US2334279A - Antenna construction - Google Patents

Description

Nov; 16, 1943. M. s. NEIMAN ANTENNA CONSTRUCTION Fled May 7', 1940 INVENTOR. /77//f/7? J. Nfl/HIV BY 7% ATTORNEY.

at several' points. j

Patented Nov. 16, 1943 N ED S A E PATE-NT o==-=cE- ANTENNA CONSTRUGTIDN i Mikhail Samoilovich Neiman Leni grad; Union i ofSoviet Socialist Republics, assig'nor to Radio Corporation of America, a Corporation of Delai a Ware u Application May 7; 194o, Seria;ll`lo.`3 33, 846; inj i Union' of Soviet Socialist Repblics March-';

This invention "relates to a new and useful antenna Construction. p 4. j

An object of this i'nvertion` is to provide a 'system to jfe'ed energy at any point on the antenna by a shielded `feeder terminating in 'the form; of a coupling device, which 'may provide either magnetic or oapacitiv coupling.

Another object of this invention is to `rr ajsure the antenna energy at any point and to Obtain anti-fading or general directive `qualities` in a vertical'plane with an'antenna much reduce'din height by comparison 'with the wave length and also to 'obtain an optionalldistribution in phase and amplitude for the currents 'in the antenna "so as"to secure the most favorable radiation diagram.

Another object energy at. any point to obtain a periodic, cortinuous or 'automatic check of,the distribution of Currents in' various parts` of the antenna, or

of this invention is to measure i to provide signals indicating deviations from the normal. i

i A further object of this invention isto eiectively tune the antenna from the transmitter building. p 4 v 4 V U A still further object' of this inyentionisto tune the upper antennaelements to control" the distribution lof currents `from ground or from the transmitter building. V A still'further object of this invention'is to provide means for fe'eding energy to thean'tenna some' jo:` the ;man-y other 'objects of this fin vention are 'to' provide an antenna system to 'eliminate the' ha'rm'ful effect ofgtravelingwaves along the antenna mast and to widen the frei quency band of anti-fading antenn'a's, as well as otherantennas, also, to provide an 'anti fading antenna suitable for operation on' a certain wave range. n i

In order to attain these bbjects, Ipro'pose an antenna' the .Construction of which can be most panyingdrawing,` in which:

readily understood by referr'ing to theaccom- Fig. 1- shows one form of antenna construci.

tion of; thisinvention; v

Fig. 2 isia diagram showing the electro magnetic oscillations inthe antenna `Fig. 3 is another modification of the' invention wherein the "antenna is tuned from the ground: Fig. 4` is another modificationoi the invention showing asingle turn coupling coil:

Fig. 5 is another modification of'the invention showing a toroid 'shaped coil; and

-` Fig; 6 is another *modification of 'the invention shwing a measuring method;

'f 'Referring now in detail to'Fig. `1 'of the drawin'g,` I `*is the verticalmast or -tower of the'an tenna, 2`a shielded feeder' whichincludes two insulated leadsand which runs from an oscilla-` tion source *l at 'first on the ground'and then along the mast, the leads then tern'iinating at a certain 'height'` in a`coi1f3 made up of one or several turns dr windings of any 'desired shape. The preferred position of the axis of the col is horizontal to" and at ninety degrees with respect to the axis of the antenna.

Theiexterior `'surface of the metallio shielded feeder 2` is attached without any 'insulation directly to the metal of the'antenna' mast, thus constituting, in" an electrical sense, a common b'ody.- "Asiar as 'the inner' part of the shielded feede r" is concerndg it is notelectrically connected withthe antenna proper except for the nagnetic coupling' 'which is *effected by the coil 3.3 'I'hisconstitutes the useful coupling which canbeutilized'in two wayszior example, on one hand by having the radio irequency-generator connected to the lower end of the 'feeder which will produce in the anter'na electro-magnetic' oscillat'ions asja'. result' of the coupling (which may be if` 'desired 'either inductive or capacitive) between the coil and the structure of the tower. Thus, a possibility of feeding the antenna is provided. As shown by Fig. 2, the action of the generator may in this case be replaced by an equivalent electromotive force ap' plied at the point where the coil 3 is located.

On the other hand, if the antenna is fed by some other electro-motive force, one may con- `'rrect to theldwer e'nd of the feeder 2 ameasuring instrument 1; for instance; an amm'eter, whichfcould be'u'tilized tomeasure 'the' instantaneo's' 'current in theante'nna at the' point where' the 'coil -6 is located, i. e., at'any height *above the gr'ound, as 'shownby Fig. 3.

arrang ed in any manner-de'sired along the antenr'a The amplitudes and phases of these electrombtive' forces may` also be fixed at random by means of suitably selected coupling elements. 'All 'feeders may be supplied either by a single 'generator or by several generators. Furthermore, itis evident 'that the current could bemeasured at any number' of points along the antenna, which {makes it possible to have at 'hand in the transdesired radiation diagram (for instance, one markedly fiattened toward the horizon) with an 'Under' such conditions, it becomes possible to obtain any antenna of any height. Obviously, a reduction in height of the antenna renders the actual construction of such an antenna more difiicult inasmuch as the number and intensity of the electromotive forces'must increase accordingly. Therefore, practical considerations impose certain limits in this respect. However, by comparison with ordinary antenna types, the proposed construction oflers certain decided advantages regarding both the reduction in height of the antenna and the effectiveness of the radiation diagram.

We observe further that by a proper selection of the coupling elements between the generator and the coils located at different heights along the antenna, .it is possible to obtain relatively difierent changes in the amplitude and phase of these electromotive forces for any change in frequency of the generator. This fact can be utilized to extend the frequency band of the antenna or to improve the frequency characteristics.

It is necessary to point out also that this invention enables the operator to tune the antenna from the ground. For a better understanding of this feature, let us refer to Fig. 3. Here, 5 is a coil which feeds the antenna, 6 is a coil supplying a certain electromotive force e. If we make the phase of the current I in the coil 6 such that the electromotive force eis in a, phase quadrature relationship with the antenna current IA at the point of location of the coil 6, then the efiect of this electromotive; force is equivalent to providing at this point an inductance L in series, given by Therefore, by varying the amplitude of the current I in the coil by changing, for instance, in the transmitter building the coupling between the feeder that supplies it and the generator, we are able to change the value of `the equivalent inductance provided in the upper part of the antenna. -Thus, the changing of this inductance, i. e., the tuning of the antenna, may be accomplished from the ground.

This feature also makes it possible to utilize anantenna for any wave within the wave range without the necessity of climbing the antenna every time the length of the' Operating wave is changed.

Obviously; this invention is applicable not only e to tower antennas but to any other type of antennas, for instance wireor hollow-pipe antennas. Likewlse, due to the reciprocal principle,

this invention is equally appllcable to receiving e antennas, only that in this case, the coupling way of common shielded feeders.

elements to the generator are replaced with corresponding coupling elements to the receiver and with proper phasing elements.

Let us note, furthermore, that in some cases (for instance in the case of wire antennas) it may. prove more convenient to couple the coils at the ends of the feeders, not to the straight antenna wire or to the body of the tower but to an additional coil in series with the antenna wire. Moreover, for the purpose of reducing the number of shielded feeders required, it is feasible to secure the 'coupling between the transmitter or reeiver on one hand and all the coupling coils or a group of these coils on the otherhand by In this case, the shielded feeder must extend to the most disv tant coil (for instance, the highest), while at the location of the other coils the feeder is tapped (parallel, in series or in some other way).

similarly, when vacuum tube voltmeters or rectifiers such as 9 are used in measuring the current, the wires connecting the various meters may be combined into a common shield or cable. The return wires may also be combined.

The coupling coils may be of various construction. They may be built in the form of singleturn IU as shown by Fig. 4 or multiple-turn loops attached directly to the tower or mast.

One may also apply, though this is not likely to be necessary in the majority of cases, various electrostatic shields (for instance, in the shape of a split pipe shield concentric with the coupling coil). As shown by Fig. 5, a convenient shape of coil ll may be a toroid surrounding the antenna. conductor.

Now, in addition to the foregoing, let us consider another method of eedlng the antenna. If the main conductor of the antenna is provided with a branch (for instance, in the shape of a horizontal wire), then by coupling the' coil at the end of the feeder to this wire, we obtain another coupling, in the manner explained above. In the main conductor of the antenna, there will then be a drop in current, not in voltage, as a result of the current defiected into the branch. As shown by Fig. 6, one lead I2 is conductively connected to the mast l of the antenna tower and the other lead !3 left free theretrom. If the lower end of the feeder is connected to a measuring instrument,` instead of being connected to the generator, the meter l4 will register the voltage in the antenna, not the current. Thus, it becomes possible to measure both the current and the voltage at any point along the antenna.

What is claimed is: i

1. An antenna system comprising an antenna member electrically 'connected to ground at the base portion thereof, a plurality of metallic shielding members located at the base portion and arranged so as to follow up along a portion of the sides of said antenna member and electrically connected thereto, a pair of insulated leads located within each 'one of said metallic shielding members, a plurality ofcoupling coils, each coil located near the upper' and open end of said metallic shielding'members and' inductively coupled to said antenna member at a voltage node, each of said leads connected at one end to said coupling coils and' at the other end to a transmitting source of energy, and measuring means for measuring the transmitting 'energy at several points along the antenna member.

2. An antenna' system comprising .an antenna member electrically connected to ground at the base portion thereof, a plurality of metallic shielding members located at the base portion and arranged so as to follow up along a portion of the sides of said antenna member and electrically connected thereto, a pair of insulated leads located within each one of said metallic shielding members, a plurality of coupling coils, each coil located near the upper open end of said metallic shielding members and inductively coupled to said antenna member at a voltage node, each of said leads connected at one end to said coupling coils and at the other end to a transmitting source of energy, and means for tuning the antenna from the point of source of the transmitting energy. 4

3. An antenna system comprising an antenna member electrically connected to ground at the base portion thereof, a plurality of metallic shielding members located at the base portion and arranged so as to follow up along a portion of the sides of said antenna member and electrically connected thereto, a pair of insulated leads located within each one of said metallic shielding members, a plurality of coupling coils, each coil located near the upper open end of said metallic shielding members and inductively coupled -to said antenna member at a voltage node, each of said leads connected at one end to said coupling coils and at the other end to a transmitting source of energy, and. means for tuning theantenna by having the Voltage out of phase at diflerent lengths of leads to said antenna coupling coils.

4. A radio frequency system comprising a radiating member electrically connected to ground at the base portion thereof, a plurality of shielding members located at the base portion and arranged to follow up along a portion of the side of said radiating member and electrically connected directly thereto, at least one insulated lead located within each one of said shielding members, each shielding member having an open end located at different levels above ground, a coupling element located near the upper end of each one of said shielding members,` each coupling element coupled to said radiating member, each one of said insulated leads arranged in circuit connection with said coupling element and said radio frquency 'device whereby optional distribution in phase and amplitude for the currents in said radiating member is obtained to secure the most favorable radiation diagram. p

5. A radio frequency system comprising a radiating member electrically connected to ground at the base portion thereof, a plurality of shielding members located at the base portion and arranged to follow up along a portion of the side of said radiating member and electrically connected directly thereto, at least one insulated lead located within each one of said shielding members, each shielding member having an open end located at different levels above ground, coupling means located near the upper end of each one of said shielding members for obtaining a desired distribution of current in said radiating member, each coupling element arranged for electrically coupling to said radiating member, each one of said insulating leads ,arranged in circuit connection with said coupling element and a radio frequency device whereby optional distribution in phase and amplitude for the currents in said radiating member .is obtained to secure the most favorable radiation diagram.

6. A radio frequency system comprising a radiating member electrically connected to ground at the base portion thereof, a plurality of shielding members located at the base portion and arranged to follow up along a portion of the side of said radiating member and electrically connected directly thereto, at least one insulated lead located within each one of said shielding members, each shielding member having an open end located at different levels above ground, coupling means located near the open end of each one of said shielding members for obtaining a desired distribution of current in said radiating member, each coupling element arranged for electrically coupling to said radiating member, each one of said insulating leads being arranged in circuit connection With said coupling element and radio frequency device, and rectifying means located adjacent the open end of at least one of said shielding members and connected to at least one of the insulated leads contained within said shielding members.

MIKHAIL SMOILOVICH NEIMAN.

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