US2458885A - Directive antenna system - Google Patents

Directive antenna system Download PDF

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Publication number
US2458885A
US2458885A US568248A US56824844A US2458885A US 2458885 A US2458885 A US 2458885A US 568248 A US568248 A US 568248A US 56824844 A US56824844 A US 56824844A US 2458885 A US2458885 A US 2458885A
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Prior art keywords
lobe
lobes
minor
maximum
plane
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US568248A
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English (en)
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Clifford A Warren
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AT&T Corp
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Bell Telephone Laboratories Inc
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Priority to GB28972/46A priority patent/GB624876A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/29—Combinations of different interacting antenna units for giving a desired directional characteristic
    • H01Q21/293—Combinations of different interacting antenna units for giving a desired directional characteristic one unit or more being an array of identical aerial elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/2664—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture electrically moving the phase centre of a radiating element in the focal plane of a focussing device

Definitions

  • the dual reflector system comprises two parallel horizontal arrays of colinear dipoles and a separate large cylindrical parabolic reflector associated with each array, and it is especially suitable for use in a dual plane lobe switching radar antenna system. Accordingly, it appears desirable to reduce the minor lobes, in the directive pattern of a dual reflector system, in a more satisfactory manner than heretofore effected.
  • an auxiliary antenna system is positioned adjacent to the dual reflector or main antenna system disclosed in the eopending Higgins-Warren application and is utilized for securing the desired minor lobe reduction.
  • the single primary lobe of the main .minor lobes are utilized for securing the desired minor lobe reduction.
  • auxiliary antenna pattern and the single primary lobe of the resultant or combined pattern are termed herein the major" lobe, the maximum" lobe and the principal lobe, respectively; and the secondary lobes of the main, auxiliary and resultant patterns are termed herein the "minor,” the minimum” and the “subsidiary” lobes, respectively.
  • the auxiliary antenna system comprises a single cylindrical parabolic reflector and a: pair of colinear dipoles aligned with the horizontal focal line of the small reflector.
  • the auxiliary antenna system and the main antenna system are connected to the same radar transceiver.
  • the vertical aperture dimension of the auxiliary reflector and the horizontal dimension of the auxiliary antenna system are relatively small compared to the corresponding dimensions of the main antenna system and are such that, in each switching plane, the width of the maximum lobe pattern of the auxiliary antenna system is at least as great as the total width of the major lobe, the nulls adjacent thereto and the first Amplitude control means are provided for regulating the currents supplied to or received from the two antenna systems, whereby the intensities of the maximum lobe of the auxiliary antenna and the aforementioned minor lobes may be equalized substantially.
  • the two first minor lobes of the main antenna system are cophasal, and the major and first minor lobes of the main antenna system During the dual plane lobe switching operation, the phase of the major lobe remains constant.
  • a phasecontrol means is inserted in the line to the auxiliary antenna system for securing an auxiliary antenna maximum lobe having a phase similar to that of the major lobe and opposite that of the first minor lobes.
  • Fig. 1 is a perspective front view of one embodiment of the invention
  • Figs. 2and 3 are, respectively, a front diagrammatic view and a side diagrammatic view of the embodimentof Fig. 1;
  • Figs. 4 and 5 are theoretical one-way directive patterns used for explaining the invention.
  • Figs. 6, '7, 8 and 9 are measured one-way dior secondary antenna member 2 and a lower cylindrical parabolic reflector or secondary antenna member 3, each having a horizontal axis 4. a horizontal focal line I, a common vertical latus rectum 6, an opening or aperture 1, and a focal distance d of a quarter wavelength.
  • the apertures are relatively large and of equal size and, in the case of each reflector, the longitudinal dimension m is approximately equal to twice the transverse dimension n, so that the entire aperture of the main antenna comprising the two reflectors 2, 3 is substantially square.
  • the axes 4, Fig. 3 are parallel to the on-axis or zero degree transceiving direction 8 which coincides with the equi-intensity direction for the dual plane lobe switching system or, stated differently, coincides with the axis of the scanning cone.
  • Reference numeral 8 denotes an auxiliary antenna system comprising a cylindrical reflector l cally related to the dimensions of reflectors 2 and 3.
  • the side dimension a of the square opening i3 is two wavelengths and the side dimension m, or 2n, of the square opening for the two reflectors 2 and 3' is about six wavelengths.
  • the dimension a is in the. order of one-third of dimension 111..
  • the main antenna system I and the auxiliary antenna system 9 are supported by a yoke assembly comprising a rotatable vertical shaft and bearing l4, a horizontal turntable member i6 attached to shaft I4 and a pair of uprights or vertical arms IS.
  • the two reflectors 2, 3 are secured to a framework comprising two side members l1 (only one shown in Fig. 1) which are mounted on a rotatable horizontal shaft l8.
  • Shaft I8 is supported on bearings IS in arms I6.
  • means (not shown) are provided for rotating the entire antenna system' in the horizontal or azimuthal plane and for tilting it in the vertical or elevational plane.
  • the auxiliary antenna system is supported by struts 2
  • reference numerals 22 and 23 denote the primary antennas associated with the upper and lower reflectors 2, 3, respectively,
  • Each primary antenna comprises eight dipoles 24 arranged in a linear array and aligned with the reflector focal line and each array 22, 23 comprises two subarrays of four colinear dipoles.
  • the left upper, right upper, left lower and right 23 denotes a translation device, such as a radar transceiver, which is connected by the coaxial principal line 24 and the coaxial main line to the junction 3
  • Each of the above-mentioned coaxial lines comprises an inner conductor 33 and an outer conductor 38.
  • the sixteen dipole lines 23 have equal lengths, the eight branch lines "have equal lengths.
  • the four subarray lines 21 have equal lengths and the two array lines 32 have equal lengths, so that the paths connecting device 28 to the. sixteen dipoles have equal electrical lengths.
  • Numeral 3'! denotes an adjustable amplitude control means, such as an adjustable attenuator, included in the main line 30.
  • Reference numerals 33 denote four short-circuited quarter-wave coaxial lines each of which is bridged across a different subarray line 21 at a point a short distance from the junction 33 or 34, as explained inthe copending Higgins-Warren application.
  • Numeral 33 denotes a lobe switcher having a base member 40, four stator plates 4
  • the four dipoles 24 in each of the four subarrays are connected by four individual coaxial dipole lines 25 and two coaxial .branch lines 28 to a coaxial subarray line 21.
  • Numeral and a rotor 42 designed for capacitive association with two stator plates.
  • is connected to the inner conductor 33 of a coaxial phasing line 43 through a different switch 44, and the outer conductors 38 of phasing lines 43 are connected to base member 40.
  • the other ends of the four phasing lines 43 are each connected to the approximate midpoint of a different quarter-wave coaxial line 38 so that, as explained below, in the case of each of lines 38, the rotor 42 applies the correct capacity to the midpoint of the line.
  • the phasing lines 43 have negligible lengths, or lengths each equal to an odd multiple of a half wavelength.
  • the phasing lines 43 are omitted and the capacity is successively applied directly by the rotor 42 to the midpoints of the four quarterwave lines 38 which project into the lobe switcher 39.
  • Numerals 45 and 46 denote a motor and shaft for driving the rotor 42.
  • the main antenna system just described is basically the same as that disclosed in the Higgins-Warren application, the primary difference between the two systems being that the phasing lines 43 in the system of the aforementioned application are each connected to the subarray line v2'I through a halfwave line instead of a portion of a short-circuited quarter-wave line 38.
  • Reference numeral 4! denotes the primary antenna associated with the reflector ill of the auxiliary antenna systemv 3.
  • the primary antenna 41 comprises two spaced dipoles 24 alignedwith the focal line H of the auxiliary reflector Ill.
  • the two dipoles 24 are connected by the dipole lines 23, the coaxial auxiliary line 48 and the principal line 29 to the translation device 28.
  • the auxiliary line 48 includes an adjustable attenuator 31 and an adjustable phase shifter 48.
  • adiustable impedance transformers are inserted at the line junctions'and at the dipole junctions, for the purpose of matching the impedances throughout the system.
  • a conventional short-clrcuited quarter-wave stub (not shown) is provided at the center of each dipole for rigidly connecting the inner coaxial line conductor 35 to the outer coaxial line conductor 38 through a auaaea' high impedance.
  • the amplitude of the current delivered to themain antenna I may be controlled by the impedance transformer at thejunction 66 of the principal line 26 and the main line 36, and the amplitude of the current supplied to the auxiliary antenna 8 maybe controlled by the impedance transformer at the junction 60 of the principal line 26 and the auxiliary line 48.
  • pulsed energy is conveyed through the adjustable attenuator 81, and over lines 29, 36, 82, 21, 26 and 26, between the device 26 and the sixteen dipoles 26 of the main antenna system i.
  • pulses are conveyed through the adjustable attenuator 31 and adjustable phase shifter 69, and over lines 26, 68 and 26, between device 28 and the two dipoles 24 of the auxiliary antenna system 9.
  • the high frequency pulses emitted by the combined antenna system i, 6 are, after reflection at a target, returned thereto as echo pulses. Since only the transmitting operation of the antenna systems i, 9 is described in detail herein, it should be pointed out here that the transmitting and receiving directive patterns are, by virtue of the reciprocity theorem, substantially the same.
  • the lobe switcher 39 is disconnected from the four quarter-wave lines 38 and the energies delivered to the sixteen dipoles 24 are cophasal.
  • the quarter-wave linestfi remain bridged across lines 21 but they do not affect the phases of the currents in the subarray lines 21, since they have a high impedance.
  • a capacitive impedance is bridged across any of the four quarter-wave lines 66, the electrical length, and impedance, of the quarter-wave line is changed to a value which affects the phase of the current in the associated subarray line 21.
  • Each capacitive impedance retards the phase of the current, say about sixty degrees, in the subarray line 27 to which it is momentarily connected.
  • the lobe switcher functions to change the phase of one-half of the sixteen dipoles relative to the other half, the phases of the upper half, right half, lower half and lefthalf being changed in succession.
  • the beam or direction of maximum action for the antenna system i is positioned off-axis, that is, at an angle to the on-axis direction 8, and as rotor 62 rotates, lobe switching between the up" and down beam positions and between the "left? and "right” beam positions is obtained, as explained in the Higgins-Warren application.
  • the cone angle is dependent upon the value of the capacitive impedance mentioned above and in one system is about three degrees.
  • the direction of maximum action for the system may be aligned with the on-axis direction 8 by opening the four switches 44.
  • curve 6! illustrates a theoretical on-axis directive pattern for the main antenna system i taken alone.
  • includes a major lobe 62, first nulls 66, first minor lobes 54, second nulls 66, second minor lobes 66, third minor lobes 51 and fourth minor lobes 66.
  • curve 58 illustrates a theoretical oil-axis directive pattern for the main antenna system I taken alone when the switches 44 are closed.
  • the off-axis pattern 58 includes a major lobe 66, first nulls 6i, first minor lobes 82, second nulls 63, second minor lobes 64, third minor lobes 66 and fourth minor lobes 66.
  • Each of curves 6i and 68 represents either the electric or magnetic plane pattern, the electric or E-plane being horizontal and the magnetic or H-plane being vertical inasmuch as the dipoles 26 are horizontal.
  • the first minor lobes are cophasal and have a phase opposite to that of the major lobe, as shown on the drawings by the plus and minus signs.
  • the phase of the major lobe 62 of the on-axis pattern Si is zero
  • the phase of the major lobe 66 of the oilaxis pattern 69 is not zero but is --30 degrees, inasmuch as the lobe switcher introduces a lag of 60 degrees in one half the dipoles and does not affect the phase in the other half of the dipoles.
  • the lobing or beam direction would be the same in both cases since, in so far as directivity is concerned, it is immaterial whether the 60 degree out-of-phase relation is secured by retarding the phase of onehalf the system and leaving the phase of the other half the same, or by retarding the phase of onehalf the system 30 degrees and advancing the phase of the other half of the system 30 degrees.- In practice, it is more practical to use a simple lobe switcher, such as the switcher 39 which, as already stated, changes the phase of only onehalf the dipoles.
  • first minor lobes 66, Fig. 4. are symmetrical on each side of the major lobe 62 and that these minor lobes are of substantially the same amplitude.
  • Fig. 5 when the major lobe B0 is shifted to one side of the on-axis direction 8 the intensity of the first minor lobe 62 on the opposite side of the on-axis direction 6 is increased considerably,
  • first minor lobe 62 assumes a position closer to the .on-axis direction 6.
  • intensity of the first minor lobe 62 on the same side of axis 8 as the shifted major lobe is decreased, and this first minor lobe assumes a position farther away from axis 8.
  • the first minor lobes 56 and 62 of patterns 6i and 59 for the main antenna system I that is, for a prior art system such as that disclosed in the Higgins- Warren application, are highly detrimental and may, in radar operation, cause false crossovers and ambiguous indications. As will now be explained in connection with Figs. 4 and 5, the
  • auxiliary antenna system 9 utilized in accordance with the invention, functions to eliminate or at least reduce substantially the first minor lobes 56 and 62 which are otherwise present when switches 44 are either open or closed.
  • reference numeral 61 decases notes ideal or theoretical maximum lobe pattern, talien in either the E-plane or the H-plane, of the auxiliary antenna system 8.
  • the maximum lobe has an angular width, taken at the 50 per cent or half-power point. which is primarily a function of the size of the auxiliary refiector opening it, and an amplitude or height dependent upon the adjustment of the attenuator 48.
  • a maximum lobe may be obtained having a width and a height, that is, a shape, such as shown in Fig. 4.
  • the maximum lobe 61 overlaps the major lobe 82 and the first minor lobes 84 and has. at its base, an angular width greater than. that portion of the main antenna pattern 8
  • the phase of the maximum lobe 81 is adjusted, by means 01' phase shifter 48, so that the major lobe 52 and the maximum lobe 61 are cophasal, and the cophasal first minor lobes 84 and the maximum lobe 81 are opposite in phase or antiphasal. Since the major lobe 52 has a constant zero phase when in the onaxis position shown in Fig. 4, the phase of the maximum lobe 81 for this condition is also zero.
  • the two fields from themain system I and the auxiliary system 8 add together in space to produce the resultant or combined pattern 88 havin'g'a principal lobe 88, first nulls 10, first subsidiary lobes 1!, second subsidiary lobes 12, and third subsidiary lobes 18. More specifically,
  • the amplitude or field intensity Em of the major lobe 52 and the amplitude Ea of the maximum lobe 61 combine to produce a maximum resultant intensity Em+Ee, since in direction 8 the two lobes 52, 81 are cophasal'.
  • the unequal maximum amplitudes of the major lobe 82 and principal lobe 68 are, for the sake of simplicity, shown equal.
  • onehalf of the two patterns for example, the pattern portions included in the angular sector at the left of axis 8, as the direction orangle increases from zero the amplitude of the major lobe 52 decreases, in accordance with the slope or shape of the lobe, to zero at the first null 53.
  • the amplitude of the maximum lobe 81 is fairly constant and, since lobes 52 and 61 are cophasal, the portions of lobes 52 and 61 included in this small sector add to form one-half of the central portion of the principal lobe 89 of the resultant pattern 88.
  • the intensity of the principal lobe 88 is equal to the intensity of maximum lobe 61.
  • the amplitude of the main antenna pattern i increases, in accordance with the shape of this minor lobe. Since the first minor lobe 54 and the maximum lobe 81 are antiphasal, as previously explained, the amplitude of the resultant pattern 88 in this angular section will be equal to the diflerence between the amplitudes of the maximum lobe 81 and the first minor lobe 54.
  • the amplitude of the resultant pattern 88 iszero and the first null 18 of the reand null II, the maximum lobe 81 and the first minor lobe 84 oppose each other and the small diil'erence between their intensities forms a portion of the first subsidiary lobe 1i of the resultant pattern 88. It will be noted that the maximum lobe 81 slightly'overlaps the second minor lobe I8.
  • the overlapping should be kept to a minimum, by proper adjustment of the shape of the maximum lobe 81, inasmuch as the maximum lobe 81 and the second minor lobes' B8 are cophasal. Since both halves of pattern 8! and both halves of maximum lobe 81 are symmetrical about, axis 8, the pattern portions at the right of axis 8 combine to produce the right half portion of pattern 88, in the manner explained above.
  • reference numeral 18 designates the maximum lobe, taken ineither the E-plane or the H-plane, of auxiliary antenna pattern.
  • the lobe 16 is the same, except as to phase, as the'lobe 81, Fig. 4.
  • the main antenna is lobe than that portion of the main antenna pattern 69, which includes the two first minor lobes 62, the first nulls 8i and the major lobe 80.
  • the phase of the major lobe is 30 degrees and phase shifter 49, Fig.
  • the shifter 49 is adjusted so'that the maximum lobe 18 has a -30 degree phase, whereby themajor lobe 60 and the maximum lobe 18 are cophasal, and the maximum lobe 18 and the cophasal first minor lobes 82 are anti-phasal.
  • the shifter may be replaced by a section of coaxial line having the proper length to effect the desired phase shift, that is, to secure cophasal maximum and major lobes.
  • the two fields from the main system I and the auxiliary system 9 add together in space to produce the resultant pattern 11 having a principal lobe 18, a broad or flat null 18 on the left or shift" side of axis 8, a sharp null 88 and a first subsidiary lobe or pip 8
  • the particular first i minor lobe 62 the amplitude oi which is increased upon shift of major lobe 60, namely, the righthand first minor lobe 62, assumes a position closer g to the axis 8 of the maximum lobe i6 and therefore interacts, as is desired, with a portion of the maximum lobe 16 having a high amplitude.
  • the left-hand minor lobe 62 having a decreased amplitude assumes a position far- 16 ther away from axis .9 and therefore interacts, as is desired, with a portion of maximum lobe 76 having a low amplitude.
  • first minor lobes ,62 increases in intensity and climbs cellation occurs and the firstuninor lobes 62 are eliminated or at least materially reduced.
  • the right or high first minor lobe 62 extends above, and the left or low' first minor lobe 62 Just reaches, the maximum lobe 16.
  • the attenuator 69 is adjusted to a value at which both first minor lobes 92 are reduced to a compromise value.
  • the left or low minor lobe 92, and the maximum lobe I6 in antiphase therewith combine to produce the fiat null 19 ofthe resultant pattern 17.
  • the right or high first 3o minor lobe 62, and the maximum lobe 16 in antiphase therewith combine to produce the sharp null 90 and the pip or first subsidiary lobe 6! of the resultant pattern Ti.
  • the maximum amplitude of the major lobe 52 is Em whereas the maximum amplitude of the principal 4 4 tem, as obtained with the auxiliary antenna syslobe 69 is Em-l-Ea so that, although minor lobes 56, 57 and 58 do not interact with the maximum lobe 67, the maximum amplitudes ofthe subsidiary lobes ll, 12 and 19 are each only a small percentage of the resultant principal lobe 69, whereas the maximum amplitude of the corresponding minor lobe is a somewhat larger percentage of the major lobe 52.
  • 83 and 84 are each a relativel small percentage of principal lobe 18, whereas the maximumamplitudes of minor lobes 64, 65 and 66. are each a somewhat larger percentage of the major lobe 6D.
  • Fig. 60 for both the on-axis condition, Fig. 4, and the off-axis condition, Fig. 60
  • the auxiliary antenna functions to reduce materially or obliterate the first minor lobes of the main antenna pattern or, in other words, to produce in cooperation with the main antenna system a resultant pattern having atthe positions of the first minor lobes very insignificant subsidiary lobes, the maximum amplitudes of which are determined primarily by the ratio of the amplitudes of the higher order minor lobes and the maximum amplitude, not of the major lobe, but
  • the auxiliary antenna produces a resultant principal lobe having a high ain, as measured along. the axisof the principallobe.
  • Fig. 6 illustrates the E-plane resultant pattern when the beam is" switched up (or down) or, stated difierently, when the resultant principal lobe is on-axis in the E-plane and oilaxis inthe H-plane.
  • Fig. 7 illustrates the E-plane resultant pattern when the beam is switched left (or right) or, stated differently, when the principal lobe is off-axis in the E-plane and on-axis in the H-plane.
  • Fig. 6 illustrates the E-plane resultant pattern when the beam is" switched up (or down) or, stated difierently, when the resultant principal lobe is on-axis in the E-plane and oilaxis inthe H-plane.
  • Fig. 7 illustrates the E-plane resultant pattern when the beam is switched left (or right) or, stated differently, when the principal lobe is off-axis in the E-plane and on-axis in the H-plane.
  • FIG. 8 illustrates ,the H-plane resultant Dattem when thebeam is lobed left (or right), that is, when the principal lobe is on-axis in the H-plane and oiT-axisin the E- plane.
  • Fig. 9 illustrates the H-plane resultant pattern when the beam is lobed up (or down) that is, when the principal lobe is off-axis in the Roughly,
  • the maximum amplitudes of the first minor lobes 91 are about 23 per cent-of the maximum amplitude of the 11 major lobe 88.
  • the left first minor lobe 81 which on the oppositeside of axis 8'from the beam hift, has a maximum amplitude of about 43.5 ner cent and is closer to axis 8 than the.left or :orresponding first minor lobe of Fig. 6.
  • the left first mindrlobe 81 which is on the side of axis 8 opposite from, the beam shift, has a maximum amplitude of 45.7 per cent and is slightly closer to the axis 8 than the left first minor lobe 81 of Fig. 8.
  • the two minor lobes 81 which increase in amplitude increase about the same amount, that is, 48.5 and 45.7 per cent;
  • the minimum lobes I88 have, generally speaking, a maximum amplitude of about21 per cent of the maximum amplitude of the maximum lobe 88 and about 6 per cent of the principal lobe I8I of the resultant pattern 8I. Hence; as is desired, these minimum lobes I88 are almost negligible. If desired, the minimum lobes I88 may be further reduced by using more than two, for example four, properly spaced dipoles in the primary antenna 41 of the auxiliary antenna system 8 and by tapering the intensities of the dipole currents.
  • auxiliary. antenna system particularly the auxiliary reflector I8
  • the amplitude control means 48,'Fig. 2 associated with the auxiliary antenna system, is adjusted so that the maximum lobe and the enlarged first minor lobes mutually cancel.
  • a transmitting in order to compensate for the change produced in the main antenna patterns 85, 88, 81 and 88, by the blocking effect of the auxiliary reflector, a
  • the pattern 8! includes a pair of deep nulls I82 at the angular directions corresponding to'the first minor lobes 81 which, in the main antenna pattern 88, have amplitudes of 28.7 per cent.
  • the first minor lobes 81 are obliterated.
  • the subsidiary lobes I88 and I84 are about 10 per cent of the single trip or one-way resultant principal lobe II" and about 1 per cent of the calculated round-trip or two-way principal lobe which is illustrated in Fig. 12. In Fig.
  • the left first minor lobe 81 which increased with beam shift, is in effect decreased from 48.5 per cent to 13.0 per cent in the resultant pattern, corresponding'to the value of the left first subsidiary lobe I88, Fig. 7.
  • the right first minor lobe 81 of 9 per cent is decreased almost to zero as shown by the value of the right first null I82 of pattern 82, Fig. '7.
  • the right; higher order minor lobe 88, Fig. '1, of 19.5 per dent is in effect reduced to 15.2 per cent which corresponds to the value of the right first subsidiary lobe I88, while the left higher order minor lobes 88 are increased somewhat, but confined to a maximum amplitude of per cent.
  • the left and right first minor lobes 81 of pattern 81, Fig. 8, which haveamplitudes of 28.5 per cent, are in effect transformed into first subsidiary lobe's I88 having amplitudes of about 12.8 per cent.
  • first subsidiary lobe's I88 having amplitudes of about 12.8 per cent.
  • the left first minor lobe 81,'which increased to 45.8 per cent in amplitude with the lobing', is converted 'to the left first subsidiary lobe I88, the maximum amplitude of which is about 14.5 per cent; andthe right first minor lobe 81, which decreased to 23.8 per right first subsidiary lobe I88 having a 18.3 per cent amplitude.
  • first minor lobes 81 in the H-plane patterns are each a combination of the first and second minor lobes.
  • E-plane the first and second minor lobes have opposite phases, it has beemfound in testing one embodiment that in the H-plane the first and second' minor lobes have quadrature phases and therefore merge to form the large secondary lobes 81 which are shown in Figs. 8 and 9, and have been designated as first" minor lobes. Note that in Fig.
  • the secondary lobes 81 are, at the 70 :18 degree peak amplitude, reduced to zero or nulls I 82in the resultant pattern, but that fairly prominent first subsidiary lobes I88 are aligned with certain off-axis or off-peak directions included in the secondary lobes 81 and having minor amplitude values.
  • the presence of the relatively the blocking action of the auxiliary antenna system 8 causes.
  • cent in amplitude is in effect changed to-the*
  • the maximum lobe 89 of the auxiliary antenna is merging with the second minor lobe 98 (not shown) which is in phase quadrature with the maximum lobe.
  • Figs. 6 and 7 substantially complete elimination of the first minor lobes 91 is efiected, in the H-plane, the reduction is not entirely complete. If only the directive operation in the H-plane is of interest, a compromise phase adjustment of the auxiliary antenna system may be made for the purpose of further decreasing the H-plane secondary lobes 91.
  • E-plane at the half power or 50 per cent point of the principal and major lobes, the increase is from 12 to 13.5-degrees or about 12.5 per cent.
  • the increase in main beam width at the half power point is from 13.9 to 15.6 degrees or 12.5 per cent.
  • this increase in width is relatively small as compared to the to per cent increase in main beam width produced by the prior art method of minor lobe reduction which involves tapering the illumination of a reflector.
  • Such an increase in the beam width is not desired, particularly because the gain of the antenna, for a given aperture, is reduced.
  • the region close to the main beam is almost free of radiation.
  • false crossovers cannot occur between'the main beam and the first minor lobes; and, as is desired, the only crossover is on axis 6 and between the two main beam positions.
  • the true or desired crossover is the point on axis 8 at which the resultant lobe, in its up position, intersects the resultant lobe, in its down position.
  • the true crossover occurs on axis 6.
  • a false crossover occurs only 11 degrees from and on each side of axis 8.
  • the false crossover is between the major lobe and the first minor lobe and its amplitude is about 38.5 per cent one way. Another false crossover occurs at i 26 degrees with an amplitude of 23 per cent one way.
  • the false crossovers may produce, of course, false or ambiguous indications'on the train (rightleft) indicator or the elevation (up-down) indicator in the radar transceiving device 28.
  • the maximum false crossover amplitude is relatively low, namely, 8.2 per cent one way.
  • Figs. 10, 11 and 12 were obtained by calculating the echo amplitude received after reflection by a distant target.
  • Figs. 10 and 11 illustrate the E-plane and H- plane resultant patterns, respectively, when the beam is lobed to the right position: and
  • Figs. 12 and 13 illustrate the E-plane andH-plane patterns. respectively, when the beam or resultant lobe is switched to the up position.
  • the E-plane and H-plane patterns of Figs. 10 and 11 are eachreversed: and when the beam is lobed to the down position, the E-plane and H-lplane patterns of Figs. 12 and 13 are each reversed.
  • the reference numeral I05 denotes the resultant pattern for the system'oi' the invention comprising a main antenna system and an auxiliary antenna system 9 and numeral I66 denotes the patterns for the main antenna system I taken alone.
  • Numerals I01 denote the principal lobe
  • numerals I08 t e first nulls
  • numerals I09 the subsidiary lobes of the resultant patterns I06.
  • Numerals IIO denote the major lobes and numerals II I the first minor lobes of the main antenna patterns I06.
  • the maximum amplitude of the first minor lobes III for these two pattern-s is 19.2 per S0 tude from about 84-, to V42 of the maximum inmum intensity of the first minor lobes III is about 20.8 per cent and the auxiliary antenna reduces this intensity to 2.1 per cent, that is, from about V5 to about ,3 of the maximum intensity of the principal lobe III'I.
  • y the maximum amplitude of the first minor lobes III for these two pattern-s.
  • the first minor lobes III are completely eliminated or substantially reduced.
  • the main antenna may be disconnected from de vice 28 by suitable switching and the auxiliary antenna may be utilized as a "search" antenna for roughly locating the target direction. After the search operation is completed. the two systems may then be utilized for-accurate dual plane lobe switching.
  • a method of reducing or obliteratin at least one minor lobe in an antenna direc ive characteristic which comprises aligning a direction of action of a lobe of another directive character-let's with the direction of, maximum action or axis of said minor lobe, substantially equal zing the two lobe intensities. and rendering said lobes antiphasal.
  • a method of materially reducing at least one minor lobe in the directive pattern of a main antenna system which comprises align ng a direction of action in the maximum lobe of. an auxiliary antenna-with the direction of maximum action of said minor lobe, substantially equalizing the intensities of said lobes in-the aligned directions, and rendering said lobes antiphasal.
  • a method of reducing the two cop hasal first minor lobes flanking the major lobe in the directive characteristic of a main antenna system.
  • an auxiliary antenna having a maximum lobe the angular width of which is at least as great as the combined angular width of the three flrstmentioned lobes, which comprises aligning the direction of greatest action oi said maximum lobe with a direction included in said major lobe. substantially equalizing the intensities of said maximum lobe and said minor lobes, and rendering .said maximum lobe'and said minor lobes antiphasal.
  • a pair of antenna systems connected through separate, lines to the same translation device, one of said antenna systems v having a minor directive lobe and the other antenna system having a maximum directive lobe. a direction of action in said maximum lobe being aligned with the axis or direction of greatest action in said minor lobe, a phase shifter included 6.
  • a pair of antenna systems connected through separate, lines to the same translation device, one of said antenna systems v having a minor directive lobe and the other antenna system having a maximum directive lobe. a direction of action in said maximum lobe being aligned with the axis or direction of greatest action in said minor lobe, a phase shifter included 6.
  • one of said antenna systems having a major directive lobe interposed between a pair of cophasal directive minor lobes and having a phase opposite that of said minor lobes, the other antenna system having a maximum directive lobe aligned with said major lobe, the width of said maximum lobe being substantially equal to the combined widths of said major lobe and-said minor lobes, and means comprising a phase shifter and an attentuator included in one of said lines (or rendering said maximum lobe and saidminor lobes antiphasal and for equalizing substantially said maximum lobe and said minor lobes.
  • a translation device comprising a pair of parabolic reflectors, separate primary antennas at the fool of said reflectors, a flrst line connecting said primary antennas to said device, an auxiliary antenna system comprising a parabolic reflector, a separate primary antennaat its focus, a second line connecting said last-mentioned primary antenna to said device, said three reflectors facing the, same direction and having parallel axes included in the same plane.
  • the aperture dimension in said plane oi each of the main antenna reflectors being greater than the aperture dimansion in said plane oi.
  • the directive pattern of the'main antenna in a plane of radio action perpendicular to the first-mentioned plane including a narrow 'major lobe interposed between a pair of cophasal minor lobes having a phase opposite to that of the major lobe, and the directive pattern of the auxiliary antenna in said plane of action being the two minor lobes substantially equal to the intensities of said minor lobes.
  • main antenna system comprising a pair of parallel linear arrays each comprising a plurality of spaced antenna elements, a first line connecting all 01' said elements to said device, an auxiliary antenna system comprising a linear array of elements, a-second line connecting the last-mentioned elements to said device, the plurality of elements in each of the two first-mentioned arrays being greater than the plurality of elements inthe last-mentioned array, said main antenna having in one plane of radio action a directive pattern including a narrow major lobe interposed between two cophasal minor lobes, the phase of the minor lobes being different from that of the major lobes, and the directive pattern of said auxiliary antenna in said plane or action being aligned substantially with the first-mentioned directive pattern and including a maximum lobe having a width substantially equal to the combined widths of said major lobe and said minor lobes.
  • a main antenna system and an auxiliary antenna each comprising a cylindrical parabolic reflector, said reflectors iacing in the same direction and having parallel axes, the width and length dimensions of the main reflector being greater than the corresponding dimensions of the auxiliary reflector, separate primary antennas for said reflectors each comprising a linear array of antenna elements aligned with the reflector focal line, the plurality of elements in the primary antenna of the main system being greater than the plurality of elements in the primary antenna of the auxiliary system, and means-for simultaneously connecting all of said elements to a translation device. 16. In a dual plane lobe switching system. a
  • main directive antenna system comprising a large upper cylindrical parabolic reflector and a large lower cylindrical parabolic reflector, a pair of linear subarrays aligned with the focal line of each reflector and each comprising a plurality of dipoles, a translation device, separate lines connecting the four subarrays to said device, means connected to said lines for shifting the phase of the currents in two of said lines simultaneously and in all of said lines successively, an auxiliary directive antenna system positioned adjacent to said main system and comprising a small cylinattenuator, an, adjustable phase changer, said changer.

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  • Variable-Direction Aerials And Aerial Arrays (AREA)
US568248A 1944-12-15 1944-12-15 Directive antenna system Expired - Lifetime US2458885A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US568248A US2458885A (en) 1944-12-15 1944-12-15 Directive antenna system
GB28972/46A GB624876A (en) 1944-12-15 1946-09-27 Improvements in aerial systems
FR934847D FR934847A (fr) 1944-12-15 1946-10-15 Installation d'antennes directrices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US568248A US2458885A (en) 1944-12-15 1944-12-15 Directive antenna system

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FR (1) FR934847A (fr)
GB (1) GB624876A (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2551586A (en) * 1945-08-09 1951-05-08 Lee R Dobler Antenna system
US2570599A (en) * 1946-03-19 1951-10-09 Rca Corp Aerial array and feeder arrangement for use therewith
US2677055A (en) * 1949-10-06 1954-04-27 Philip J Allen Multiple-lobe antenna assembly
US2689305A (en) * 1945-07-09 1954-09-14 Us Sec War Antenna
US2990544A (en) * 1957-04-30 1961-06-27 Hazeltine Research Inc Radar antenna system providing improved resolution
US3158866A (en) * 1962-03-28 1964-11-24 Joseph C Powers Universally adjustable antenna support
US3281295A (en) * 1964-08-25 1966-10-25 Capucio Eugene Method of capping
US6677908B2 (en) * 2000-12-21 2004-01-13 Ems Technologies Canada, Ltd Multimedia aircraft antenna
CN106654565A (zh) * 2015-12-20 2017-05-10 中国电子科技集团公司第二十研究所 基于mimo体制相控阵的一体化超宽带偏置抛物柱面阵列天线

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1821386A (en) * 1927-10-28 1931-09-01 Rca Corp Antenna
US2095083A (en) * 1934-11-17 1937-10-05 Telefunken Gmbh Directional antenna system
DE706661C (de) * 1936-01-17 1941-05-31 Telefunken Gmbh Richtsendeanlage mit zwei voneinander unabhaengigen Richtcharakteristiken
US2342721A (en) * 1940-01-20 1944-02-29 Boerner Rudolf Parabolic reflector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1821386A (en) * 1927-10-28 1931-09-01 Rca Corp Antenna
US2095083A (en) * 1934-11-17 1937-10-05 Telefunken Gmbh Directional antenna system
DE706661C (de) * 1936-01-17 1941-05-31 Telefunken Gmbh Richtsendeanlage mit zwei voneinander unabhaengigen Richtcharakteristiken
US2342721A (en) * 1940-01-20 1944-02-29 Boerner Rudolf Parabolic reflector

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2689305A (en) * 1945-07-09 1954-09-14 Us Sec War Antenna
US2551586A (en) * 1945-08-09 1951-05-08 Lee R Dobler Antenna system
US2570599A (en) * 1946-03-19 1951-10-09 Rca Corp Aerial array and feeder arrangement for use therewith
US2677055A (en) * 1949-10-06 1954-04-27 Philip J Allen Multiple-lobe antenna assembly
US2990544A (en) * 1957-04-30 1961-06-27 Hazeltine Research Inc Radar antenna system providing improved resolution
US3158866A (en) * 1962-03-28 1964-11-24 Joseph C Powers Universally adjustable antenna support
US3281295A (en) * 1964-08-25 1966-10-25 Capucio Eugene Method of capping
US6677908B2 (en) * 2000-12-21 2004-01-13 Ems Technologies Canada, Ltd Multimedia aircraft antenna
CN106654565A (zh) * 2015-12-20 2017-05-10 中国电子科技集团公司第二十研究所 基于mimo体制相控阵的一体化超宽带偏置抛物柱面阵列天线

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FR934847A (fr) 1948-06-02
GB624876A (en) 1949-06-17

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