US2189910A - Antenna arrangement - Google Patents

Description

Feb. 13, 1940. E. KRAMAR- ANTENNA ARRANGEMENT Filed Nov. 2, 1937 ffz Ven Z901", f /ws /1 ramar by KfW Pariah-13,1949 2,189,91@

j y2,189,9101` l ANTENNARRANGEMENT? 12,; f Ernst Kramar, Berlin-Tempelhof; 'Germany'gjas" signor to(llorenzAktiengesellschaft;Berlin' s TempelhofifGermany, a company f t t@ Application November 2, IKQSLSriaIi/o. 17y y I In Germany August 25, 1936 4 claims. (ol. 25o-11) The present invention relates to antenna arof the main'radiatorI-I and of thereflectors Rl rangements and has for its object to avoid radiaand R2 is equal to M4. The radiator and. the tion of undesired horizontal components. reflectors are tunedwith respect to ground. The

Rotatable antenna arrangements in which a connection to ground E may comprise a highly 5 continuous dash line is caused to rotate in order conductive surface of plaited meshwork', for into create direction finding, are well known in the stance. It has been found in connection with art. Means are thereby provided for determining antenna arrangements operatingtwith vertical M 4 the elapse of time between the transmission of an antennae and M4 reflectors, that not only verundirectional signal and the receipt of the contically polarized waves are radiated as theoretiil) tnuous dash line. The undirectional signal may cally expected, but also a very essential portion of be transmitted when the continuous dash line horizontal components.. The occurrence of the passes through north, for example. It is well horizontalcomponent may be explained in such known in such cases to employ an antenna ara manner, that the counterpoise structure itselfy is rangement having a permanently supplied radiaexcited to oscillations by virtue of the balancing i5 tor, the radiation characteristic of which is alteror equalizing currents represented by the dotted 15 nately displaced by means of two keyed antennae line i, these equaliZing Currents loW between the whichvact as reectors. The antennae effecting individual radiators over the earth surface comthe displacement of the main antenna radiation mon thereto, whereby radiation with horizontal characteristic are alternately keyed in any known characteristic is Produced.

-0 manner, so as to obtain a continuous dash line. In Order t0 overcome this disadvantage,y the 20 In cases when it seems desirable to reduce the present invention provides one separate countersize of an antenna system, the thought .may arise poise structure for each individualr radiator, kas to use dipoles having a length equal to M4, instead illustrated in Fig.` `2- t A `circular yoounterlooise of dipoles of M2 length, and to tune the former structure is located below the main radiator I-I` dipo1es to earth or to a counterpoise structure.l and is completely Separated from-the Counterpoise 25 Investigations have proved that such antenna Structures allotted to the reflectors Rl and R2. A i arrangements permit perfect radiation to be oblOW of `currents having an horizontal component tained under such circumstances only, that the is tlierebi7 eiectivelv avoided. v counterpoise structure has a certain magnitude, It is readily obvious that the circular shape of v l as reliable and symmetric radiation conditions will the counterpoise structures shOWn in Fig- 2 is not 30 otherwise not be secured. However, several diinecessarily required, but that an elongated culties are introduced on reanzing the necessary Counterpoise Structure having arcuated ends may measures, which are obviated according to the be employed and subdivided bv slOtS 0r the like. invention. Although in special importance infconnection According to one feature of the present inven- With rotatable antenna arrangements as. above 35 tion, each radiator of an antenna arrangement is described and demonstrated merely bv Way of equipped with a separate counterpoise structure, an eXarnDle, the inventive idea is' by no means so as to avoid radiation of an undesired horizontal limited to this type, but is applicable in Similar component. A manner also to fixed systems, not'only toar- 4o The inventive idee of the present application rangements 0f the radio beacon type as men- 40 wiilmore readily be understood from the renewing toned above, in which reflectors are adapted description in conjunction with the attached t0 Cooperate With a radiator, but even t0 lall drawing, in which multi-antenna arrangements (radiation trans- Fig. l diagrammatically illustrates an arrangemiti/ing and receiving Systems), in Which the ment according to a known antenna system, While suppression of the horizontal component is de? 45 Fig. 2 shows a diagrammatical representation sirable. i of an improved antenna arrangement according Furthermore, the invention is also applicable to the invention. in connection with a new proposition according The known antenna system in Fig,- l shows va, to which the antenna structure is rotated merely 5o main antennaHbeing supplied fromatransmitter with respect to va portOn 0f the counterpoise 50 S. If the antenna arrangement is employed for structure, The .rotating part of the antenna receiving purposes, the main antenna is associated structure is thereby capacitively coupledy to a with a receiver. ,Two reflectors, RI and R2 are larger xed counterpoise structure. `The latter provided and alternately keyed at their lower must be sub-divided according tothe invention,

ends by means of contactsrl and r2. The length so as toobtain oneindividual counterpoise strucy ture allotted "to each radiator. In realizing this idea, the rotation must be effected with respect to an eccentric axis. It is especially suitable in this case to make the capacity between the fixed and the rotating portions ofthe counterpoise 'structure smaller than the intrinsic or space capacity of the rotating system.l

1. A direction Iiindilng, antenna system'comprising a plurality of individual radiators, and a plurality of metal counterpoise-ground struc tures, each of said counterpoise structures being individually allotted to a corresponding radiator,

the counterpoise structures being entirely sepavL rated from each other whereby radiation of undesired horizontal components is avoided.

2. A direction finding antenna system accord- -fbeing tuned to one-half wave lengths together with the associated individual counterpoises.

4. A direction nding antenna system according toclaim 1, in which the radiator is rotatable with respect to a portion of its associated coun- 15 yterpoise-ground structure.

l ERNST KRAMAR.

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