US2548655A - Directive dielectric guide antenna - Google Patents

Directive dielectric guide antenna Download PDF

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Publication number
US2548655A
US2548655A US665027A US66502746A US2548655A US 2548655 A US2548655 A US 2548655A US 665027 A US665027 A US 665027A US 66502746 A US66502746 A US 66502746A US 2548655 A US2548655 A US 2548655A
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United States
Prior art keywords
horn
plane
guide
mode
modes
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Expired - Lifetime
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US665027A
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English (en)
Inventor
Cassius C Cutler
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AT&T Corp
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Bell Telephone Laboratories Inc
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Filing date
Publication date
Priority to BE472577D priority Critical patent/BE472577A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US665027A priority patent/US2548655A/en
Priority to FR943949D priority patent/FR943949A/fr
Priority to GB10376/47A priority patent/GB644376A/en
Priority to DEP28883A priority patent/DE826317C/de
Application granted granted Critical
Publication of US2548655A publication Critical patent/US2548655A/en
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Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/02—Waveguide horns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/10—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces
    • H01Q19/12—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave
    • H01Q19/13—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using reflecting surfaces wherein the surfaces are concave the primary radiating source being a single radiating element, e.g. a dipole, a slot, a waveguide termination
    • H01Q19/134—Rear-feeds; Splash plate feeds

Definitions

  • FIG. 5 is a diagrammatic representation of FIG. 5.
  • This invention relates to directive antenna systems and particularly to directive horn antennas.
  • a sectoral horn flared in the I-I-plane has, by reason of symmetry, no even order modes, but may have several odd modes such as the TEIO, TEso and TE50 modes; and these modes may have unfavorable phase and amplitude relations at the mouth aperture.
  • the sectoral horn heretofore employed for energizing a fan-beam passive member such as a rectangular or elliptical paraboloidal reflector, has two separated phase centers or 001 and hence the phasing at the mouth aperture is distorted. More specifically, the focus in the plane of the long mouth aperture dimension of the sectoral horn is at the throat aperture, whereas the focus in the plane of the short mouth aperture dimension is at the mouth aperture and,
  • a box or unflared horn antenna comprises a rectangular dielectric guide having at one end a large horn mouth aperture and at the other end a wall containing an iris constituting a throat aperture.
  • a small rectangular guide connects the throat'aperture to a transmitter or receiver.
  • the H-plane transverse dimension of the small guide is sufficiently narrow to permit only the TE10 mode, whereas the corresponding dimension of the large guide is wide enough to support both the T1210 and the TE30 modes.
  • the actual length of the large guide and the ratio of the H-plane dimensions of the guides. are critically selected, such that the two modes combine in the horn mouth aperture to produce a substantially fiat wave front.
  • Fig. 1 is a perspective view of a box or twomode horn antenna constructed in accordance with the invention
  • Figs. 2, 3 and 4 are mode diagrams, and Fig. 5 is an amplitude curve, all used in explaining the embodiment of Fig. 1;
  • Fig. 6 is a perspective view of another embodiment of the invention.
  • Fig. 7 is a perspective view of an embodiment of the invention comprising a fan-beam reflector and a front feed dual-mode horn;
  • Fig. 8 is an H-plane sectional view of the front feed two-mode 0r dual-mode horn utilized in the system of Fig. 7;
  • Figs. 9 and 10 are measured directive. patterns for the system of Fig. I;
  • Fig. 11 is a perspective View of an embodiment of the invention comprising a fan-beam reflector and a rear feed dual-mode horn;
  • Figs. 12 and 13 are, respectively, E-plane and H-plane sectional views of the rearfeed dualmode horn employed in the system of Fig. 11, and
  • Figs. 1 4 and 15 are measured directive patterns for the system of Fig. 11. a
  • the wave and mode symbols, for example, the symbol T Em, usedherein are the same as those given on page 395 of the textbook Electromagnetic Waves" by S. A. Schelkunoff and now more or less universally adopted in the art. Formerly, TE and TM waves were designated H and E waves, respectively.
  • reference numeral I denotes a translation device, such as a transmitter or a receiver
  • numeral 2 designates arelatively small open ended rectangular dielectric guide connected thereto and having an axis 3.
  • the guide 2 comprises two narrow parallel longitudinal metallic walls 4, 5, two wide metallic longitudinal walls 6, 1 and the dielectric medium 8 bounded by the aforesaid four walls.
  • the particular medium utilized in the embodiment of Fig. l is air but, as is well known, other dielectric substances, such as solid dielectric material, may be employed'in place of the air dielectric.
  • the narrow walls 4, 5 are parallel to the electric polarization E, and hence perpendicular to the magnetic polarization H, of the TE waves conveyed by the guide or, stated diiierently, walls 4, 5 and walls 6, I are parallel to the E-plane and the H-plane, respectively.
  • Numeral 9 denotes a dual-mode box horn comprising a relatively large rectangular dielectric guide having a longitudinal axis 3, narrow longitudinal E-plane walls [0, wide longitudinal H- plane walls I I, an open end l2 constituting a horn mouth aperture and an end orthroat wall 13 having a central iris l4 constituting a throat aperture.
  • the dual-mode horn 9 is directly connected to guide 2, the iris M and the open end of guide 2 being coincident.
  • the walls 4 and I have equal transverse E- plane dimensions, 0, whereas the transverse H- plane' dimension, 1111, of guide 2 is smaller than the-corresponding dimension, 1.02, of the horn 9.
  • the dimensions 101 and we each have, preferably but not necessarily, minimum and maximum values, as measured in wavelengths, M, in the air dielectric medium 8, that is, in free space; the ratio of the aforesaid dimensions being judiciously chosen, and the axial length, L, of the dual-mode horn 9 being critically selected.
  • the dimensions 201 and um are preferably chosen in accordance with the following relations:
  • the horn 9 will support higher modes, such as the amplitude of mode 15.
  • the horn mouth aperture the horn 9 must be properly dimensioned. Even order H-plane modes, such as the TEzo mode, are not excited in either the guide 2 or horn 9, inasmuch as these dielectric paths are symmetrical about an E- plane containing the axis 3. Also so that a complet E-plane mode is not supported in guide 2 or horn 9.
  • H-plane modes such as the TEzo mode
  • a TE-lO wave mode l5 of relatively large amplitude in guide 2, Fig. 2 enters the dual-mode horn 9 through the throat aperture l 4 and produces at the junction or throat wall i3 a TE10 mode I6, of smaller amplitude, Fig. 3, and, by reason of the value of dimension we and the abrupt expansion (uh to we) in the I-I-plane dimension, initiates a TEso mode H of small amplitude. Since modes l6 and I!
  • the modes [6 and H are oppositely phased.
  • A1 is the amplitude of the 'I'Elio mode [6
  • A3 is the amplitude of the TEso'mode H
  • A is the amplitude ratio of the two modes so that at throat I3 the wave front H3 in the H- plane, Fig. 3, resulting from the algebraic addition of modes 1% and I1, is curvilinear rather than linear.
  • the wave is convex rather than fiat.
  • V1 Vfi (10)
  • M is the guide wavelength at the TEio mode l6
  • A3 is the guide wavelength at the 'IEso mode ll.
  • the amplitudes A1 and A3, and the amplitude ratio A may be obtained by making a Fourier analysis of the incident field at the junction l3 and considering only the first two terms.
  • R and A may each have any practical value greater than zero and less than unity, a value of R in the order of 0.4 to 0.8, corresponding to a value of A in the order of 0.7 to 0.2, is particularly satisfactory.
  • the operation is, by reason of the reciprocity theorem, the converse of the transmitting operation.
  • the incoming wave establishes similarly phased TEIO and TEco modes in the horn mouth aperture l2. By reason of the horn length L, these modes are rendered in opposite phase at the throat aperture 14 and a. strong TE'm wave is initiated in guide 2 and conveyed to the receiver 1.
  • the narrow walls I0 of the dual mode, horn 9 may be flared and, also if desired, the wide walls ll may be flared.
  • the flaring may be advantageously utilized to secure optimum energization of the passive member.
  • the antenna system 20 comprises a quasi-elliptical paraboloidal reflector 2
  • the quasi-elliptical contour of the reflector eliminates the so-called corner minor lobes which are present in the pattern of the conventional rectangular parabolic reflector.
  • Numeral 23 denotes the axi of the reflector 2
  • the horn 22 has a mouth aperture 24 and is connected through an iris 25 to a front feed dielectric guide 26.
  • the E-plane dimension of the iris 25 is slightly less than the E-plane dimensionof guide 26.
  • the H-plane dimension, 101, of iris 25 and the I-l-plane dimension, we, of the horn 22 are properly selected, as explained in connection with Fig. 1.
  • Guide 26 is connected to a translation device I which serves as a support for the reflector 2!.
  • a dielectric window 2! is positioned near the mouth aperture 24 of the dual-mode horn 22 and is rigidly secured to the horn by means of the metallic members 28 and the bolts 29.
  • Numeral 3! denotes a tuning plug in guide 26 and numeral 3
  • the reference letter L denotes the actual length of the dual mode horn 22.
  • the phase velocity in air is different from that in the window so that, if the window is thick, this difference must be taken into account in determining the value of L.
  • the window is usually relatively thin so that the above-mentioned difference in velocities may be disregarded in determining L.
  • a TEm mode is produced in guide 2 by device I and the energy, after passing through the iris 25, appears in the horn 22 in the form of the two modes T1310 and TEso.
  • the two modes produce a flat front in the mouth aperture of the dual mode horn 22. Since the wave front in the mouth aperture is airisto minor axis, for example, 1:3 to 1 :5.
  • the front of the wave arriving at the reflector is fairly spherical, as is desired.
  • the mouth aperture simulates a point source.
  • the beam produced by the dualmode horn 22 is of the horizontal fan-beam type, the beam being wider in the E-plane than in the-H-plane, and therefore suitable for illuminating in an optimum manner the quasi-elliptical reflector 2
  • the shape of the wave front impinging upon the reflector is dependent primarily upon the relative phasing of the diverse wavelets forming the front, whereas the shape of the beam is dependent primarily on the relative amplitudes of the wavelets.
  • reference numerals 32 and 33 denote, respectively, the measured Eplane and H-plane directive patterns of a front-fed dual-mode horn 22 actually constructed and tested at a design wavelength of 3.2 centimeters.
  • Numerals 34 and 35 denote, respectively, the measured E-plane and H-plane patterns for the complete system comprising a born 22 and a quasi-elliptical reflector 2
  • numeral 35 denotes the major lobe
  • numerals 3T designate the minor lobes
  • numerals 38 denotes the half power angular width of the major lobe. As shown in Fig.
  • the half power widths 38 of the major lobes 36 in the E-plane and I-I-plane patterns 32 and 33 are respectively about '70 and 21 degrees and hence, as stated above, the beam of the horn is of the fan type. As compared to the fan-beams of feed horns of the prior art, the fan-beam is more pronounced, that is, the lobe width ratio is greater. Hence the dualmode horn is especially suitable for use with an elliptical reflector having a pronounced fanbeam characteristic, that is, an elliptical reflector having a relatively large ratio of major The minor lobes 3'! of the horn patterns 32 and 33 are at least decibels down and therefore negligible. As shown in Fig.
  • the half power 'widths 38 of major lobes 35' of the E and H- plane patterns 34 and 35, for the entire system, are 2.2 and 5 degrees, respectively, and the beam
  • the reflector fanbeam Fig. is in a sense the converse of the horn fan-beam, Fig. 9, since in Fig. 9 the beam is wide in the E-plane and narrow in the H- plane whereas, in Fig. 10, the beam is narrow in the E-plane and wide in the H-plane.
  • the antenna system 40 comprises a quasi-elliptical reflector 2
  • is positioned at the focus of the reflector and is connected to a rear feed dielectric guide 42 having an H-plane dimension, 201.
  • encloses the open end of guide 42 and comprises the three brass plates 43, 44 and 45, the rubber gasket 46, the dielectric plate 5'! and the brass plate 48, all held securely by brass screws 5
  • Numeral 54 denotes a threaded plug for tuning the chamber 50
  • numerals 55 denote reflective wedges positioned in slots 56 and attached to the top and bottom walls of guide 26.
  • the critical horn length L extends from the open guide end .or throat aperture to the mouth aperture 53.
  • the length L as measured in guide Wavelengths for the TEm mode dilfers a half wavelength, or a multiple thereof, from the length as measured in guide wavelengths for the T1530 mode.
  • a TEm mode is produced in guide 52 and the energy, after passing through the iris or open end, appears in each of guides 5
  • the two modes produce a substantially flat wave front in each of the two horn mouth apertures 53, and a spherical Wave front is projected toward thereflector 25.
  • the wedges 55 function to direct the wavelets emitted by the apertures toward the outermost or central peripheral portions of the left-half and the right-half of the reflector 2
  • reference numerals 5i and 58 denote, respectively the measured E-plane and H-plane directive patterns of a-rear feed dual-mode horn 4
  • the half -power widths 38 of the major lobes of the E-plane and H-plane dual-mode patterns 5'? and 58 are, respectively, about 20 and 50 degrees, respectively, and the horn beam is of the fan type.
  • the minor lobes 31 of patterns 5'! and 58 are about I! decibels down and therefore negligible.
  • , Fig. 11 is especially suitable for use with an elliptical reflector having a large ratio of major axis to minor axis, for example, 113 to 1:5.
  • the half power widths 38 of the major lobes 36 of the E and I-l-plane patterns 59 and 60, for the complete system are 2 and 5.1 degrees respectively and the beam is therefore of the fan type.
  • the minor lobes 31 of patterns 59 and B0 are more than 23 decibels down and therefore negligible.
  • a box or two-mode horn for transmitting or receiving a combined TEm and TEzo wave, .said horn comprising a first dielectric guide for conveying only a TEm wave mode and a second guide connected thereto for conveying said wave ,mode and a TEao wave mode, said wave modes having different guide wavelengths, the difference between the length of said second guide as measured in guide wavelengths at one of said modes and the length of said second guide as measured in guide wavelengths at the other mode being a half wavelength.
  • a front feed two-mode horn antenna system for transmitting or receiving TE waves, said system comprising a first dielectric guide and a second dielectric guide each having E and H- plane walls, said second guide having an end wall and an iris in said end wall, said first guide being 9 electrically connected to said second guid through said iris, the I-I-plane Walls of said second guide being wider than the I-I-plane Walls of said first guide, the difference between the length of said second guide as measured in guide wavelengths for the TEM) mode and the length of said second guide as measured in guide wavelengths for the TEso mode being a half wavelength, or an odd multiple thereof.
  • a rear feed two-mode horn antenna system comprising a main dielectric guide having an open end, a resonant chamber enclosing the end of said guide, a pair ofv auxiliary guides connected to said chamber and each having an antenna aperture, said main and auxiliary guides being parallel and having given I-I-plane dimensions, the I-I-plane dimensions of said auxiliary guides being greater than that of the main guide and such as to permit the conveyance of 'IEm and TEso wave modes, the difference between the distance from said open end to each aperture as measured in guide wavelengths for the TEm mode and said distance as measured in guide wavelengths for the TEao mode being a half wavelength.
  • a paraboloidal reflector having a focal point and a quasi-elliptical periphery, the ratio of the major axis to the minor axis of said periphery being in the order of 5:1 to 3:1, a two-mode horn at said focal point for radiating or receiving a wave including a TE component and a TE'so component, a guide connecting said horn to a translation device, said horn having at least one rectangular mouth aperture facing said reflector, said horn and aperture each having an, I-I-plane dimension extending parallel to said minor axis, the axial length of said horn as measured in guide wavelengths for the TEm component being a half Wavelength different from said length as measured in guide wavelengths for the TE30 component.
  • a paraboloidal reflector having a focal point and a quasi-elliptical periphery, an unflared dual-mode horn at said focal point, said horn having a single mouth aperture facing said reflector and transverse E and H- plane walls, a dielectric guide having E- and H-plane walls extending across a portion of said reflector and attached to said horn, an iris in an E-plane wall of said guide for electrically connecting said guide and horn, the I-I-plane walls of said horn being wider than the I-I-plane walls of said guide and Wider than the H-plane dimension of said iris.
  • a paraboloidal reflector having a focal point and a quasi-elliptical periphery, a rectangular guide extending through said reflector and having an open end near the focus of said reflector, a resonant chamber enclosing the end of said guide, a pair of auxiliary guides connected to said chamber and each having an antenna aperture facing said reflector, the difference in the distance from said open end to each antenna aperture as measured in guide wavelengths for the TEm mode and said distance as measured in guide wavelengths for the 'IExo mode being a half wavelength or an odd multiple thereof.

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US665027A 1946-04-26 1946-04-26 Directive dielectric guide antenna Expired - Lifetime US2548655A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE472577D BE472577A (xx) 1946-04-26
US665027A US2548655A (en) 1946-04-26 1946-04-26 Directive dielectric guide antenna
FR943949D FR943949A (fr) 1946-04-26 1947-03-25 Système d'antenne directive
GB10376/47A GB644376A (en) 1946-04-26 1947-04-18 Directive antenna systems
DEP28883A DE826317C (de) 1946-04-26 1948-12-31 Richtstrahler mit dielektrischer Wellenleitung

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US665027A US2548655A (en) 1946-04-26 1946-04-26 Directive dielectric guide antenna

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US2548655A true US2548655A (en) 1951-04-10

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US665027A Expired - Lifetime US2548655A (en) 1946-04-26 1946-04-26 Directive dielectric guide antenna

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BE (1) BE472577A (xx)
DE (1) DE826317C (xx)
FR (1) FR943949A (xx)
GB (1) GB644376A (xx)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2675524A (en) * 1948-03-25 1954-04-13 Emi Ltd Electrical wave guide provided with tuning pistons
US2692984A (en) * 1950-08-30 1954-10-26 Sperry Corp Bridge obstruction marker for radar navigation
US2778016A (en) * 1953-01-23 1957-01-15 Gabriel Co Wave guide antenna
US2809371A (en) * 1954-09-30 1957-10-08 Rca Corp Liquid trap for vertically mounted horn antenna
US10763916B2 (en) * 2017-10-19 2020-09-01 At&T Intellectual Property I, L.P. Dual mode antenna systems and methods for use therewith

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2129669A (en) * 1937-03-30 1938-09-13 Bell Telephone Labor Inc Guided wave transmission
US2206923A (en) * 1934-09-12 1940-07-09 American Telephone & Telegraph Short wave radio system
US2232179A (en) * 1938-02-05 1941-02-18 Bell Telephone Labor Inc Transmission of guided waves
US2255042A (en) * 1939-01-03 1941-09-09 Research Corp Electromagnetic horn
US2283935A (en) * 1938-04-29 1942-05-26 Bell Telephone Labor Inc Transmission, radiation, and reception of electromagnetic waves
US2396044A (en) * 1941-12-10 1946-03-05 Bell Telephone Labor Inc Switching device
US2405242A (en) * 1941-11-28 1946-08-06 Bell Telephone Labor Inc Microwave radio transmission
US2415807A (en) * 1942-01-29 1947-02-18 Sperry Gyroscope Co Inc Directive electromagnetic radiator
US2416698A (en) * 1938-04-29 1947-03-04 Bell Telephone Labor Inc Radiation and reception of microwaves

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2206923A (en) * 1934-09-12 1940-07-09 American Telephone & Telegraph Short wave radio system
US2129669A (en) * 1937-03-30 1938-09-13 Bell Telephone Labor Inc Guided wave transmission
US2232179A (en) * 1938-02-05 1941-02-18 Bell Telephone Labor Inc Transmission of guided waves
US2283935A (en) * 1938-04-29 1942-05-26 Bell Telephone Labor Inc Transmission, radiation, and reception of electromagnetic waves
US2416698A (en) * 1938-04-29 1947-03-04 Bell Telephone Labor Inc Radiation and reception of microwaves
US2255042A (en) * 1939-01-03 1941-09-09 Research Corp Electromagnetic horn
US2405242A (en) * 1941-11-28 1946-08-06 Bell Telephone Labor Inc Microwave radio transmission
US2396044A (en) * 1941-12-10 1946-03-05 Bell Telephone Labor Inc Switching device
US2415807A (en) * 1942-01-29 1947-02-18 Sperry Gyroscope Co Inc Directive electromagnetic radiator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2675524A (en) * 1948-03-25 1954-04-13 Emi Ltd Electrical wave guide provided with tuning pistons
US2692984A (en) * 1950-08-30 1954-10-26 Sperry Corp Bridge obstruction marker for radar navigation
US2778016A (en) * 1953-01-23 1957-01-15 Gabriel Co Wave guide antenna
US2809371A (en) * 1954-09-30 1957-10-08 Rca Corp Liquid trap for vertically mounted horn antenna
US10763916B2 (en) * 2017-10-19 2020-09-01 At&T Intellectual Property I, L.P. Dual mode antenna systems and methods for use therewith

Also Published As

Publication number Publication date
BE472577A (xx)
DE826317C (de) 1951-12-27
FR943949A (fr) 1949-03-22
GB644376A (en) 1950-10-11

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