 7 90" ' , ' F198 90" 7'0 TRANSMITTER Fig.9 INVENTOR. ‘ PHILIP 5. CARTER‘ BY ’ ATTORNEY. " Patented Aug. 9, 1938 2,126,531 al UNITED STATES - 7 PATENT =1 i‘OFFICE 2,126,531 _ d ‘f » ANTENNA " V-Philip .sr-Carteryl’ort Je?'erson, N. Y; assignor to . Radio Corporation of America, a corporation ’ of Delaware Application March '9, 1936, .Serial ‘No. 67,785 ‘ 6 Claims. This invention relates to an antenna system (01. 250_3s) for broadcasting vertically polarized waves. ‘ this ?gure of the drawings; then, if I is the Heretoforein order to obtain a high latitudinal ‘concentration of radiation, ‘it has been usual to employ an array of tall ‘radiators which reach total‘ current in all the radiators the current in one radiator is I considerable heights. An arrangement of this sort is very costly, and ‘in most cases it is not possible to obtain equal radiation in all horizontal directions. . ‘ ' radiators-‘nina circle of radius a, as shown in » The number of radiators within an angle d9 is er ‘ The present invention provides an improved antenna system wherein there is obtained sub stantially equal radiation in all horizontal direc tions and a great reduction in undesirable high ~angle radiation. In brief, the invention consists are of concentric circular arrays of vertical radiators ‘spaced apart according to a de?nite mathemati cal law, all of the vertical radiators in each cir cular array ‘being of substantially equal length and energized cophasally with equal currents r1120 while adjacent circular arrays are fed either co phasally or in opposition, depending upon the lengths ‘of the radii of the arrays as measured 21F Now consider that the ?eld Waves arrive.at point P in this sketch, which point is at a su?i- ' cient distance from the circle for all paths to be parallel. Let us now take as reference phase the phase of a wave arriving from an element on the reference axis 9:0. This wave has trav elled a distance R. The Wave from the element 110 has travelled a distance r=R~a sin 9. . a sin 6 25 I have found that for a given ‘total current the ?eld strength of the radiated wave ‘in the .horizontal direction from .a circular array of a where v is the velocity of light. number of vertical radiators is proportional to Jn(‘2wa/>\), where a is the radius of the circle of reference phase by the real part of ‘ l V If .we represent the electric ?eld of the wave 30 I ‘wt Kle' of the ?rst kind with the argument. (ZTra/X). It is thus apparent that for maximum radiation horizontally, the radius must be such as to result ‘ . v 21r KI . they _, KI . 21rd see I ‘Regen/10+ v )d0—Re%61w<t+ )\ )cw minimum. For this condition, J1 of (21ra/i) =0, where J1 is the corresponding ?rst order Bessel function of the ?rst kind. Hence the radii should be roots ‘of the function J1(21ra/)\) . . d6 then the‘ ?eld from the element at 9 is in the function Jo(21ra/)\) being a maximum or ‘ 35 The total ?eld at P is then: This results ‘in values approximately equal to 0.61, 1.12, 1.62, 2.12, 2.62 etc. wavelengths, wherein all radiators ‘in each circular array are fed cophasally, but adjacent circular arrays are fed in phase oppo _ sition. The di?erence in distance is asin 9, to which corre sponds a distance in time and J0(27rCL/7\) is the zero order Bessel function “ 45 10 and the total current in these radiators is: ‘from a central point. These vertical radiators .may either be dipoles or grounded vertical an tennas. Ul n ‘ The invention is not limited to the arrange ment already discussed. It is not necessary in an array of circles to have radii corresponding to all successive roots of the Bessel function ‘mentioned. For instance, it might be desirable to use an array having radii of 0, 1.12, 2.12 etc. wavelengths or 0.61, 1.62, 262 etc. wavelengths, '40 ‘where . 1(7) 21ra is the zero order Bessel function of the ?rst kind. Now, for a given current the magnitude of the 45 ?eld will be a maximum when we .is a maximum or a minimum. 1:111 radiators in the circles in either of these com binations beingrfed cophasally. Another combi nation might be with circles of radii .0, 1.62, 3.12 etc. wavelengths, where the radiators in adja cent circles are fed in phase opposition. 1 ,A' brief mathematical analysis of the theory underlying the present invention will now be given with particular reference to Fig. 10. Let 60 us assume that there are a large number of JrT is the first order Bessel function of the ?rst kind. From the roots of this function we obtain the relations given in the docket. 60 2 2,126,531 No radiation horizontally takes place when the radius a is such that or when a=0.382>\, 0.8801, etc. A better understanding of the invention may be had by referring to the following description in conjunction with drawings wherein: 10 Figs. 1-4, inclusive, illustrate plan views of antennas in accordance with the invention; Figs. 5-8, inclusive, illustrate polar diagrams of the ?eld distribution in any vertical plane of various combinations of individual circular arrays shown in Fig. 1; Fig. 9 shows, by Way of example only, one way of feeding the antenna arrays; and Fig. 10 is a drawing given merely for the pur pose of the theoretical explanation advanced above. systems shown, since other circular arrays may be used which are suitably energized and have as radii roots of the Bessel function named, with out departing from the spirit and scope of the invention. What is claimed is: 1. An antenna comprising a plurality of con centric circular antenna arrays each composed of vertical radiators, the radius of each circular array being such that the zero order Bessel func tion of the ?rst kind, namely J 0(21ra/1) , with the argument (21ra/A) , is a maximum or a minimum, where a is the radius of the circular array, A the wavelength, and high frequency apparatus for energizing the radiators in each circular array 15 cophasally. 2. An antenna comprising a. plurality of con centric circular antenna arrays each composed of vertical radiators, the radii of successive cir cular arrays multiplied by In Fig. l is shown a plan View of one antenna 20 21r arrangement in accordance with the invention, comprising four concentric circular arrays 2, 3, 4, 5 of vertical radiators with a single radiator I at the center. This system may be considered the ?rst kind, J1(21ra/>\) with the argument 25 as consisting of ?ve circular arrays, the inner most array consisting of single radiator I which length, and high frequency apparatus for ener is of zero radius. The radii from the central radiator l to successive arrays are, as indicated, 30 equal to 0.61, 1.12, 1.62 and 2.12 wavelengths, which are successive roots of the Bessel function mentioned above. All the radiators in any one circle are of equal length and energized cophasal ly in any suitable manner and with equal cur T being successive roots of the Bessel function of (21ra/A), where a is the radius and A the wave gizing the radiators in each circular array co phasally but out of phase with respect to the radiators in the adjacent array. 30 3. An antenna comprising a plurality of con centric circular antenna arrays each composed of vertical radiators, the radii of successive cir cular arrays multiplied by to O1 rents, while radiators in adjacent circles are fed are of sufficient number to produce an effect ap proximating a current sheath. If desired, the circular arrays may have currents of different 40 magnitude with respect to one another. Figs. 2 and 3 show plan views of an antenna system wherein the radii of successive arrays correspond to alternate roots of the Bessel func tion named. In both of these ?gures the adja 45 cent circular arrays are fed cophasally. Fig. 4 shows, by way of example, another com bination of circular arrays which may be used, and wherein the radiators in adjacent circular arrays are energized in phase opposition. Fig. 5 is a polar diagram of the ?eld distribu tion in any vertical plane for a single radiator. Fig. 6 is a similar diagram for a circle of radia tors having a radius of 0.61 wavelength. Fig. '7 is a diagram resulting from the combi 55 nation of a circle of radiators having a radius of 0.61 wavelength from a central point and a single radiator at said central point. Fig. 3 is a similar diagram for the system of Fig. 1. Fig. 9 shows one way of feeding all the ra diators in any one circle by means of equal length lines connecting with a main feeder. If the radiators are dipoles, each line would comprise a pair of wires. Similarly, other circular arrays 65 are also fed from the center. To obtain phase opposition or cophasal relation between any two circular arrays, the central connection points of the lines extending to the individual radiators would be joined together by a proper length of 70 line to give the desired phase relation. From the foregoing it will be understood that the invention is not limited to the precise antenna 35 g in phase opposition. The radiators in each circle A being alternate roots of the Bessel function of the ?rst kind, J1(21ra/7\), with the argument (21ra/A), where a is the radius, and 1 the wave length, and high frequency apparatus for ener gizing the radiators in all circular arrays co phasally. 4. An antenna comprising a plurality of con centric circular arrays each composed of ver tical radiators, a single vertical radiator at the 45 center of said arrays, the radius of said ?rst circular array as measured from said center be ing approximately .6121, the radius of the second circular array being approximately 1.121 and that of the third array approximately 1.621, where A 50 is the wavelength, and high frequency apparatus for energizing the radiators in each array co phasally, but adjacent arrays out of phase. 5. An antenna comprising a plurality of con centric circular arrays each composed of vertical 55 radiators, a single vertical radiator at the center of said arrays, the radius of the ?rst of said ?rst circular arrays as measured from said center being approximately 1.121, the radius of said second circular array being approximately 2.121, where A is the wavelength, and high frequency apparatus for energizing the radiators in all arrays cophasally. ‘ 6. An antenna comprising a plurality of con centric circular arrays each composed of vertical radiators, the radius of the ?rst of said arrays as measured from the center being approximately .611, and the radius of the second array being approximately 1.621, where >\ is the wavelength, and means for energizing all the radiators of all 70 arrays cophasally. ’ PHILIP S. CARTER.

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