US 2283081 A
Description (OCR text may contain errors)
May 12, 1942- E. METscHl.
DIRECTIONAL ANTENNA Filed Nov. 9, 1939 Patented May 12, 1942 NITED STATES DIRECTINAL ANTENNA Application November 9, 1939, Serial No. 303,520
Directional antennae intended for very short waves, such as ultra short Waves and decirneter waves, are known which are composed of a number of dipoles arranged in line to constitute a single antenna.
The invention relates to antenna structures of the kind comprising a number of antennae composed in this way, and it is mainly concerned with the provision of means by which these antennae are secured together.
In the accompanying drawing, Fig. 1 is a dagrammatic perspective view of an antenna of known type, Fig. 2 is a diagrammatic perspective view which shows one embodiment of the invention, Fig. 3 is a plan view of the arrangement represented in Fig. 2.
Fig. 1 shows tubular dipoles I, 2, 3, 4 arranged in line and containing conductors 5, 6, l, 8. These conductors and dipoles are interconnected alternately, that is to say, conductor 5 is joined to dipole 2, conductor 6 joined to the dipoles I, 3, conductor 1 joined to the dipoles 2, 4, while conductor 8 is -connected to dipole 3. The dipoles are each half a wavelength long. The distribution of potentials is represented by curves 9, I0,
II, I2 which show that there is a potential node in the middle of each dipole. With such an antenna positioned vertically the directive diagram thereof is circular in the horizontal plane while in the vertical plane a sharp concentration of the lines of force is effected by the antenna being:
excited in harmonics.
In order to obtain an additional directive effect it will be necessary t0 employ a number of antennae of the kind represented in Fig. 1. These antennae have to be arranged aside each other and at predetermined distances apart while -re- 'quiring to be interrelated by certain phase conditions. All these antennae may be fed, but it is possible also to feed only one antenna, the other ermany November 9, 1938 (-Cl. Z50-33) held in position by braces I9, 20, 2|, 22,'xed at the potential nodes of the dipoles I, 2, 3, 4 of which each antenna is composed.
In this Way an antenna system of mechanic uniformity can be constructed with the .aid of simple means. It is not necessary to have the braces I9, 20, 2l, 22 made of high-grade insulating material. Inferior insulating material may be used instead or the braces may be made of metal. For instance, they may be cast members. As the braces are fixed at the potential nodes no currents will ow between the antennae I3, I4, I5, I6.
Systems as provided by the invention may comprise any suitable number of antennae and these may `consist of any suitable number of dipoles. It is immaterialalso whether they are fed or are arranged to act as mere reflectors. Furthermore, the novel arrangement is adapted to serve either for transmitting or for receiving. Moreover, the invention is not restricted to the use of component dipoles of the kind/comprising inner conductors and tubular outer conductors interconnected at their joints. However, it is necessary for the voltage distribution to be such that there are potential nodes at which the said braces are fastened to the dipoles. The antenna system as a whole may be positioned vertically or horizontally. Preferably, it is arranged as a freely supported structure.
What is claimed is A rigid unitary antenna structure for shorty Y and horizontal spacingy of all the dipoles is per-4 manently maintained. Y e