US2218707A - Antenna array - Google Patents

Description

Oct. 22, 1940. I K FRANZ 2,218,707

ANTENNA ARRAY Filed April '6. 19:58

Fg G 1 ffl-'LECTOR "l effzicrae "c" BEFLL-crae "C" HG. Z.

Zmventor [fu/rt Franz (Ittorneg A vf.; Patented oa. 2z, l1940 L UNITED "sT-ATE ANTENNA ARRAY Kurt' Frnz, Berlin- Charlottenburg, Germany, as-fsignor to Telefunken Gesellschaft fr Drahtlose Telegraphie m. b. H., Berlin, Germany, a cor- M poration of Germanyv Application April 6, 1938, Serial No. 200,370 In Germany February 20, 1937 a claims.

This invention relates to the vmethod vof and 1 ymeans forwreducing the undesired horizontally polarized field comp-onents of a beacon antenna system, and has forits object the provision ofen improved arrangement designedV to reduce the vhorizontal component of the waves radiated from beacon aerials having reflectors by producing an ladditionally radiated compensating Lhorizontal component by inclining or sloping the reector y dipoles.

` v Referring to the drawing, Figure 1 shows a standard beacon arrangement having two reflecr.

4tors;fEigure.2 illustrates how, the standard arrangement is altered in accordance with one ernrbodiment of this invention; and Figure 3 illus.-

{ trates an alternative modification of thisinvention. M

Referring to the drawing, Fig. `1 shows ra standard beacon aerial which comprises a vertical median radiator kA and two reector radiators B and yC which are also mounted in vertical position in symmetric vrelation to A. The entire assembly lis mounted overa horizontal flat metalV 'surface 'D of limitedvdimensionsA as known, for instance, from vehicle antennae and the like. E

is to denote the surface of the earth. If, then the vertical and the horizontal radiation components- `be measured in the direction of the beacon course (median perpendicular to the plane llaid through the radiators), there resultsanundesirable horivf zontally polarized radiation in addition to the desired vertical component due to currents which are induced in the horizontal metal body D of the vehicle. j l v Now, the said horizontal component according d) 'to this invention is compensated by sloping or y inclining the reectors B and C as shown in Fig.

, 2. The inclination of the said two reiiectors is preferably symmetric to the. median radiator, in

other words, in such a way that the two'refiectors, :viewed from the median radiator,y are both inclined either outwardly or inwardly, in a way as illustrated in Figs. 2 and 3, respectively.

' Actual tests made with beam or beaconaerials of this nature have proved that rthe disturbing horizontal component attains a minimum` value for adenite angle of inclination of the reflec-A tors. In fact, the angle of inclination is suitably so chosen thaty the minimum ofthe horizontal component comes to lie inthe horizontal plane and'i'n the direction of the beacon course. Still, it may beadvantageous to keep the minimum un# der a certain angle-of elevation, for instance, for aerial navigation, and this end-is attainable by choosing another angle of inclination for there-y flectors. For instance, an outward angle of inn clination o-f 5 degrees vhas proved suitable.

In the practical applicationof the idea under lying the invention it has proved convenient to mount the reflector radiators pivotally so that readjustment is feasible at any desired time.

I claim as myyinvention: 1. A device of the character described which v -includes a radiating `antenna:mounted substan- -tially perpendicular' to a conducting surface, induced currents in said surface causing undesired )radiation components which are polarized in the plane of said surface,l and a reiiecting antenna Y mountedadjacent said radiating antenna and at that angleto said surface and said radiating anvtennaswhich minimizes said undesired yc oinponents. i 2. A device of the character described which includes a radiating antenna mounted substan-` tially perpendicularV to, and adjacent a conducting surface, means for energizing said antenna to produce a radiation'iield of a desired polarization, said field also causing induced currents to" f flow in said surface, and a pair of reiiecting. an-

tennas mounted at an angle to said surface and y said radiating antenna, ksaid angle being such that a radiation iield is generated having a component polarized in the plane of said surface which'neutralizes the radiation field due to said induced currents. .l I j 3. A device of the character described in claim 2 inv Which.the.angle of said reflecting antenna is such that the radiation ycomponent of said r'eflecting antenna polarized in the plane of said sur-V face is equal and opposite to the radiation comy ponent produced by said induced currents.

KURT

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