US1912754A - Antenna - Google Patents

Description

June 6, 1933. O G ET AL 1,912,754

ANTENNA Filed June 9, 1950 INVENIORS OTTO BOHM RU DOLF BECHMANN BY awgosmsrem 2 AT' RN 40 central radiator.

Patented June 6, 1 933 PATEN- fFIc E OTTO BOHM, RUDOLF BECI-H/IANN, AND HANS OTTO BOOSENSTEIN, OF BERLIN, GER- MANY, ASSIGNORS TO TELEFUNKEN GBAZPHIE M. B. I-I., or BERLIN, GERMANY, A CORPORATION on GERMANY GESELLSCHAFT FUR DRAHfT'Losn TELET ANTENNA.

Application filed June 9, 1930, Serial No.

In the accompanying drawing, Figure 1 illustrates an antenna system embodying the principles of my invention, and p 7 Figure 2 is given by way of explanation thereof.

One embodiment of the basic-idea of the l i i y p a invention is diagrammatically illustrated'in Figure 1. In this arrangement the radiator 7 system comprises a vertical centrally dis posed antenna at having a length of )t/l: in

" which there flows a current J and eight vertical antenna-b of about the same/height and forming around the central antenna a circle of a radius of )t/lz. The auxiliary radiators are fed with currents i presenting a phase displacement angle of 180 degrees in relation tothe current of the Presupposing a ground of perfect conductivity and sinusoidal current distrib-ution in, the various antennae it is possibl by the" superposition of the space radiation fields of all of the radiators to calculate thes pace' sin 0 sin cos is obtained is derived below.

459,863, and' in German June 11,1929;

distribution for the Poynting vector (radiation vectorof'electromagnetic energy). 'It is found, for instance, for the system illustrated in Figure 1 that the value S of the Poynting vector for any given point whose azimuth angle with the vertical plane is given by the line AB, Figure 1, andwhose zenith angle (angle between the vertical plane and the connecting line of the point in question and the center a of the antenna system) there holds goods the following equation:

where G a constant, while b is given by this formula:

sin 6 sin d is the radius of the circle and on the ratio of 2 times the current J in the outer antennae and the current J in the inner antenna.

, 'For' any direction characterized by 0 and it is possible to determine by the aid of the above formula the radiation amplitude in a definite unit distance. I The manner in which the above mathematical expression for radiation characteristic In the example cited 8 radiators are uniformly and regularly arranged around a circle having a radius 03. All of these are ex-, cited under co-phasic conditions, and an additional radiator is located centrally. All of ,9

- the aerials areof quarterwave length. The radiators areahove a ground or soil possess-- ing infinitely high conductivity, and this is duly considered by the addition of the image. Using as a basis rectangular coordinates w, y, a, or spherical polar coordinates r, (p and 6 respectively, between which there is to hold good the relation there results for the mean time-Value of the e Poynting vector S expressed by a complex formula 4 z'lazzo Introducing for the sake oforevity rt (cos Urdu sin (2 cos b) cos (lad sin sin qS) +cos (kd sint sin(+g)) then i 2 g g e cos(% cos 6) up Where m and y are the coordinates of the base of the radiator, A the current amplitude, and 11/ the phase of the e radiator. C is a constant. N denotes theoperatornorm, i. ei the formation of the absolute e value of the following expression, further I i (Where A=Wave length) and t=y i In the special case Where 8' radiators are uniformly disposed'around a circle of radius (Z', all of Whichare excited under cophasie condition and with the same amplitude A and Where a central radiator is mounted whose amplitude shallbe assumed to be equal to A there is obtained from the above formula if the coordinate origin of the central radiator is fixed, While the base coordinates of the other radiators then sin 0 (p denotes the phase displacement angle hetween the peripheral radiators and the cen' tral radiator, from Which one gets the follow- 111g equation:

0 cos cos 0) sin 6 if for simplieitys sake there has been intro-- duced therein Ji l 05 A0 For further details respecting derivation of the expression reference must be made to, article published in Telefunkenzeitung No.

that the horizontal radiations are equal to each other in both cases, undesired upward radiation is considerably greater When the central antenna a alone is present than when cos, (ltd sin 6 sin eos (kd sin 6 a system as shown in Figure 1 is employed.

cos lcd sin. sin (it f [(ll aocosal/l -l-(ofi SiIi W ly '53,December 1929 Calculation of radiation a different curve or line, and it is not necessary that this curve should be symmetrical. No matter what the superposition of the radiations of each antenna or radiator, it is possible to calculate the distribution of the Poynting vector for the desired position of the auxiliary radiators as a function of the amplitudes and phases of their currents, and

one may then choose those phases and amplitudes of the currents for the various auxiliary antennae which will result in an optimum distribution of the radiations. However, it Would be simpler in this instance to proceed empirically in that for extremely short (ultra-short) Waves, say, of an order of 50 centimeters, a conveniently reduced antenna model is erected and by that the most favorable amplitudes and phases of the various radiators are ascertained from field intensity measurements.

Also the number of the auxiliary antennae may be chosen differently. It is even feasible to operate the auxiliary radiators without supplying them with energy, in other Words, to use them as mere reflectors.

We claim:

1. An antenna system adapted to radiate substantially uniformly in all directions in a horizontal plane comprising a centrally disposed vertical antenna and a plurality of outer vertical antennae located on a circle around said centrally disposed antenna, of a radius equal to one quarter of the communication wave, all of said antennae having a length substantially equal to one quarter of the communication Wave, said outer antennae being fed with currents presenting phase displacement angles of degrees with respect to the current in the central antenna.

2. A. system in accordance with claim 1 having eight outer antennae disposed around said central antenna.

OTTO BOHM. HANS OTTO ROOSENSTEIN. RUDOLF BEGHMANN.

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