US2122893A - Conductor for radio frequency currents - Google Patents

Description

July 5, 1938. H. o. ROOSENSTEIN CONDUCTOR FOR RADIO FREQUENCY CURRENTS Filed July 8, 1953 INVENTOR HANS OTTQ RQQSENSTEIN BY /%W ATTORNEY Patented July 5, 1938 PATENT OFFICE CONDUCTOR FOR RADIO FREQUENCY CURRENTS Hans Otto Roosenstein signor to Telefunken lose Telegraphie m. b.

, Berlin, Germany, as- Gesellschaft fiir Draht- 11., Berlin, Germany, a

corporation of Germany Application July 8, 1932, Serial No. 679,505 In Germany August 12, 1932 13 Claims.

This invention relates to high frequency electric conductors and radio aerials.

is useful for various purposes in the high frequency art, and particularly for aerials, to have available, conductors which are in appearance of approximately cylindrical or rod-like form but have the electrical properties of much more complicated electrical structures. The current duct curr distribution over such specially formed conors can be made entirely different from the ent distribution along a simple cylindrical conductor and by employing. such conductors it it possible to obtain in the case of a conductor carrying high frequency energy, special radiation properties, different from those of an ordinary conductor and of an advantageous nature for practical purpose can Moreover, such conductors d to constitute a semi-shielded s. be constructe conductor for high frequency alternating current s and yet be of simple mechanical form.

The various forms of recesses are shown by the accompanying drawing, in. which:

Fig. 1 shows a cross-secti onal View of a solid conductor having recesses at equal distances alon Fi g its length; g. 2 indicates a cross-sectional view of a composite conductor of insulating and conducting material;

g. 3 is another embodiment of a composite conductor tribution of current along the condu g. 3a is a graphic representation of the disctor; while g. 31) is a graphic representation of the distribution of current along the conductor when the outer conductor is the medium for the disdecimeter waves. current distribution on the con A decisive influencing of the ductor occurs if the electrical length of the recesses below the general of magnitude of half the ing frequency. This can surface of the conductor is of the order wave length of the workbe attained while retaining relatively small recesses, by filling in the said recesses completely or par tially with insulating material. The effectiveness of such an arrangement may be still further increased by admixing with the insulating filling material a finely subdivided magnetizable substance, e. g. iron powder.

g. 2 shows in section an arrangement of this kind and in which there is employed a central conducting rod Z over which are pushed structures P, Q and R, consisting of spaced hollow formed tubes, as shown leaving recesses which are completely or partially filled up with insulating material J which may have powdered iron of magnetic material incorporated therein. Such a conductor or lead, consisting as it does of a large number of sections which can be assembled together, has the advantage of being easy to, construct in practice. The properties of such a line when feeding high frequency alternating currents can be continuously varied and adjusted in a very simple manner if the insulating filling material contains a magnetic substance whose permeability is a function of the magnetic field therethrough by passing through the line a variable direct current which produces an adjustable magnetic field in the said magnetic material. In particular, where a conductor as illustrated in Fig. 2 is employed as an aerial (an important application) the. above described method of varying the alternating current properties of the conductor can with advantage be used to vary the radiation diagram of the aerial when used on a given wave length or to obtain a predetermined radiation diagram with different wave lengths. This is of particular advantage where the conductor is employed in a directional aerial system for the linear dimensions of the system can remain unchanged and yet the system can be used over a fairly wide range of wave lengths without substantial deterioration of the directional diagram or characteristic. It will now be explained what form the current distribution or the directional diagram assumes with different lengths for the" recesses of a conductor as shown in the accompanying Fig. 3 when said conductor is employed in a directional transmitting or receivingaerial system. Fig. 3 shows a conductor similar to that of Fig. 2 but with unfilled recesses, i. e. the material J is omitted.

If the electrical length Z of that portion of the recess which lies below the general surface of the conductor is slightly smaller than half the wave length of the working frequency and the length L of conductor between adjacent recesses (see Fig. 3) is slightly larger than the half wave length there is then produced on the aerial a current distribution substantially as shown by the curve K in Fig. 3a. The currents in the lengths between recesses are as will be seen in substantially the same phase at corresponding points in the length of the conductor, so that with such an arrangement sufficiently long relative to the working wave length a sharp concentration of radiation is obtained. A sharp concentration is also obtained if the electrical length of the recesses is made somewhat larger than the half wave length. In this case, the current distribution will be as shown by the curve K of Fig. 3b, and as will be obvious to those skilled in the art, such a current distribution curve is still more favorable for the concentration of radiation. The curves V in Figs. 3a and 3b show the corresponding voltage distributions and it will be seen that there is a voltage node at the middle of each conductor member. In order to avoid losses in terminals, insulators and supports (not shown) for the conductor the said insulators or terminals are preferably fitted at voltage nodal points.

I claim:

1. An antenna for extra short electrical magnetic waves, comprising a rod-like conductor having recesses below the surface of said conductor, said recesses being spaced at not less than onehalf the working wave, said recesses partly filled with insulating material to increase the mechanical strength of said antenna.

2. An antenna for extra short electrical magnetic waves, comprising a rod-like conductor having recesses below the surface of said conductor, said recesses being located at not less than one-half the working wave, said recesses partly filled with insulating material containing a finely divided magnetizable substance.

3. An antenna for extra short electrical magnetic waves, comprising a rod-like conductor hav ing recesses below the surface of said conductor, said recesses being located at not less than onehalf the working wave, said recesses partly filled with insulating material containing a finely divided magnetizable substance, the permeability of the magnetized substance being variable so that the radiation diagram of the antenna and the line impedance for radio frequency currents is variable.

4. An antenna rod-like conductor for radiofrequency currents characterized by recesses which are formed as equally spaced slots in the solid material of said rod-like conductor, said recesses being at right angles to the axis of said conductor and located at not less than one-half of the working wave.

5. A rod-like conductor for short decimeter electrical magnetic waves comprising a conductor having a plurality of rods with annular recesses located on said conductor, said annular recesses being located and spaced apart from each other at one-half the Wave length used on said conductor.

6. A rod-like conductor for short decimeter electrical magnetic waves comprising a conductor having a plurality of tubes of conducting material having annular recesses equally spaced with a plurality of insulating members, said tubes and insulating members being located on said conductor and spaced apart from each other at one-half the wave length used on said conductor.

7. A rod-like conductor for short decimeter electrical magnetic waves comprising a conductor having annular recesses below the surface of said conductor, said annular recesses being located at not less than one-half the wave length used on said conductor, said annular recesses filled with insulating material containing a magnetizable substance, the permeability of the magnetized substance being varied by passing through the conductor a variable direct current which pro duces an adjustable magnetized field in,- said magnetized substance in order that the radiation diagram of the conductor impedance for radio frequency current is variable.

8. A rod-like conductor for high frequency currents having a plurality of annular recesses located at predetermined electrical points on said conductor, said predetermined points being equal to one-half the wave length used on said conductor.

9. A rod-like conductor according to claim 8 comprising insulating members located at voltage nodal points on said conductor.

10. A rod-like conductor for high frequency currents having a plurality of annular recesses located at predetermined electrical points on said conductor, said predetermined points being equal to one-half the wave length used on said conductor, said annular recesses being filled with iron powder.

11. A rod-like conductor for high frequency currents having a central conductor, a plurality of tubular conductors and insulating members alternately arranged on said central conductor, said tubular conductors and insulating members being spaced apart from each other at predetermined electrical points on said central c0nductor.

12. A rod-like conductor for high frequency currents having a central conductor, a plurality of tubular conductors and insulating members alternately arranged on said central conductor, an annular recess on said insulating members, said tubular conductors and insulating members being spaced apart from each other at predetermined electrical points on said central conductor.

13. A rod-like conductor for high frequency currents having a central conductor, a plurality of tubular conductors and insulating members alternately arranged on said central conductor, an annular recess on said insulating members filled with iron powder, said tubular conductors and insulating members being spaced apart from each other at predetermined electrical points on said central conductor.

HANS OTTO ROOSENSTEIN.

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