US1773097A - Staggered-wave antenna system - Google Patents

Description

Aug; 19, T930. s. w. DEAN 1,773,097

` STGGERED WAVE ANTENNA SYSTEM Filed March 3, 1 92'7 2 Sheets-Shert l INVENToR. 5. Wem/U ATTORNEY Receiver Allg. 19, 1930. s W DEAN 1,773,097

STAGGERED WAVE ANTENNA SYSTEM 'ective (larve fm' :l1/wle .system IN V EN TOR.

BY Zing/i ATTORNEYS.

Patented Aug. 19, 1930 UNTTED STATES PATENT OFFICE SAMUEL W. DEAN, F HOULTON, MAINE, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPI-I COMPANY, A CORIORATIONOF NEW YORK STAGGEREDWVAVE Application led March 3,

This invention relates to a staggered wave antenna system and particularly to' a system in which the conductors constituting the separate antennae of the staggered system may be placed upon vthe same pole line without introducing crosstalk or other interterk ence effects.

The wave antenna of the type described by Beverage et al. in the Journal of AAmerican Institute of Electrical Engineers, Vol. XLII,

Nos. 3k to 6, inclusive, comprises a single conductor of considerable length relative to the length oi the wave that the said antenna is intended to receive. Vhile such an antenna has a good directional characteristic, it is not entirely devoid of receptional ability at 180 degrees from the desired direction ot reception. This failure to entirely eliminate waves arriving from an undesired direction somewhat diminishes its value. It has been found that reception at 180 degrees may be substantially suppressed by combining the signals received by a plurality of wave antennae, which are not only parallel but also are staggered. By staggering is meant that the initial ends ot the wave antennae are in a plane that is not parallel to the wave front of the waves desired to be received but makes an angle with the wave front. Such an antenna svstem has been characterized as astaggered wave antenna system and by properly proportioning the parallel antennae and the extent of the staggering, the system has a di'- rectional characteristic in which reception at 180 degrees from the desired direction is practically eliminated. Similar Yresults have been obtained by the system disclosed inthe co-pending application of A. G. Chapman,

40 Serial No. 130,637, tiled August 2l, 1926. One of the diliiculties in the systems of the prior art set forth above is that the plurality of antennae constituting the system cannot be placed upon the same pole line, because crosstalk and other interference effects will be created between the various antennae of the system.

My invention resides in a staggered wave antenna system in which the several antennae,

upon which the system is based, may all be ANTENNA SYSTEM 1927. Serial No. 172,448.

placed upon the same pole line without creating crosstalk or other interference effects.

Another object of the invention resides in the employment of the sections of the antenna system not only to pick up signals from the electromagnetic waves but also to serve as connecting circuits between adjacent sections ot the antennae, whereby the currents set up in the adjacent sections may be carried to and properly combined at the receiving apparatus connected with the antenna system.

Another object of this invention resides in the use ot a four-wire phantom system in Awhich the invention is embodied, having means whereby the receiving apparatus may be placed at the end of the system upon which the desired signal waves lirst i-mpinge and means by which the signals may be returned from the distant end of the antenna system to the said receiving apparatus.

Other objects of this invention will be apparent from the following descrlption when read in connection with the attached drawing of which Figure 1 shows schematically a wave antenna of the typeydisclosed by Beverage et al.; Figs. 2 and Sshow thesectionalizing of the wave antenna. and means for transmittingvthe currents from the various section to the receiving apparatus at kthe remote end thereof; Figs. land 5 show the combining `of a plurality of sectionalized wave antennae and means for propagating and combining in the correct Way the currents from the various' sections; Figs. 6 and 7 illustrate the description of the invention; Figs. 8 and 9 show the meansfor bringing bacl, from the remote end of :the antenna system, the currents set up in the various sections of the antenna and combining them in the receiving` apparatus at the initial end of the, said system; and Figs. 10 and 11 are curves plotted to rectangular co-ordinates showing the directional characteristic of the antenna system.

The wave antennaof the type described by Beverage et al., which is shown in its simplest form in Fig. l, has a directional characteristic, depending upon its length and other factors such as is'disclosed in the paper pubwas Y ceiver R. The

lished b Beverage et al. in the said Journal,

Vol XL I, No. 4. As will be seen from those directional characteristics, such an antenna has a varyin amount of receptional ability throughout the range extending from 90 degrecs. to1270 degreesfrom the desired direction ot reception.

I have found that an antenna of the type shown in Fig. 1y may be broken up into a plurality of sections such as shown in Fig. 2 which sections are preferably of equal length, and by omitting the alternate sections and combining the currents set up in the respective sections, the directional characteristic will be substantially that of the antenna shown in Fig. 1. The currents from the variouasecti'ons may be transmittedto the receiver in the manner shown in Fig. 3. As showntherein, sections 1, 3, 5 and 7 are connected by the transmission circuits 2, 4 and 6. The connection between the circuits and the unit antennae is effected by means of the transformers such as T1 to T8, inclusive. The unit antenna. 7 is connected-with the receiving apparatua R by the transformer T7. It will be apparent, that the current set up in the antenna 1 by the wave advancing in the direction indicated by the 'arrow will be impressed bythe transformer T1, upon the metallic circuit 2, over which it will travel to the antenna 3, upon which it will be impressed by the transformer T2. This current from antenna 1 will travel over antenna 3 as a grounded circuit. There will also be set up, in antenna 3, a. current resulting from the impinging of the electromagnetic wave thereon. These twocurrents will be impressed by the transformerdfla u ln the metallic circuit 4 and in `turn, upon t eunitantenna 5 which const-itutes` a grounded circuit for the transmission of thmcurrents from the antennae 1 and 3. The current set up in antenna 5, by the advending"4 gwave, together with the currents from the other antennae, will be transmitted over thecircuit 6 to the antenna 7 and these currents together with that created in antenna 7 the advancing wave, will be impressed bythe transformer T7 upon the reprinciple shown may be applied to any desired number of sections, the .number shown inthe drawing being chosen .simply toillustrate the case and not constitutin'ge'limitation thereon. Since the currents generated in .the various unit antennae are ated over'the metallic. circuits, such as free...

EA: 6, to the Initial ends of the succeedmg `unit'. antennae with nearly the same velocity est .,wouldif the antenna were continuous, nch.asystem, thereforershould have a direcional Vcharacteristic not greatly different from `that which wouldbe obtained from a continuous antenna such asshown in Fig.v 1. sois clearffrom the calculations lemme-@awed f l @when resides@ Part, in

the lines 3 and 5.

the superposition upon a wave antenna comp rising a plurality of unit antennae such as is disclosed 1n Fig. 2; another similar wave antenna, likewise comprising a plurality of unit antennae, in such manner that the active antenna sections of each system occupy upon the pole line the spaces or intervals between the sections ofthe other wave antenna. This idea is shown in Fig. 4, wherein the solid lines rc present the unit antennae and the dotted lines represent a transmission circuit, connecting adjacent unit antennae of the system. As will be seen from Fig. 4, the unit antennae 1, 3 and 5 are sections ofvone of the basic wave antennae, the sections being connected by the transmission lines 2', 4' and 6. Similarly, the unit antennae 2, 4 and 6 are sections of another basic wave antenna displaced longitudinally by the distance 1 with respect to the basic antenna of which sections 1, 3 and 5 are units. These unit antennae are connected by Since there is no parallelism between any two unit antennae, there will be no crosstalk between the component wave antennae, and, consequently, the interw ference, which heretofore has prevented the placing of the conductors of separate antennae upon the same pole line, has been eliminated. The use of separate, parallel conductors such as 2 and 2', one for picking up the wave and the other for the transmission of currents between sections is, of course, undesirable from the cost standpoint. Also, such conductors might have an undesirable effec-t on the characteristics of the antenna unless they are made an integral part thereof. This parallelism may be avoided by making the conductors that serve as active antenna units Vfor one of the basic antennae serve also as the transmission circuit between units of the other basic antenna. Such an arrangement is shown in Fig. 5. It involves a pair of conductors u on a pole line, which pair is sectionalized ut rendered continuous electrically through a plurality of transformers spaced apart at such distance as to provide preferably equal lengths of conductors between them. As shown in the figure, the pair impedance 9. The primary winding of transle.

former T9 is connected across the other end of the pair constituting section 2, and the midpoint of this winding is connected with one side of the primary winding of transformer T10, the other side of which is ground- .l

lUfi

lin

Votherside being grounded. lof T1.1 is connected with the receiver R. As

tromotive force in each.

ed. The secondary winding of transformer T has one end grounded and theother end connected with the midpoint of the secondary of T10, which is bridged across the conductors of section 3. Transformers T11 and T12 are connected with sections 3 and 4 in the same manner as transformers T0 and T10 are with sections 2 and 3. T he primary winding of transformer T13 is connected across the other end of section 4 and the secondary of this winding is connected with the receiver R. `The midpoint of the primary of transformer T13 is connected with one side of the primary winding of transformer T11, the The secondary the wave representing the desired signal strikes 'the section 1 of the antenna system, it will cause current to flow over the two cond-uctors in parallel to ground, through the primary winding of the transformer T5 and through the impedance 3. This will induce a voltage across the secondary winding of TS which will cause the circulation of current over these two conductors in series. This current flowing through the primary of the transformer T9 will induce a voltage across the secondary winding thereof which will cause the liow of current over a circuit which includes the two conductors of section 3 in parallel, to ground through the primary winding of transformer T11.V rThe flow of current through the primary of transformer T12 will induce a voltage across its secondary, which will cause the flow of current over the VConductors in series and the primary of transformer T10. This will in turn cause current to flow through theV circuit connected with the secondary of this transformer, which circuit is connected with Ithe receiver Tt will be seen that the current, generated by the electromagnetic wave upon the unit antenna 1, is conveyed over sections 2 and 4 metallically and over section l3 as a grounded cir cuit. Thile this current is being transmitted, as described, the wave will also travel over , sections 2, 3 and 4 and produce an elec- Tt is evident that the currents in each basic antenna which constitutes one-half of the system traverse 'alternately grounded and metallic circuits and it is obvious that this principle can be extended to any desired number of sections. While traveling along the grounded circuits, the currents receive increments from the electromotive forces due to the signal waves in space,

receiving station is at the end of the antenna remote from the end upon which the desired signal strikes the antenna in the course of its travel from the transmitting station. It is sometimes desirable to have the receiving station at the same end of the antenna which the wave first strikes in the course ofits travel. It therefore becomes necessary to 4bring back to the receiving station the currents from the end of the antenna remote from the receiving station. An arrangement for doing this is set forth in Fig. 8.

In the figure, the receiver R is connected by the transformers T1.1 and T with two pairs of conductors broken into sections by transformers which are so connected as to provide metallic or grounded phantom circuits for the picking up of the signal and the propagation to the receiver R of the currents resulting therefrom. The transformer T14 connects the receiver with section 1 of one pair of conductors and transformer T15 similarly connects the receiver with section 1 `of the other pair. The midpoints of the windings of these transformers connected with sections 1 and 1', respectively, are connected to ground through a suitable resistance 10. Sections 1 and 1 are connected with sections 2 and 2, respectively, by the transformers T1 and T1, respectively. The midpoints of the windings 11 and 12 of T1 and T1, respectively, are both connected with one of the terminals of winding 13 of transformer T0, the other terminal of which' is connected to ground. The midpoint of 'winding 14 of transformer T1 is connected with one terminal of winding 15 of transformer T0. Winding" 16 of transformer T.1 is connected with the other terminal of winding 15, the midpoint of which is connected' to ground through a suitable resistance 36. Sections 2 and 2 `are connected with sections 3 and 3', respectively, by the transformers T2 and T5, respectively. The midpoint of winding 17 of T1 is connected with one terminal of winding 18 of transformer T10 and in like manner the midpoint of winding 19 of T5 is connected with the other terminal of winding 18. The midpoint of winding 18 is connected with one terminal of winding 2() of transformer T11,

the other terminal of which is grounded.'

One terminal of winding 21 of T10 is connected with themidpoint of winding 22 of 1T11, and the other terminal of 21 is grounded. EOne terminal of 22 is connected with the midpoint of winding 23 vof T2, and the other terminal of 22 with the midpoint of winding 24 of T1. Sections 3 and 3 are connected with sections 4 and 4 by the terminals Ts and T6, respectively. The midpoints of windings 25 and 26 of T8 and T6, respectively, are connected with 27 of T12. In like manner, windings 28 and 29 of Ts and T.1 are connected with windin s 30 of T13. The connec- :tions of the windings 37 and 35 of transfarmers T12 and T1s are similar to those of T10 and T11. The distant end of section 4 is connected across the winding 31 of the reection transformer T1, the other winding '32 of which has one terminal connected with the midpoint of winding 33 of Tg, the other being connected with the. midpoint of winding 31 of T7 and hasuits midpoint connected -wilthwinding 34 of Tg, the latter transformer .being intended to reflect the signal over the circuit 1-4 to the receiver R. In the arran ement shown in'Fig. 8, both pairs in each section together function as an antenna unit for the creation of a voltage from the signaling wave, and each pair also serves as a grounded or metallic circuit to transmit cur rents not only toward the `reflection trans- Jformer but also in the reverse direction to the receiver R.

`Assuming that the desired signalscome in thedirection shownby the arrow, a voltage will` beset up in the section 1-1 in which 'the fnurV conductors of the two pairs are connectedin parallel to ground through the midpoints of thewindings of transformer T11, T11, T1 and T1. This current in the course of its -`.filow over the grounded circuit passes through winding 13 of transformer T1.. It thereby establishes a voltage across winding Awhich causescurrent to flow over a hantom circuit made'up ofthe conductors o` pairs gend andthe windings14, 16, 17 and 19. It willibelseen that `hy'themanner in which the :voltage is` applied tothis phantom circuit, thecurrent flows thereover metallically. The current flows in opposite directions through eiachhialfof each of the windings 14, 16, 17 and19, so that no voltage will be established acrsthe pairs of conductors of the adjacent sections. This current flows through winding miof'transformerTw and creates a voltage across winding 2,V which vwinding has one of itsterminals grounded, and theV other connected tothe midpoint of winding 22. This lvoltige causes current to flow over a grounded phantom Vcircuifrwhich includes windings 21, 22,23, 24, 25, 26, 27 find `35. The flow of currentfthrough all windings except 35 is in such `directions as to roduce no effect upon the other windingso the transformers of which the said'windingsh form a part. The flow of current through the winding 35 establishes @voltage across iwinding 30, which causes currenttoflow overVA a metallic phantom circuit which includes 28, 29, 31, 32 and 33. windings 28, 29, 31and 33 are differential nndelthecondition just stated to windings 25, 26, 32 and 34. The flow of current through winding 32 establishes a voltage across winding 31, which is across the pair of conductors constituting section 4. This voltage will cause current to flow through winding 28 of T3, which in turn will create a voltage across winding 25. This current, which is the reflected signaling current set up by the electromagnetic wave in the antenna-section 1w-1 and augmented by the effect of the electromagnetic wave upon the section 3-3, will continue to travel through sections 3, 2, 1 of one of the pairs and will be impressed by the transformer T1.,t upon the receiver R. The electromagnetic wave will likewise create a voltage to ground across antenna-section 2-2, the four wires of which are connected to ground through the windings 14,16,15 and the resistance 36, at one end of said section, and through windings 17. 19` 18 and 20 at the other end thereof. The flow of current through winding 20 will establish a voltage across winding 22 of transformer T11, which will cause current to flow over conductors of section 3-3 as a metallic phantom circuit. This current willflow through windings 23, 24, 25 and 26 differentially and also through winding 27. The flow through the latter creates a voltage to ground across winding 37, which causes a flow of current over the conductors of section 4 4 as a grounded phantom circuit. This current will be augmented by the current set up therein by electromagnetic wave in space. These currents in section 4 4 will flow through windings 30, 28. 29, 31. 32,33 and 34. Since the flow of currents through windings 30.l 28. 29. 31, 32 and 33 is in a differential manner that is, in opposite directions through halves of each winding there will be no effect upon the other windings of the same transformers with which the said windings are associated. and furthermorethere will be no reflection of current from 32 upon the circuit withwhich 31 is connected. On the other hand, since the current flows through the coils of winding 34 in series. a voltage will be created across winding 33 which will cause current to flow over section 4', which current will create a voltage across winding 26 of section 3 and, in this manner, the signaling current created bv the electromagnetic waves in section 2--2 and 4-4' will be reflected by transformer T. over the pair comprising sections 4 to 1 to the receiver R. These currents will be combined therein in the manner disclosed, for example, in the co-pending application of H. T. Friis,

Serial No. 746.7 53. filed October 30, 1924. A n

ferentially, and then through winding 28 to ground. Winding 28', which serves the same purpose as winding 32 in Fig. 8, impresses across winding the voltage which is created by the eifect of the waves on sections l-l and 3-3, which voltage causes the transfer of the signal over sections 3, 2, 1 to the receiver R. The signaling currents resulting from the effect of the wave on section 2 flow over the conductors of section 3-3, as a metallic phantom, circuit; that is to say, they flow over the conductors of pair 3 in parallel to the midpoint of Winding 25, thence through winding 27 to the midpoint of 26, thence over the conductors of pair 3 in parallel. The flow of this current through winding 27 creates a voltage across winding 37 of transformer TG2. This causes the flow of current over section 4 4 as a grounded phantom, which current is augmented by current created therein by the signal wave. The combined currents of sections 2-2 and 4 4 flow through winding 34 of transformer T8, which creates a voltage across winding 33 which voltage starts the transfer of the signal over the sections 4, 3, etc. to the receiver R.

The directional characteristics of the antenna system, which has just been described from the physical standpoint, are clearly shown in Figs. 10 and 1l by curves having heavy solid lines. These directional curves show the reception ability of the antenna system over a range extending from zero to 180 degrees but it is to be understood that the curve is symmetrical throughout the remainder of the range to 360 degrees. In order to simplify the calculations upon which these curves have been based, the attenuation has been neglected and the velocity of propagation has been assumed to be that light yon both metallic and grounded circuits. To malte the calculations, consider an antenna system such, for example, as that illustrated in Fig. 4 which may be considered as comprising two basic antennae, each made up of a plurality of sections. To obtain the characteristic curve for the antenna system, made up of two basic antennae, the diagram of each half of the system, that is, of each basic antenna, may be calculated from the diagram of a simple wave antenna whose length is that one of the sections of the basic antenna and an array factor corresponding to the directional diagram of an array of vertical antennae located, for example, at the ends of the sections constituting the unit antennae of each basic antenna. The directional characteristic for the complete system may then be obtained from the directional characteristic `of each half and from an array factor corresponding to the staggering and phasing of the two halves. This method of procedure will be clear by considering a specific instance such as that represented by Fig. 10, which shows the characteristic for an antenna system comprising two basic an-` tennae each having two unit antennae, each wave length of the signals. In addition we have a phase lag in the current from A when propagated to B which is =27r So the angle at which the outputs combine is ference will be qb=27r cos where is the The resultant of two equal vectors I1 combining at such an angle is I0=2I1 cos [ig-(1- cos 6);] (2) Since for 0=0, I0=2I1,

cos [00 cos 0)] (3) and this is the equation of the desired array factor.

Upon applying this equation, first to the one-half wave-length staggering between active sections of eachlialf of the system, and then to the one-quarter wave-length staggering between the two halves, we get t-he curves of Fig. l0. The resultant diagram for the whole system is lobtained by multiplying together the directive curve for a single one-quarter wave-length antenna and the two array factors above mentioned. It is almost identical with the diagram of an ideal one wave-length antenna. This might be expected, as the currents froml the individual sections are in this case combined in exactly the same relations as they would be in a continuous wave antenna of the conventional type. Y

An eight-section system would seem to be better than the four-section arrangement, since it would utilize a one-quarter wavelengthY staggering in each half of the system, thus giving a point of zero .reception at 180 degrees; the phasing of the two halves could then be utilized to either reinforce this null point or toproduce others, as desired.

One-half of such a systemA isv shown in Fig. 7. To utilize existing information the directive diagram for each half Vcan be obtained by multiplying together the followwhere y! is the phase shift which may be introduced in combining signals from the two halves of the system in receiver R.

A null point will be produced at an angle 0 when 2 a 6 4mm' i (5) as can be seen bysetting I0=0 in Equation (4; and solving for d. Substituting (5) in ui e Here I refers to the current from each antenna. We desire 13, which is given by: 0

Td: 'l' gg l) cos@- xll-cos 6] This is the equation of the array factor of a staggered antenna system so adjusted as tobe non-receptive to signals arriving from an angle 0.

In Fig. 11, curve (l) shows the result of multiplying together the one-quarter and one-half wave-length staggered array factors. Curve (2) is that of the one-eighth Wave-length unit wave antenna. The resultant directional curve for each half of the antenna system is plotted as curve (3). It is seen to have an ear in the neighborhood of 135 Mrdegrees which can well be suppressed by by the one-eighth wave-length staggering array factor utilizing phasing between the two halves of the system to give a null point at 0=135 degrees. We have calculated such an array factor using formula (9) above, in which we have set The directive curve for the whole system is obtained by multiplying this array factor by the curve for the half system, and is shown as curve (4). It is seen that the halfsystem curve is nearly as good as that of an ideal one wave-length Waveantenna, and the curve for the Whole system is quite good and compares favorably with 4curves for ordinary staggered systems.

Of course, it must be realized that the actual system, in which attenuation has to be taken into account, will not have a null point at 180 degrees. It may therefore be necessary to utilize the one-eighth wave-length staggering to produce a null at 180 degrees. This would leave the ear at 135 degrees to be taken care of by other means (such as broadsiding or further staggering).

It will be apparent that from the foregoing equations, it 1s possible to design a staggered antenna system having a directional characteristic which will give good reception from a desired direction and substantially no reception from the diametrically opposite direction and which willalso have no reception at any predeterminedangle 0 as may be desired to fit in with the conditions existing in specific cases.

While the staggered antenna systems shown in the drawing and described herein comprise only two basic antennae, each of which may be made up of a plurality of sections, it is to be understood that the invention may comprise any number of such basic antennae, all having the same number of sections, which number may vary through a wide range.

It will furthermore be apparent that while the invention has been described as embodied in certain specific forms, it is capable of embodiment in other and different forms without departing'from the spirit and scope of the appended claims.

What is claimed is:

1. An antenna system comprising a plurality of antenna sections, and means to couple the adjacent sections, the said coupling means being arranged and connected with the said sections and to ground in such manner that each section interposed between other sections acts not only as a conducting circuit between the said other sections but also to intercept the electromagnetic Waves in space.

2. An antenna system comprising a plurality of antenna sections each consisting of a pair of horizontal conductors, and means to couple the adjacent sections together, the said coupling means being so arranged and connected with said sections and to ground

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