US1788022A - Directive transmission of energy - Google Patents

Description

Jan, 6, 1931. R. A. HElSlNG DIRECTIVE TRANSMISSION OF ENERGY Original Filed May 16, 1921 7 Original application filed May 16, 1921, Serial No. 470,042. Patent No. 1,562,961, dated November 24, 1925.-

Patented Jan. 6, 1931 UNITED STATES COMPANY, INCORPORATED, OF N EW YORK, N. Y., A CORPORATION OF NEW YORK DIRECTIVE TRANSMISSION OF ENERGY Divided and this application filed September 24, 1925. Serial, No. 58,250.

This invention relates to directive transmission of energy and more particularly to methods ofandsystems fordirectively radiatingand absorbing electric Waves. I

This application is a division of application, $eri'al No. 470,042, filed May 16, 1921, which eventuated into- Patent 1,562,961, granted November 24,1925.

An object of the present invention is to provide a transmission system for radiating energy directively. -,Anothei object of the invention is to provide a focusing antenna which will concentrate the radiated energy The propagation velocity medium is in general the product of its frequency and its wave length in that medium.

In the case of free electric Waves, the propagation velocity is approximately 300,000,000 meters per second. In the case of guided electric waves, the wave length and the wave propagation velocity are functions of the electrical constants of the guiding transmission conductors. giyenby Heaviside, the

wave lengths of a sustained wave. over a circuit having uniformly distributed inductance and capacity is N here is the wave length, a) is the angular velocity or the wave frequency multis plied by 271' and S, R,'L, and C are respectively the shunt conductance, series resistance, series inductance, and shuntcapacity of the circuit per unit length. This wave length evidentlydepends upon the magnitudes of these four electrical characteristics per unit length of the circuit. By'varying these itis possible. to increase or decrease the wave length of the sustained Wave and accordingly, to vary the wave propagation velocity along the circuit.

,Ifla loaded circuit ofthis character is used for radiating or absorbing electric Waves,

the waves, if sustained sine waves, may be propagated along the circuit at a greater velocity than that at which they progress in the ether. If a definite small part of a transmitting antenna be considered, the energy of the wave proceeding from thatpart will be partly propagated along the circuit as a guided wave and partly radiated and propagated out through the surrounding space. Theshape of the; resultant Wave front in the ether will be dependent 'upon the relative velocities of waves propagation in the two media. It is, therefore, possibleto give a radiated ave variously directed fronts depending upon the loading of the antenna cir cuit. It is likewise possible to so absorb the directed radiant wave at a receiving antenna as to cause all of the absorbed energy to p cumulatively affect the receiving device; of a wave in any" According to the present invention a radio transmitting or receiving antenna is made long with respect to the Wave-lengthof the wave. to betransmitted or received. In order to. make this antenna behave as a conductor of infinite length and thereby avoid the production of a reflected wave, it is desirable to terminate it inan impedance element-having an impedance equivalent in magnitude and character to the iterative or surge impedance of the antennaitself at the terminating point.

At intervals corresponding to a fraction of a wave-length, the antenna is loaded by inserting seriescap'acity or shunt inductance, or botluto make its wave propagation velocity for the waves tobe transferred higher than the corresponding wave propagation velocity in ether. Since the energy in a radiating antenna decreases with increasing distance from the source, it is desirable in order to secure the best results to progressively increase the radiating factor of the antenna and t -is is done by increasing its height.

For focusing on a single fixed receiving point, a combination of two antennae arrangements, employing the type of antenna above described, may be used. I A parallel arrangement of two such antennae permits radiation in only one lateral direction instead of intwo lateral directions as would otherwise PATENT OFFICE RAYMOND A. HEISING, or MILLIBURN, NEW JERSEY, ASSIGNOR TO WESTERN nnnc'rnro maintaining them parallel the while, in the arc ofa circle. Of course, either one of these expedients can be used alone, with a corre-' spending reduction from the optimum degree of focusingrealizablewhen both of them'are used.

Qther objects of the invention will be ap parent upon consideration of the following detaileddescription taken in connectionwitli v the accompanying drawing in which:

' Fig. 1 illustrates diagrammatically an an-M tenna which is long relative to the wave length" of the emitted wave and which is loaded with both series'capacity and shunt inductance to increase the velocity or propagation above that or ether waves;

Fig. Zillustrates a modification of the antenna of Fig.1 to the extent that only series capacity'is relied upon to produce the same ultimate result and in whicln i'urther,the an' tenna is progressively increased in height to provide uniform unit" radiation, the crosssection being correspondingly progressively increasedin size to maintain. the unit shunt capacity (the natural capacityte ground) constant; e j I Fig. 3 illustrates a unit section of the an tenna of Fig. 2 y

:Figfet illustrates a circuitwhich is a combination of that of 1 and Q'eXcept that it utilizes shunt inductance alone, instead of series capacity alone or the combination of the two, to obtainthe same ultimate result; Fig. 5 is a diagram indicating the directive operation of loaded antennae of the inven m. a w I Fig.6 a diagram of current and energy distribution in antennae of the type disclosed;

Fig. 7 is a radiation coefiicient diagram. for antennae of thistype; V

Fig. 8 illustrates an antenna systeni arranged for neutralizing the directive energy in one of the two lateral directions in which energy would otherwise be radiated; and

Fig. 9 illustrates asystem, otherwise the thereto for radiation. Antenna 2 is preferably of a length several times the wave-length defined in equation (1). This wave-length depends upontheinductance and capacity. per un t length of the radiating circuit. In

telephone lines loaded with inductances as is the common practice, the wavelength is greatly shortened. In fact, in loaded line cuit.

telephone practice, the wave-length multiplied by thefrequency may give a velocity of the order of 90,000,000 meters per second instead of 300,000,000 meters per second which is the velocity of light and of tree electric waves. Since increasing the inductance per unit length, which is done in loading televihone lines shortens the wave-len th at a l 7 2:

given-frequency, it willbe evidentthat it is possible by reducing the inductance per unit length, to increase t hewave-length of a unit circuit. H" the resistance and shunt conductance of the circuit .are made zero, Equation (1) reduces to .From, Equation (2) it would appear that, with circuits of negligible series resistance and shunt conductance .per unit length, either reducing the series inductance per unit length or the shunt capacity per unit length,

should increase the'Wave-length and, therefore, increase the velocity ,at which a given frequency wave is propagated along the cir- This can actually be accomplished in several ways, it being remembered that the long antenna with its'oapacity to ground and the return ground conducting path may, if uniform and if properly terminated, be treatedas any other. alternating current conducting circuit.

, One simple way to increase the velocity or the wave propagation is illustrated in Fig. lin whichseries loading capacities 3 and shunt inductances 6 are inserted inthe conducting'line and are spaced much in the same'inanner. as are the loading inductances in loaded telephone lines. These loading inductances and capacities should be separated by distances small compared to the wavelength, so that the effect of uniform distributionjofthe capacity is approximated. AL

though theenact number of such elements may vary greatly, it is desirable to use eight or more per unit length. For simplicity onlya few elements are shown. The action of this capacity loading is to introduce series reactance opposite in sign to that of the natural series inductance, and accordingly to produce lower efl'ective series inductance per unit length. The action of the induc tance loading is to introduce shunt reactance opposite in sign to that of the natural shunt capacity reactan'ce and hence to produce higher efl'ective shunt capacity reactance per unit length. It will, of course, be" understood that either series capacity loading or shuntinductance loading alone may be used.

As has been previously mentioned, a circuit ot this character of finite length must be properly'terminated to avoid having a wave reflected from the free terminal. Areflect ed wave produces nodes along the circuit and introduces complications of various sorts. If the transmitted wave gives directive radiation in the general direction of its transmission the reflected wave will give directive radiation in the opposite direction. To eliminate the reflected wave and prevent this reverse transmission, it is only necessary to terminate the line with a proper impedof increasing size is employed. Anelement I of the recurrent network thus formed is illustrated in Fig. 3, in which the natural series inductance 4t and shunt capacity 5 of the conductor, both indicated by dotted lines, constitute together with the loading capacity 3 a uniform section of theline.

Fig. 4 illustrates another method of. an-

tenna loading which consists in reducing the effective shunt capacity of the circuit. This is accomplished by connecting between the line and ground, loading inductances. 6 which are preferably spaced eight or more to the wave-length; although in thiscase, as well as in the case of the series capacity loading, a considerable variation in this number may be permitted. f

It is a well known fact that the effective capacity of a condenser is reduced'by connecting in parallel with it a large inductance, while the effective reactance of the condenser is increased. At a given frequency the nat-' ural capacity 5 of a unit section of the conductor with the inductance 6 shunted around it has several times the capacitative react ance that the capacity 5 alone has.

Resistance tends to shorten the wavelength. It is accordingly desirable to make the resistance of the antenna conductor very low. In loading systems of the kind described, the variation in effective capacity or. effective inductance will be particularly marked for a given frequency, and wave velocities for such frequencies may be attained exceeding that of light. It is apparent that the arrangements of Figs. Qand 3 each embody the use of an individual one of the two loading means that are embodied in the system of Fig. 1 By proper design of the impedance elements substantially equally good results can be obtained for all three methods of loading.

The fact that a wave may be made to travel over a. circuit with a velocity greater than thatof free electric waves or light, maybe made use of in directive transmission. Re-

' ferring to Fig. 5 in which OA may represent the same phase. I a reenforcing of the wave ln'th-e direction a plan or top view of a long loaded antenna of the type, for example, illustrated in Figs. 2 and 3, suppose that the source of waves is located at terminal S. An electrical disturbance occurring as an alternation of electrical potential at this point travels along the circuit to a point A. By radiation, point becomes the center of a disturbance of like form which emanates in alldirections through space. t I

If the space velocity i. e., the velocity of free electric waves, is such that the radiated wave travels a distance OB during the time that the'guided wave travels the distance OA, the wave front of the radiated wave in the space surrounding the antenna will take the: directions BA and CA. Thedirection of propagation of the radiated wave being perpendicular to this front is indicated by the arrow. The angle between this wave front and the antenna e 'idently depends upon the ratio of the guided wave velocity to the fre wave velocity.

If right angle triangles are drawn similarly to Fig. for the case where the base 0A equalsthe radii OB and ()0, the hypothenuses AB and AC will be infinitesimally short and at right angles to the base GA. This illustrates the critical case in which the ratio'ofvelocities is unity. lVhen this ratio is unity, the wave will accordingly be propagated in the direction of transmission along the circuit, i. e., 021.

The physical basis for the phenomenon when the ratio is unity is made readily apparent by noting that as the wave is radiated in the direction of antenna 0A, since the wave is propagated along the antenna at the same velocity, new centers of oscillation are continuously being established on the wave front which in turn give rise to waves which travel in the direction 0A coincident with those from the original wave source 0 and have There accordingly results Ofin The original wave and the waves radiated from these centers of oscillation in the opposite direction are opposed in phase and mutually extinguish each other.

lVhen the ratio is infinite the wave front will obviously be parallel to the conductor and the direction of propagation will be perpendicular to the-antenna. When the ratio is less than unity, the antenna isnot directive. "In Fig. 4, the terminating element Z is shown as comprising series resistance and capacity. That the terminating impedance may be closely approximated by resistance alone will be evident from a consideration of the specification of'United States patent to Heising 1,313,483, patented August 19,1919. In order to secure the best results, the c i rected wave should be of uniform intensity throughout its wave front. This requires that the radiation in power should be the same for each unit length along the line. In

line having uniformresistance, inductance,

and capacity, the current decreases logarithmicall and the radiation will accord-in d.

to the terminal A, where the remainder of, the energy should be absorbed by the termn nating impedance Z. To secure energy distribution of this character, as illustrated by line 7 of Fig. 6, the current along the circuit must vary as the square root of theenergy as represented by curve 8 of Fig. 6.

That the radiated power may be uniform along the line with decreasing current, it will be eviden that the ration constant of the antenna or its radiation resistance must be gradually increased along the line. It should vary according to the reciprocal of the square of the current amplitude, as indi cated by curve 9 of Fig. 7 which represents the radiation coeiiicient or radiation resistance.

Since the radiation resistance varies approximately as the square of the height of the line, this variation in resistance may be secured by varying the height of the line so as to make this height approximately proportional to the square root of the required radiation resistance. This is indicated in Figs. 2 and 4: in which the height of the line increases from the source to the remote terminal in accordance with the requirement stated. The gradually increasing height with decreasing current will produce unipoint that the height of the antenna will not,

because of the very small current, berequired to exceed practical limits in order to maintain constant radiation.

l Vith an antenna of varying height and a constant size conductor, the inductance and capacity per unit length will change. It is possible to progressively vary the magnitudes of the loading reactances along. the line so as to maintain the wave velocity constant.

As an alternative method the diameter of the conductor itself may vary progressively with the height. With this latter arrangement the loading inductances and capacities may remain the same per unit wave length if a constant wave velocity is to'be maintained throughout the length of the conductor. Figs. 2 and l indicate a variation in the diameter of the conductor to maintain the capacity per unit length substantially constant.

As indicated by Fig. 5 there is directive radiation in two lateral directions. The radiation diagram would accordingly be a double lobed figure. The. direction of extension.

of the lobes and the angle between themwould be function of the velocity ratio. 7 In general,increasingthelengthof the antennawill, increase. the directivity as. measured'by the dths of the two lobes." It also increases the directivity to the extent of decreasing the prominence of'm'inorlobes whose presence is incidental to the productions of the major lobes and which, of course, detract from the directivity. Fig. 8 of HeisingPatent 1,562,961, granted November2el, 1925, above referred to, illustrates a radiation diagram for one set of conditions.

'Anarrangement of multiple antennae for si essing ra diationin one ofthe directions 001 esponding: to'these lobes is illustrated in Fig.8 in which parallel directive antennae 20 and 21 .so'spaced thatftheir respective energy transmission lobes 22' and 23 from the tern iin als 2% and 25, connected with the source, extend in the same direction, and neutralize iii-space. If energy of the same phase is simultaneously supplied at points 2& and 25, and if these points are a half wavelength apart in one direction in which the respective antennae radiate most powerfully,

the effectof the energy radiated from point 25 will be to oppose and neutralize that radiated from point 24 in this direction. 7 This is for the reason thatfor all points in space in this direction these radiated energies will be opposite in'phase. In other words, lobe 22 will neutralize lobee23. If the distance between the points 24 and 25 does'not correspond to a half wave-length, the phase of the energyisupplied to one of the antennm may be so shifted by a variable impedance device 80 that the points 24 and 25 will tend to radiate energies; which will nevertheless neutral ize in space in the direction of the lobes 22 and 23. This will leave only the lobes 26 which are similarly directed and which are vectorially additive.

The above described-antenna arrangement accomplishes focussing, in part, since its use results in the confinement of the radiation to a single principal direction However, the radiation in that direction is dispersive in character. That is, the single resultant lobe of the radiation diagram, in general has the shape of each of the lobes of Fig. 8. Although maximum radiation is in a definite direction, namely along the center line of the lobe, the direction differentiation is much less than itwould be if the outward extremity approximated a point rather than a smooth Further focussing may accordingly be accomplishedby an arrangement of antenna which will give this pointed characteristic, as a result of which the antenna may be said to focus on a distant point instead of radiat ing in a given direction.

feet on each of the two lobes of the radiation j Fig. 9 illustratesan arrangement foreccomplishing this purpose. ltconsists or" two antennae arranged asin Fig. 8 but laterally curvedin the arc of a circle so as to tend to focus at a point at the common center of I curvature for thetwoantennae. The figure is les liagraminatic than Fig.8, as illus tratn one type of SPGClfiC antenna that 1s adapted tobe used in thearrangement, name sclos'edin Ol' viously,'e1ther ly that a. q of the other tyne iiustral d oyl lgs, 2 and 3, eithcrwith orwithout thezprogressive .ele- 'vation, mi ht equally Well he used and the types need not necessarily be the same for the two antennae oi the pair. Th s figure also'difi'ers from Fig. 8 in illustratmganmductive, instead of a conductive, coupling of I the antennae to the source, and in the dias figure also illustrates a means, al-

ternative to the curvediantennaarrangement, for accomplishingthe same type of focusing, andwhos'e'eilect may, with ultimate benefit, be superposed on it, in an arrangement like that illustrated in whichboth means are simultaneously operative." It consists 1n the useofnon-uniform loading and specifically of the use of load ng des gned to progresslve' 1y increase the propagat on velocity as the or having non-uniform loading, may be used 7 to produce focusing as measured by the efdiagrani. Similarly, the use of two'antennae, as in Fig. 8, maybe used to focus to the extent that focusing may be accomplished by acting to modifiy theradiation diagram as a whole to reduce it to one lobe. Each of these means achieves a definite step in the method which can be accomplished completely by the arrangement of Fig.9, and they are individually capable of being used either alone or in other combinations.with'like eilect or in the preferred combination illustrated.

Throughout the specification the various features of the invention have been explained from the standpoint ofradiation" at a transmission station. The principles of wave'abjsorptlon are in general the same as those of wave radiation. It is therefore, to be understood that the various features of the invention are equally applicable to receiving systems and the various circuit diagrams may each be considered as representations of a rece-lvlng system with the simple substitution of receiving apparatus for the carrier wave source. 7 l

ramniatic illustration ofthe phase changer.

stantially on a' point.

Intheappended claims the transfer of energy. either by" radiation from. an antenna toitheether or byabsorption ,from the ether to the antenna is analogous. to the transfer of energy between media: of difierent char.-

acteristi csf In telephone parlance the term 7 transducing. is commonlyiused .to describe generallyfatransfer of energy without limitat'ionl as to "the nature -0f the transfer.

lVhe'rever this term occurs .in the appended claims, it will;be understoodithat it is intended tobe generic both to, radiation and absorption; of wave'energy as well as to the transfer generally of energy from a medium 'ent characteristics.

What is claim'edis causing saidv antenna to radiate directively 1n lateral 'ClllQCt-IOIIS, and means-for neutralizingthe; radiation in one of said directions,

said antenna being curved so as'to concentrate saldlradlat on 1n the earths plane sub- 2L A, directive radio wavesjof .a -given frequency'at a velocity exceed ng.. that of light, and a similar, an tenna so" positioned with respect to the first that the, corresponding points of thetwo antennae are equidistant and thatv the radia-.

' .tion from a, terminal of one antenna is directed a long thesame axis as the radiation from a 'correspondlng termlnal of the. other antenna, said antennae belng, curvedso that thekresulta'nt radiation in the-earths plane is substantiallyconcentrated one point. i 3. Aradi os-ystem comprising two horizon tal similarly loaded, bilaterally directive, an tennae, laterally separated,.both included substantiallyf in the earths plane, each gcurved; substantially the arc of a circle in said plane, and corresponding points of the two.

being equidistant, a signaling device,:.andn-O means fortransferring energy between said antennae and said device.

4. A radio system comprising two horizoni tal, similarly loaded. bilaterally directive; an-

tennae. both included in a plane substantially cO-incidentWith the vearths plane, laterally separated, and having corresponding. points of the two equidistant; and each. said antenna- I being curved in thegarc of a circle=in said plane, anda single source for supplying periodic energy to said antennae.

5. A radio .system.'comprising two horizon tal, similarly loaded, curvilinear, bilateral directive, .coplaner, antennae,laterally "sepa rated a h i g corresponding points ofthe two equidistant,",said plane being; sub.-

stantiallycoincident with the. earths plane, and means forsupplyingenergy of'the same I periodicity to said antennae.

' 6. A radio system compri whpael e g im l r r ead a bil er y- 1e of ertain char'acteristicsit'o media 0f difi'eri systemicomprising an antenna :loaded, .so. asv to transmit energy.

sing two horizons 1 Us;

1; In combination,anfantenna, means for rective, antennae, each'lying in theatre of a circ'leand the two occupying a common-plane substantially co incident with the 'earths plane, andmeans forsupplying energy of dilferenceto said antennae.

I "7;;A directive radio system comprising 7 two similar antennae each'of which is-adapted to'dire ctively radiate energy of a given frequency, said antennae beingso positioned that they neutralize each other for transmission in a given direction, and so curved that the resultant radiation in the earths plane is substantially concentrated on a point.

8'. In combination, a lo'laterallydirective antenna, means for supplying" energy thereto and a similar antenna with similar bilaterally "directive characteristics positioned to.

Y neutralize radiation from said first antenna inone direction. I v I V v '9. In combination, a bilaterally directive antenna a second bilaterally directive an- 7 along the same axis asthe radiation from a;

corresponding terminal of the other antenna.

4 "1 1. A directiveradio system comprising tenna, a source of energyconnected to both said antennae to supplygen'ergy' thereto, said antennae being so positioned with respect to each other as to neutralize radiation from' one of said antennae in. one direction for which it would otherwise be normally' directive. t a Y 10. A directive radio system' comprising a'wave antenna loaded so as to transmit energywaves of a given frequency at a velocity exceeding that of light, and a similar an tenna so'positioned with respect to the first that the corresponding points ofthe two antennae are equidistant and'that the radiationfrom. a terminal. of one antenna is'directed two similarly loaded horizontal antennae laterally separated and-having corresponding points of the 'tWo equidistant, a signaling device, and means for transferring energy bei I ure tween said antennae and said device. I

12. directive radio system comprising two similarly loaded horizontal antennaelaterally separated and having corresponding points of the two equidistanhand a vsingle source for supplying'periodic energy to said antennae. r v

13. A, directive radio system comprising two similarly loaded horizontal antennae lat:

the same periodicity land of, a desired phase.

two similar horizontal antennae each of which directively radiates'energy of a given frequency, said antennae being so positioned that they neutralize each other for'transmission in a given direction.

16; A horizontal conductor curved laterally in the arc of a circle throughout its length,

and means for loading said conductor so as to cause it to radiate energy directively throughout its length.

17. A focusing transmitting antenna comprising a loaded circuit curved in the arc of a circleand having as its center a point on 1 which 1t 1s desired to. focus the radlated energy'which is incident on the earths plane, and having its constants so adjusted that Waves of a given frequency are propagated along said vcircuit at a velocity exceeding that of light.

antennafor preventing reflection of said waves back toward said source.

In;witnesswhereof, I hereunto subscribe my name this 18th day of September, A., 1)., 1925. r

V a RAYMOND A. HEISI NG.

erallyseparated and having corresponding.

points ofthe twoeg-uidistant, and means for V said-antennae.

f A. directiveiadiosystem comprising i two similarlyloaded horizontal, antennae lat-.

erally' separated and having. corresponding lying energy of'the same periodicity to points otthe tWo equidistantfand.means for 1 T;

supplying: energy of the same periodicity V I j and of a desired, phasedilferenceto said antennae'w I 15. A directive radio system comprising f.

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