US1917348A - Antenna - Google Patents

Description

y N. VON KOR'SHENEWSKY 1,917,348

ANTENNA Filed July 12, 1930 INVENTOR NKOLAI JON KORSHENEWSKY ATTORNEY Patented July 11 1933 UNITED STATES PATENT OFFICE NICOLAI VON KORSHENEWSKY, OF BERLIN, GERMANY, ASSIGNOR T O T'ELEFUNKEN GESELLSGHAFT FtiR DRAHTLOSE TELEGRAPHIE M. B. 1-1., OF BERLIN, GERMANY, A

CORPORATION OF GERMANY ANTENNA Application filed July 12, 1930, Serial No.

The object of the present invention is to provide a novel type of antennna partieularly adapted for the reception of short and ultra-short waves. It is known in the prior art that linear oscillators may be employed as receiving antennae, these having a length half that of the incomingwave, coupling of the receiver circuits being effected in the middle of said antennnae, while, when longer antennae were used it was usual to establish the coupling of the receiver circuits at a point where the natural wave of these antennae presented a loop or anti-node.

In the accompanying drawing which is lustrative of the present invention,

Figure 1 illustrates forced and natural current distribution on a linear oscillator one wave length long,

Figure 2 illustrates, according to the present invention the manner of establishing coupling to the radiator of Figure 1,

Figure 3 illustrates the present invention as applied to a linear oscillator two wave lengths long, and

Figure 4 illustrates a directional arrangement utilizing oscillators in accordance with the )resent invention.

Tiis invention discloses the use of receiving antennae having a length equal to that of the incoming wave or a multiple thereof, while the coupling is effected at a distance from the end of the antenna being equal to one-half the wave-length or an odd multiple thereof. The idea from which this invention starts is that the current distribution in the antenna of a length as stated, for an excitation produced by the radiation field, is such that a current loop arises at a point where the anode for the natural period corresponding to the same wave-length is located. This situation is graphically illustrated in Figure 1 where a linear oscillator having a length A is shown.

A dash-line curve shows the current distribution J of the forced oscillations set up by the radiation field, while the dotted curve J, shows the current distribution of the free oscillations arising, e. by virtue of shock excitation. Figure 2 S1OWS a receiving antenna 1 having a length A; the clown-lead dd 467,538, and in Germany July 12,1929.

adapted to conduct the current to the receiver apparatus is coupled in the middle of the antenna. Now, if this antenna is excited by the incoming wave uniformly and under cophasal condition throughout its constituent points, then the distribution of the current will be as indicated in Figure 1 by the dash-line curve J The maximum current which in this instance. has about the same value as in the case of excitation of a dipole as heretofore used having a length half that of the wave, is located in the center of the antenna so that by current coupling at this point it is possible to insure favorable energy supplyto the receiver apparatus.

l/Vhat is possible, on the other hand, by the use of such an antenna, is that the natural wave of the antenna which is excited by shock and whose frequency 1s equal to the frequency of the incoming Wave will not be r fed along to the receiver apparatus. In the dipole antennae as heretofore customarily employed, on the contrary, the current loop of the natural wave corresponding to the frequency of the impressed oscillation lay at the same point as the loop of the impressed oscillation, and the result was that separa tion of the incoming signal oscillations and a stray oscillation set up by shock or otherwise was not feasible.

Indeed, it is only the theoretical consideration and recognition that in the case of an oscillator being equal to the wavelength of the incoming oscillations and which is uniformly excited by the incoming oscillations throughout its entire length, the current crest is located in the center, that has made it feasible to utilize an antenna arrangement as hereinbefore disclosed advantageously for receiving plants.

Using an antenna having a length twice the length of the wave instead of one of simple length, then each half of the. antennae excited by the field presents a current distribution as shown in curve J Figure 1. The current must then be tapped at a distance being one half of the wave. (It will be noted that the current loop is located in the middle of the antenna for the forced oscillations.) An antenna of this kind is illustrated in Figure 3 where antenna 1 is made equal to 2 a, and where the downlead dd is coupled a distance equal to one-half the Wave away from the end of the antenna. It will be understood that this consideration may be extended analogously to includealso longer waves being a whole mutiple of the wavelength. The loops of the forced oscillation will then be located at points being away from the end of the antenna an odd multiple of the half-wave.

Antenna arrangements of the kind here disclosed are suitably used in all installations where heretofore the use of straight antennae has been customary. In order to insure directive effects or a concentration of energy, as will be understood, a plurality of antenna. arrangements as hereinbefore described may be disposed in a curved, say, a parabolic,surfaceor in a plane as well known in the prior art. Antenna arrangements as here disclosed are suitably mounted in planes in vertical or horizontal direction, ashas generally been customary in the art of receiving short waves. In order to make the directional reception unilateral, it is advantageous to employ reflectors in the usual way.

Figure 4 illustrates by way of example an antenna plant comprising a row of oscillators having a length equal to A, being interconnected and associatedwith the receiver apparatus by a joint down-lead or energy leads (Zd. Such an antenna plant, of course,

' may be given any desired direction or orientation in space in a way as has been known in the prior art of antenna arrangements comprising a plurality of individual or constitucnt radiators. lhe most suitable orientation of antennae according to this invention, for the reception of short waves, probably is in horizontal sense at right angles to the line connecting the sending and receiving points inasmuch as this position insures cophasal excitation of the antennae by the incoming radiation field independently of the angle of incidence of the radiations, while in the case of a vertical disposition of the oscillators, cophasal condition will. be secured only when the antenna is positioned at rightangles to the incident radiation, and this will be true only of a definite angle of incidence.

What should be noted finally is that the antennae need not be absolutely equal to one wave-length or a whole multiple thereof; for, in the first place, certain simplifications have been made in the calculations of tie current distribution, while, in the second place it has been found that also in the pres ence of certain detuning the current crests remain at the same point. For instance, if the antenna is slightly longer thank, current nodes will arise for-the forced oscillations at the same distance from the two antenna ends. In the central part of the antenna, that is, between these two nodes the distribution of the current will be similar as in the ideal oscillator case above discussed having a length equal to A.

What I claim is 1. An arrangement for the reception of high frequency oscillations comprising one or more linear conductors each of which in length is equal to the wavelength of the incoming wave or a whole multiple of the incoming Wave length and means for establishing coupling to each of the conductors of the antenna at a distance from one end thereof an odd multiple of half wave lengths of the incoming wave, said antenna being arranged at right angles to the direction of radiation whereby cophasal excitation of the conductors is effected. v

2. A receiving antenna comprising a linear conductor having a length substantially equal to the length of the communication wave and arranged effectively at right-angles to the direction of radiation for excitation substantially uniformly throughout its entire length, and means for establishing coupling tothe antenna at the center thereof.

3. An antenna comprising a linear conductor having a length equal to the length of the communication wave and arranged at right angles to the direction of propagation of the signals for excitation under substantially cophasal conditions throughout its entire length, and means for establishing coupling to the antenna at the center thereof.

4:. An antenna comprising a linear conductor having a length substantially equal to. a whole number of wave lengths of the communication wave, said conductor being arranged at right angles to the direction from which signals are being received, and means for establishing coupling thereto an odd inultiple'of halfwave lengths away from one end of the conductor.

An arrangement for the reception of high frequency oscillations comprising a linear conductor equal in length to the wave length of the incoming wave or a whole inultiple of the incoming wave length, an-

other similar linear conductor parallel to said first conductor, and means for establishing coupling to each of the conductors at a distance from one end thereof an odd multiple of half wave lengths of the incoming wave,

said conductors. being arranged at right angles to the direction of radiation whereby cophasal excitation of the conductors throughout their length is effected."

6. An arrangement according to claim 5 characterized in this, that said conductors are oriented horizontally and disposed at right angles to the line connecting the sending and 7 receiving points.

NICOLAI v KORSHENEWSKY.

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