US3864690A - Multifrequency operating radome - Google Patents

Multifrequency operating radome Download PDF

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Publication number
US3864690A
US3864690A US411911A US41191173A US3864690A US 3864690 A US3864690 A US 3864690A US 411911 A US411911 A US 411911A US 41191173 A US41191173 A US 41191173A US 3864690 A US3864690 A US 3864690A
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United States
Prior art keywords
network
wall
frequency
radome
discontinuous
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Expired - Lifetime
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US411911A
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English (en)
Inventor
Robert Pierrot
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Thales SA
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Thomson CSF SA
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
    • H01Q1/425—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising a metallic grid

Definitions

  • These networks of conductor wires in effect constitute a kind of grid through which the electromagnetic waves have to pass.
  • Each free space between the conductors constitutes a radiating aperture.
  • Phase distribution in the radiating apertures is not uniform since the radome is not flat and the result is accordingly a distortion in the radiation patterns of the antennas located inside the radome. This distortion is translated by the appearance of secondary lobes or grating lobes.
  • the object of the present invention is precisely that of providing a radome which does not produce such distortion.
  • the radome comprises a monolithic dielectric wall whose thickness is such that it is transparent for at least a first wave of frequency F1, a first network of continuous wires integral with the wall, designed in such a fashion that it acts in concert with said wall as an assembly resonating at a second frequency F2 lower than the frequency F1, and an assembly of discontinuous metal elements, likewise integral with the wall and distributed in accordance with the lines of a second network interleaved with said first network.
  • FIG. 1 illustrates a graph showing the transmission factor as a function of frequency, for a wall with or without metal elements
  • FIGS. 2 and 3 illustrate equivalent impedance networks for a radome comprising a network of continuous wires, at two frequencies F1 and F2 respectively;
  • FIGS. 4 and 5 represent the equivalent impedance networks of a radome comprising networks of continuous wires and discontinuous elements, for two respective frequencies F2 and F1;
  • FIG. 6 illustrates metal networks printed on a dielectric substrate.
  • FIG. 1 illustrates a graph showing the value of the transmission factor T of the wall of a radome as a function of the frequency F of a wave passing through it, and also for a given wall thickness, a given dielectric constant and a given angle of incidence.
  • the graph 1 illustrates the case of a radome which does not incorporate any metal elements.
  • the thickness appears small compared with the wavelength, and the radome behaves as a very thin skin whose attenuative effect is negligible.
  • the transmission factor is then equal to 1.
  • the factor returns to a value close to 1 whenever the thickness of the dielectric is equal to a multiple of the half wavelength in the dielectric, that is to say to a given thickness e, at the frequencies Fl, 2F1, 3F 1..
  • F1 is the frequency at which the wavelength in the dielectric is equal to twice the thickness e of the wall. It should be pointed out, too, that the pass-band at the frequencies 2Fl, 3P1, becomes progressivelynarrower.
  • the graph 2 illustrates the case of a radome comprising at least one network of wires.
  • the dielectric wall constitutes a capacitive or inductive barrier.
  • Each wire network, integral with the wall acts as barriers, of inductive or capacitive kind.
  • the combination of the wall and the wire networks constitutes therefore an assembly which resonates at a selected frequency F2 at which frequency, furthermore, the transmission factor of the wall becomes close to unity.
  • the radome is thus transparent to at least two waves, of frequencies F1 and F2. By contrast, it becomes opaque to low frequencies, the metal barriers constituting a Faraday cage. At higher frequencies, the two graphs 1 and 2 merge together.
  • FIG. 2 illustrates an equivalent impedance network corresponding to the frequency F2, for a radome equipped with a network of continuous wires.
  • the dielectric wall and the wires are equivalent from the radio point of view, respectively to a capacitance Cl and and inductance L1 in parallel with a transmission line 3 loaded at one end by the electromagnetic device operating at frequency F2, and at the other end by the space outside the radome.
  • the overcall impedance placed in parallel with the transmission line 3 is rendered infinite and the wave transmitted is unaffected.
  • the transmission factor in reality, is practically equal to l, the wall matching condition being achieved at the frequency F2.
  • the inductive element is constituted by two networks of wires at right-angles to one another, this rendering it isotropic and making it possible to install it in the radome without any problem associated with orientation of the wires.
  • FIG. 3 illustrates the equivalent of the same radome, at the frequency F1.
  • the value of the inductance L2 placed in parallel by the metal network, is much higher than it is at the frequency F2. Its effect is small and can be compensated by a slight increase in the thickness of the dielectric wall whose equivalent impedance is then that of a small capacitance C2 shunted across the input terminals of the four-terminal device Q representing the wall which is matched at frequency Fll only.
  • the radome in accordance with the invention comprises a network of continuous wires and a network of discontinuous metal elements (networks 7 and 8 shown in FIG. 6).
  • This variant embodiment has the advantage over the network of continuous wires, that it does not introduce any secondary lobes or so-called grating lobes, at the frequency F1, into the radiation pattern of the antenna protected by the radome.
  • the discontinuous metal elements can take various forms. They are arranged in lines to produce a network of parallel lines or rather two mutually perpendicular networks like the network or networks of continuous wires. The aligned sets of discontinuous elements are interposed between the continuous wires.
  • the pitch of the network of the discontinuous elements can be the same as that of the continuous wires (FIG. 6) or may be larger or smaller, depending upon the desired effect.
  • the metal elements are constituted either by segments ofwire, or by segments of metal tape of given width and thickness.
  • the network 8 is constituted by metal squares whose sides have a length of around l ⁇ /8 for the highest frequency, the pitch of the network being equal to )t/2.
  • the radome comprises continuous wires and rows of discontinuous elements, in alternation.
  • FIG. 4- illustrates the equivalent impedance network of the network and wall assembly, at the frequency F2.
  • the networks are equivalent to an inductance L3 and a capacitance C3 in parallel with a capacitance Cll representing the wall.
  • the matching conditons L3 (C1 C3)m2 l is achieved with an inductance L3 smaller than the inductance L1 in the case ofa network of continuous wires only.
  • the inductance L3 is made smaller by reducing the pitch interval of the network of wires. It is possible in this fashion to reduce the pitch sufficiently to prevent the development of grating lobes at the frequency Fl.
  • FIG. 5 illustrates the equivalent impedance networks the frequency Fl.
  • the network is again equivalent to an inductance L4 of high value and to a capacitance C4 of low value, shunted across the terminals of the matched fourterminal device representing the wall.
  • L4C4wl l the assembly is transmission matched.
  • discontinuous metal elements introduces a capacitive impedance at the wall.
  • One advantage of the invention resides in the fact that the dielectric wall can be transmission matched, even in the case where the wall appears as an inductive barrier at the frequency F2. It is then necessary for the network of discontinuous elements to be capable of presenting 5 an adequate capacitive impedance.
  • the design of a radome in accordance with the inven tion can be effected in various ways.
  • the networks of continuous and discontinuous metal elements are first of all etched, printed, stuck or deposited by vaporisation, on a dielectric substrate (for example a substrate of polyethyleneterephthalate) which will subsequently form an integral part of the wall of the radome.
  • the wall itself is made of ceramic or of some refractory material or again of resin-impregnated fibreglass.
  • the radome is manufactured by arranging on a mould a tissue of fibreglass which is stiched and then impregnated with resin. Another method consists in weaving or winding the glass fibres directly on to the mould, this avoiding the need for stiching. Generally, several layers of impregnated tissue or weave are required in order to achieve the desired thickness.
  • the introduction of the metallised substrate is effected prior to or during the building of the wall.
  • the substrate is then placed on the mould before the winding on or before the introduction of the glass tissue or weave. It can then be arranged between two layers of said tissue.
  • Another method consists in producing a metallised substrate which simply carries the networks of discontinuous metal elements. Independently the network of continuous wires is incorporated in the radome wall during the building up of same. Then the metallised substrate and the radome are joined. In the case of a radome which already contains a network of continuous wires, a substrate metallised with a network of discontinuous elements and produced in the same mould as that used for the radome, is stuck to the interior of the latter.
  • the introduction of the substrate can be effected after the building of the wall.
  • the metallised substrate is stuck to the interior of the radome. Its assembly is a relatively simple matter if the ogival shape is not too different from that of a cone, and this is generally the case.
  • a multifrequency operating radome comprising:
  • a monolithic dielectric wall for transmitting a first wave of a first frequency and its harmonics
  • a first network of continuous wires said network being integral with said wall, for constituting with said wall an assembly tuned for a second wave to a second frequency lower than the first frequency, said network being the origin of grating lobes at the first frequency, and,
  • the network of continuous wires and the network of discontinuous elements are printed on a dielectric substrate, said substrate subsequently being stuck to the internal face of the dielectric wall.
  • each of the discontinuous metal elements is constituted by a segment of wire of short length, compared with the shortest operating wavelength.
  • a multifrequency operating radome comprising:
  • a monolithic dielectric wall for transmitting a first wave of a first frequency and its harmonics
  • a first network of continuous 'wires said network being integral with said wall, for constituting with said wall an assembly tuned for a second wave to a second frequency lower than the first frequency, said network being the origin of grating lobes at the first frequency, and,
  • the network of continuous wires and the network of discontinuous elements are printed on a dielectric substrate, said substrate subsequently being incorporated into the thickness of the dielectric wall.
  • a multifrequency operating radome comprising:
  • a monolithic dielectric wall for transmitting a first wave of a first frequency and its harmonics
  • a first network of continuous wires said network being integral with said wall, for constituting with said wall an assembly tuned for a second wave to a second frequency lower than the first frequency, said network being the origin of grating lobes at the first frequency, and,
  • said dielectric wall comprises at least one tissue of glass fibres, the network of continuous wires being incorporated into the tissue during the weaving stage, and the network of discontinuous metal elements being printed on a dielectric substrate which is subsequently stuck to the internal face of the dielectric wall.
  • a multifrequency operating radome comprising:
  • a monolithic dielectric wall for transmitting a first wave of a first frequency and its harmonics
  • a first network of continuous wires said network being integral with said wall, for constituting with said wall an assembly tuned for a second wave to a second frequency lower than the first frequency, said network being the origin of grating lobes at the first frequency, and, r
  • said dielectric wall comprises at least one tissue of glass fibres, the network of continuous wires being incorporated into the tissue during the weaving of the same, and the network of discontinuous metal elements being printed on a dielectric substrate which is subsequently incorporated into the thickness of the dielectric wall.
  • each of the discontinuous metal elements is constituted by a segment of wire of short length, compared with the shortest operating wavelength.

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US411911A 1972-11-03 1973-11-01 Multifrequency operating radome Expired - Lifetime US3864690A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7238959A FR2205754B1 (de) 1972-11-03 1972-11-03

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US3864690A true US3864690A (en) 1975-02-04

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US (1) US3864690A (de)
DE (1) DE2354754C2 (de)
FR (1) FR2205754B1 (de)
GB (1) GB1396675A (de)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961333A (en) * 1974-08-29 1976-06-01 Texas Instruments Incorporated Radome wire grid having low pass frequency characteristics
US4476471A (en) * 1981-02-09 1984-10-09 Nippon Electric Co., Ltd. Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
US4775866A (en) * 1985-05-18 1988-10-04 Nippondenso Co., Ltd. Two-frequency slotted planar antenna
US4797683A (en) * 1986-10-01 1989-01-10 United Technologies Corporation Multi-spectral radome
US5384575A (en) * 1988-09-26 1995-01-24 Hughes Aircraft Company Bandpass frequency selective surface
US5455594A (en) * 1992-07-16 1995-10-03 Conductus, Inc. Internal thermal isolation layer for array antenna
US5497169A (en) * 1993-07-15 1996-03-05 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Wide angle, single screen, gridded square-loop frequency selective surface for diplexing two closely separated frequency bands
US5579024A (en) * 1984-08-20 1996-11-26 Radant Systems, Inc. Electromagnetic energy shield
US5652631A (en) * 1995-05-08 1997-07-29 Hughes Missile Systems Company Dual frequency radome
EP0803931A2 (de) * 1996-04-25 1997-10-29 Construcciones Aeronauticas, S.A. In Luftraumstrukturen für Telekommunikationen eingezogene reflektierende Elemente
US20030034933A1 (en) * 2001-08-17 2003-02-20 Anafa-Electromagnetic Solutions Ltd. Electromagnetic window
EP1508940A1 (de) * 2003-08-19 2005-02-23 Era Patents Limited Strahlformer mit Reaktanzen auf einer dielektrischen Oberfläche
WO2014065935A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with compressed grid
US20140118217A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with embedded gridded structures
CN104901008A (zh) * 2014-03-04 2015-09-09 波音公司 防雷天线罩系统
JP2015200512A (ja) * 2014-04-04 2015-11-12 株式会社日本自動車部品総合研究所 レーダ装置
US20170201017A1 (en) * 2013-11-11 2017-07-13 Gogo Llc Radome having localized areas of reduced radio signal attenuation

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2432776A1 (fr) * 1978-08-04 1980-02-29 Lignes Telegraph Telephon Reflecteur passif pour onde polarisee circulairement a grande ouverture angulaire
GB2130799A (en) * 1982-11-18 1984-06-06 Secr Defence Structural member for radar apparatus
FR2539245A1 (fr) * 1983-01-06 1984-07-13 Bruguet Jean Louis Ecran de terre a base de materiaux composites
US4638324A (en) * 1984-12-10 1987-01-20 Hazeltine Corporation Resistive loop angular filter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US3148370A (en) * 1962-05-08 1964-09-08 Ite Circuit Breaker Ltd Frequency selective mesh with controllable mesh tuning
US3560986A (en) * 1969-02-24 1971-02-02 Brunswick Corp Radar antenna radome construction
US3633206A (en) * 1967-01-30 1972-01-04 Edward Bellamy Mcmillan Lattice aperture antenna

Family Cites Families (4)

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Publication number Priority date Publication date Assignee Title
US2841786A (en) * 1956-02-03 1958-07-01 Robert H Dicke Dielectric structures
FR1492106A (fr) * 1966-04-28 1967-08-18 Thomson Houston Comp Francaise Perfectionnements aux antennes d'émission
FR1560520A (de) * 1968-01-24 1969-03-21
FR2181577B1 (de) * 1972-04-28 1974-07-26 Bony Gilbert

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US3148370A (en) * 1962-05-08 1964-09-08 Ite Circuit Breaker Ltd Frequency selective mesh with controllable mesh tuning
US3633206A (en) * 1967-01-30 1972-01-04 Edward Bellamy Mcmillan Lattice aperture antenna
US3560986A (en) * 1969-02-24 1971-02-02 Brunswick Corp Radar antenna radome construction

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961333A (en) * 1974-08-29 1976-06-01 Texas Instruments Incorporated Radome wire grid having low pass frequency characteristics
US4476471A (en) * 1981-02-09 1984-10-09 Nippon Electric Co., Ltd. Antenna apparatus including frequency separator having wide band transmission or reflection characteristics
US5579024A (en) * 1984-08-20 1996-11-26 Radant Systems, Inc. Electromagnetic energy shield
US4775866A (en) * 1985-05-18 1988-10-04 Nippondenso Co., Ltd. Two-frequency slotted planar antenna
US4797683A (en) * 1986-10-01 1989-01-10 United Technologies Corporation Multi-spectral radome
US5384575A (en) * 1988-09-26 1995-01-24 Hughes Aircraft Company Bandpass frequency selective surface
US5455594A (en) * 1992-07-16 1995-10-03 Conductus, Inc. Internal thermal isolation layer for array antenna
US5497169A (en) * 1993-07-15 1996-03-05 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Wide angle, single screen, gridded square-loop frequency selective surface for diplexing two closely separated frequency bands
US5652631A (en) * 1995-05-08 1997-07-29 Hughes Missile Systems Company Dual frequency radome
EP0803931A2 (de) * 1996-04-25 1997-10-29 Construcciones Aeronauticas, S.A. In Luftraumstrukturen für Telekommunikationen eingezogene reflektierende Elemente
EP0803931A3 (de) * 1996-04-25 1998-08-05 Construcciones Aeronauticas, S.A. In Luftraumstrukturen für Telekommunikationen eingezogene reflektierende Elemente
US20030034933A1 (en) * 2001-08-17 2003-02-20 Anafa-Electromagnetic Solutions Ltd. Electromagnetic window
EP1421646B1 (de) * 2001-08-17 2005-01-26 Anafa-Electromagnetic Solutions Ltd Elektromagnetisches fenster
US6897820B2 (en) * 2001-08-17 2005-05-24 Anafa-Electromagnetic Solutions Ltd. Electromagnetic window
WO2005020372A1 (en) * 2003-08-19 2005-03-03 Era Patents Limited Radiation controller including reactive elements on a dielectric surface
US20070176846A1 (en) * 2003-08-19 2007-08-02 Era Patents Limited Radiation controller including reactive elements on a dielectric surface
EP2077603A3 (de) * 2003-08-19 2009-07-22 ERA Technology Limited Dielektrische Leckwellenantenne
EP1508940A1 (de) * 2003-08-19 2005-02-23 Era Patents Limited Strahlformer mit Reaktanzen auf einer dielektrischen Oberfläche
US9231299B2 (en) * 2012-10-25 2016-01-05 Raytheon Company Multi-bandpass, dual-polarization radome with compressed grid
WO2014065935A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with compressed grid
US20140118218A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with compressed grid
US20140118217A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with embedded gridded structures
WO2014065934A1 (en) * 2012-10-25 2014-05-01 Raytheon Company Multi-bandpass, dual-polarization radome with embedded gridded structures
US9362615B2 (en) * 2012-10-25 2016-06-07 Raytheon Company Multi-bandpass, dual-polarization radome with embedded gridded structures
US20170201017A1 (en) * 2013-11-11 2017-07-13 Gogo Llc Radome having localized areas of reduced radio signal attenuation
US10862203B2 (en) * 2013-11-11 2020-12-08 Gogo Business Aviation Llc Radome having localized areas of reduced radio signal attenuation
EP2916387A1 (de) * 2014-03-04 2015-09-09 The Boeing Company Gegen Blitzeinschlag geschütztes Radom-System
CN104901008A (zh) * 2014-03-04 2015-09-09 波音公司 防雷天线罩系统
AU2014271125B2 (en) * 2014-03-04 2018-10-25 The Boeing Company Lightning protected radome system
CN104901008B (zh) * 2014-03-04 2019-04-26 波音公司 防雷天线罩系统
JP2015200512A (ja) * 2014-04-04 2015-11-12 株式会社日本自動車部品総合研究所 レーダ装置

Also Published As

Publication number Publication date
FR2205754B1 (de) 1977-04-22
DE2354754C2 (de) 1982-09-23
FR2205754A1 (de) 1974-05-31
DE2354754A1 (de) 1974-05-09
GB1396675A (en) 1975-06-04

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