US2494198A - Antenna system - Google Patents

Description

Jan. -10, 1950 POSTHUMUS 2,494,198

ANTENNA SYSTEM Filed April 24, 1946 KLASS POSJHUMUS INVENTOR.

AT T ORNFK Patented Jan. 10, 1950 2394498 ANTENNA SYSTEM Klaas Posthumus,

signer, by

Eindhoven, I mesne assignments, to Hartford N etherlanda. as-

National' Bank and Trust .Company, Hartford,

Conn, as'trustee Application April 2.4

vInethe Netherlands, October 2,1942 Section 1, PublioLaw Fatent expires 6 Claims. (01. 25033.51.

In an antenna system comprising a conductor wherein solely travelling waves may appear, it is known that this conductor can be replaced, for avoiding the losses occurring in the necessary terminating resistance, by two juxtaposed parallel conductors which are arranged at a small distance from each other, say Ta orless of the operating wave length, and are excited in such manner that stationary waves displaced in phase by 90 appear in them.

The present invention has for its object. toprovide an extremely suitable method of connecting and arranging the feed conductors in an antenna system comprising such a pair of-cond-uctors.

According to the invention, one conductor of the pair of conductors is interrupted atsa current loop, which occurs at a point preferably midway the ends, and the connecting terminals thus formed are respectively connected to the conductors of a twin-core feed line, the other conductor being connected to a single-core feed conductor at the voltage loop which occurs at the point corresponding to the point of interruption.

In order to avoid radiation coupling between the two feed systems preferably the single-core feed conductor is provided midway between the conductors of the twin-core feed line.

The invention will be more fully explained by reference to the accompanying drawing representing, by way of example, an antenna system according thereto.

In the sole figure the reference number designates a half-rhomb antenna located in a horizontal plane for the emission of oscillations to be transmitted mainly in the horizontal direction indicated by the arrow 2. The antenna is composed, in a manner known per se, of two juxtaposed parallel conductors 3, 3' and i, 4 which are arranged at a small distance from each other so that they are strongly coupled by radiation. The conductors 3, 3' and t, 4', each of which has a length of say 4i \=operating wave length) should be excited in such manner that stationary waves displaced in phase by 90 appear therein.

The ends of the conductor 3, 3', in contradistinction to those of the conductor 4, 4, are earthed so that, since the length of the conductors is a whole multiple of the operating wave length, a current loop occurs at the middle of the conductor 3, 3, whereas a voltage loop occurs at the middle of the conductor 6, 4'.

The conductor 3, 3' is interrupted at the middle where it is connected to a feed line 5 consisting of two conductors, while the middle of the 690-, AuguSt8,'-'1946 umber-2,1396% conductor 6 areinductwel-y coupled, with coils 8 and 9 respectively which are connected to a transmitter 1 a displaced in phase by In thisway the conductor halves '3 andt fed in push-pull, whereas the .4 and 3- are fed in parallel with a phase displacementofeo with respecttothe conductor halves 3 and 3'.

-What-.L claim. is

1. An antenna system comprising first and second radiating conductors: juxtaposed in par allel rel-ationtand, having respective lengths substantially equal to a whole multiple of the operating wave-length of the antenna system, said mediate wire of said line being connected to the midpoint of said second conductor.

2. An antenna system comprising first and second radiating conductors juxtaposed in parmeans for applying voltages displaced in phase line, and means for and a transmission line for feeding said conuctors, said line being formed by three equispaced parallel wires, the outer wires of said line {being connected to said input terminals and the center wire being connected to the midpoint of said second conducto .7

4. An antenna system comprising first and second radiating conductors juxtaposed in par spaced parallel wires, the outer wires of said line I being connected to said input terminals and the center wire being connected to the midpoint of f for applying radio said second conductor, means frequency voltages of a predetermined wavelength and displaced 180' in phase from each other to the two outer wires of said line, and means for applying a radio frequency voltage of said wavelength and displaced 90 in phase from the voltages in the outer wires to the center wire of said line.

5. An antenna system adapted to be energized from a source of high frequency voltage having a predetermined wavelength, said system comprising first and second radiating conductors juxtaposed in parallel relation each having a total length substantially equal to a whole multiple of the operating wavelength of said system, said first conductor being divided at the midpoint thereof to provide input terminals thereto, said first conductor being directly grounded at the extremes thereof, a transmission line for feeding said conductors, said lines being formed by three parallel wires, the two outer wires of said line being connected to said input terminals and the intermediate wire being connected to the midpoint of said second conductor, a first transformer having a primary connected to the voltage source and a centertapped secondary whose ends are connected to said outer wires and whose centertap is grounded, and asecond transformer having a primary connected to the voltage source and a secondari having one end thereof connected to said intermediate wire and the other end thereof grounded.

6. An antenna system as set forth in claim 5 wherein the axes of said first and second parallel conductors are arranged in an oblique angle whose apex is the midpoints thereof whereby said conductors form a half-rhombic antenna.

KLAAS POSTHUMUS.

REFERENCES CITED The following references are of record in the

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