EP0109186B1 - Antenna - Google Patents

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Publication number
EP0109186B1
EP0109186B1 EP83306201A EP83306201A EP0109186B1 EP 0109186 B1 EP0109186 B1 EP 0109186B1 EP 83306201 A EP83306201 A EP 83306201A EP 83306201 A EP83306201 A EP 83306201A EP 0109186 B1 EP0109186 B1 EP 0109186B1
Authority
EP
European Patent Office
Prior art keywords
resin
fibers
antenna according
average length
antenna
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP83306201A
Other languages
German (de)
English (en)
French (fr)
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EP0109186A1 (en
Inventor
Kazuharu Shimizu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toray Industries Inc
Original Assignee
Toray Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toray Industries Inc filed Critical Toray Industries Inc
Publication of EP0109186A1 publication Critical patent/EP0109186A1/en
Application granted granted Critical
Publication of EP0109186B1 publication Critical patent/EP0109186B1/en
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/364—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith using a particular conducting material, e.g. superconductor
    • H01Q1/368—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith using a particular conducting material, e.g. superconductor using carbon or carbon composite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/141—Apparatus or processes specially adapted for manufacturing reflecting surfaces
    • H01Q15/142—Apparatus or processes specially adapted for manufacturing reflecting surfaces using insulating material for supporting the reflecting surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures
    • H01Q15/16—Reflecting surfaces; Equivalent structures curved in two dimensions, e.g. paraboloidal
    • 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

Definitions

  • the present invention relates to an antenna, specifically to an antenna including a reflector having a paraboloidal front surface for use in transmission and reception of microwaves or millimeter waves, such as a parabolic antenna or a Cassegrainian antenna.
  • a parabolic antenna or a Casegrainian antenna including a reflector having a paraboloidal front surface (a radio wave reflecting surface) and a primary radiator have been known in the past.
  • Known reflectors can have a reflecting layer made of carbon fiber reinforced resin, that is (a) resin reinforced with sheets in which strands of carbon filaments are arranged in parallel in unidirection, said sheets being laminated with fiber axes extending orthogonal to one another, or (b) resin reinforced with fabric of strands of carbon filaments.
  • Such conventional antennas have a drawback in that the anisotropy of the paraboloidal front surface with respect to electro-conductivity is so large that the efficiency of transmission and reception varies due to anisotropy of the waves being received.
  • Polarization occurs because carbon filaments which impart electro-conductivity to the paraboloidal front surface and radio-wave-reflectivity to the reflector are arranged with the axes of the filaments extending in two directions, i.e., 0° and 90° directions.
  • a known parabolic antenna includes a reflector having a reflecting layer made of 0.5 mm thick carbon fiber reinforced resin, in which four sheets of carbon filaments are arranged parallel and are laminated. If the directions of the fiber axes of said four sheets are arranged so as to be at, 0°, 90°, 90° and 0° directions, the relationship between the angle 8, which is made by the electric vector of an incident wave (linear polarized wave) against the direction of the axis of carbon filaments constituting the reflecting layer, and the reflection loss R can be expressed by a broken line shown in Figure 4 mentioned later. The relationship indicates that the reflection loss is largely dependent on the direction of arrangement of carbon filaments.
  • the paraboloidal front surface is sometimes laminated with aluminium foil, coated with_ nickel or flame sprayed with zinc.
  • the above-mentioned problem of anisotropy is eliminated because the metal is isotropic with respect to electro-conductivity.
  • this type of antenna lacks durability because the metal is less resistant to the weather and the coating or flame sprayed metal is liable to be damaged.
  • the reflector is made up of two layers, a reflecting surface layer which is about 1 mm thick and a substantially thicker layer of glass fibre reinforced synthetic resin which forms the actual carrier-layer being stiffened by ribs.
  • An exciter is situated at the focal point of the reflector.
  • the reflecting surface layer is made of a mixture of 65% by weight of aluminium grit and 35% by weight of cold-setting synthetic resin.
  • German specification No. 3,106,506 relates to metallized carbon fibres and composite materials containing these fibres.
  • Carbon filament yarn and carbon fibres are provided with a metal coating by means of a currentless process, in order to provide structures having excellent adhesion properties relative to synthetic plastic materials without prejudicing their tensile strength.
  • U.S. Specification No. 3,716,869 relates to a millimeter wave antenna system which is mounted on a satellite. It includes a parabolic reflector made of carbon fibre reinforced plastic composite material to enable the shape of the reflector to be maintained within 3% of 1 mm wavelength despite large temperature fluctuations of the order of 167°C between portions which are illuminated by the sun and those which are in the umbra. A honeycomb structure is sandwiched between layers of carbon fibre reinforced plastic material.
  • U.S. Specification No. 4,388,623 discloses an antenna which has a large area reflector formed of a plurality of conductive slats of carbon fibre reinforced plastics material having air-gaps therebetween. The slats are mounted on a supporting .and shaping framework which is of similar material.
  • porous carbon fibre material with a thin film covering each fibre.
  • Porous material comprises a number of intersecting cut carbon fibres each of which has a diameter of 3-20 pm.
  • the fibres are covered with a thin metal film and are completely and randomly dispersed accumulated and bound with a binder at portions of intersection of the fibres, in order to form a porous structure through which a plurality of pores extend from one surface of the material to the other.
  • U.S. Specification No. 3,137,000 relates to a radio wave reflecting plate wherein skins of plastics reinforced by glass fibres are provided at both surfaces of a paper honeycomb and copper wires are held in parallel spaced relation to each other.
  • a paraboloidal antenna including:
  • the carbon fibres may consist of a mixture of carbon fibers of 5-25 mm in average length with carbon fibers of 1-5 mm in average length.
  • the mixing ratio of the carbon fibers having an average length of 5-25 mm to the carbon fibers having an average length of 1-5 mm may lie in the range of 1:1 to 1:3.
  • the electro conductivity of the above constructed antenna is substantially isotropic. Accordingly, the efficiency of wave transmission and reception does not substantially change in accordance with the direction of wave polarization.
  • the antenna according to the present invention is rated extremely durable.
  • Figure 1 illustrates a parabolic antenna of one embodiment of the present invention.
  • the antenna 1 includes a reflector 2 having a paraboloidal front surface 8 and a primary radiator 3 which is located at the focal point of the paraboloidal front surface 8.
  • a waveguide 4 is provided to guide microwaves or millimeter waves from the primary radiator 3 to subsequent equipment.
  • a framework 5 supports the antenna 1.
  • the reflector 2 includes (a) a reflecting layer 9 having the paraboloidal front surface 8 and made of short carbon fibers/resin composite and (b) a backing layer 10 attached to the rear surface of the reflecting layer 9 and made of short glass fiber reinforced resin.
  • the reflector 2 includes a laminate of the reflecting layer 9 of short carbon fibers/resin composite and the backing layer 10 of short glass fiber reinforced resin.
  • the short carbon fibers/resin composite consists of a thermosetting resin 6 such as epoxy resin, unsaturated polyester resin, phenolic resin, polyimide resin, or a thermoplastic resin 6 such as polyamide resin or polyalkyl resin, and short carbon fibers 7 of 5-25 mm in average length.
  • the short carbon fibers 7 are dispersed in a base layer made of said resin 6 with the axis of each fiber 7 substantially parallel to the paraboloidal front surface 8.
  • short glass fiber reinforced resin short glass fibers 11 of 10-50 cm in average length are used.
  • the short glass fibers 11 are likewise dispersed in a resin with the axis of each fiber substantially parallel to the paraboloidal front surface 8.
  • the short caron fibers 7 in the short carbon fibers/resin composite serve to impart electro-conductivity to the reflecting layer 9.
  • the longer the fibers 7, the better fibers which are too long would result in uneven dispersion, lower conductivity and difficulty in molding. Therefore, the short carbon fibers 7 are desirably 25 mm or less in length. On the other hand, fibers which are too short would improve the moldability but decrease the conductivity.
  • the short carbon fibers 7 are preferably 5-25 mm in average length, more preferably 10-20 mm in average length. From the standpoint of conductivity, the larger the proportion of short carbon fibers 7 contained in the carbon fibers/resin composite, the better. Extremely large proportions of short carbon fibers would, however, decrease the moldability and accordingly, the preferable proportion would be 40-60% by volume based on the total volume of the reflecting layer 9.
  • short carbon fibers of 5-25 mm in average length may be mixed with short carbon fibers of 1-5 mm in average length.
  • the space left by short carbon fibers of 5-25 mm in average length would be filled up with short carbon fibers of 1-5 mm in average length.
  • This mixture would not only reduce the anisotropy in the conductivity but also enhance the conductivity of the paraboloidal front surface 8.
  • relatively short carbon fibers of 1-5 mm in average length would hardly affect the moldability.
  • such a mixture of carbon fibers is desirably such that in terms of weight, the ratio of fibers of 1-5 mm in average length to the fibers of 5-25 mm in average length lies in the range of 1:1 to 3:1.
  • Glass fiber reinforced resin in which short glass fibers are used serves to impart mechanical strength to the antenna.
  • glass fibers 11 of 10-50 cm in average length are adopted.
  • the glass fibers of other structure may be adopted.
  • the glass fibers may be in the form of a mat bonded -with a binder.
  • the preferable weight per unit area of the mat is 3-100 g/m 2 .
  • the sheets of glass filaments 12 which are arranged parallel may be laminated and the directions of the fiber axes of said sheets may be arranged so as to be at about 0°, 90° as shown in Figure 9 or about 0°, 45°, -45°, 90° as shown in Figure 10.
  • use of glass fibers or filaments is not mandatory.
  • Fibers or filaments of alumina, silicon carbide or polyaramide may be used as well as glass fibers or filaments. Further, filaments may be used in the form of a fabric 13 as shown in Figure 11. That is, a glass fiber fabric, an alumina fiber fabric, a silicon carbide fiber fabric and a polyaramide fiber fabric may be used. Instead of fiber reinforced resin, aluminium honeycomb or synthetic paper honeycomb (for example, honeycomb of paper made of poly-m-phenylene isophthalamide) may be employed.
  • the antenna according to the present invention can be manufactured by various methods, one of which is illustrated here.
  • a layer of short carbon fibers bonded with a binder that is a layer of short carbon fiber mat, by a routine process of paper making.
  • the density (a weight per unit area) of the short carbon fiber mat is desirably 30-100 g/m2.
  • an unsaturatated polyester resin film not yet hardened is laid on this short carbon fiber mat and the entire composition is placed in a mold with a paraboloidal surface, to be pressurized and heated for integration, thereby producing a reflector. r.
  • the antenna according to the present invention is available for versatile purposes, for instance, for microwave or millimeter wave communication, broadcasting, radar and TV-broadcast receiving antenna via satellite.
  • the reflection loss was measured as follows.
  • the measuring system was constituted as shown in Figure 3.
  • a high-frequency signal generated by Hewlett Packard's Synthesized Signal Generator HP 8672A (Reference Numeral 12) was transformed into a microwave in the waveguide using a Hewlett Packard's Adapter HP X281 (Reference Numeral 13).
  • the wave propagating through the waveguide and reflected from a sample or a blank copper plate 20 was split by the directional coupler 14 into two parts, one of which went through the isolator 15, impedance- matched by E-H tuner 16, and was transformed into a current signal by the crystal mount 17 and detected by YHP 4041 B pA-meter (pico-ammeter) 18.
  • the isolator and the directional coupler used here were the products of Shimada Rika K.K.
  • the whole measuring system is controlled by a microcomputer "Apple II" 19, while the synthesized signal generator 12 and said pA-meter 18 are coupled by'means of GP-IB.
  • the frequency was swept at every 100 MHz by the synthesized signal generator 12.
  • the measured power of a reflection wave from the blank polished copper plate 20 and, in the second sweeping, the measured power of a reflection wave from the sample, as detected by the pA-meter 18 were memorized and finally the reflected power (dB) of the sample minus the reflected power (dB) of the copper plate at each frequency was yielded as the reflection loss in the sample as an output from the microcomputer.
  • the data at 12 GHz are average values for 16 points taken at 100 MHz interval from 11.5 GHz to 12.5 GHz.
  • the sample and the bland copper plate 20 were measured as inserted between the flanges of the waveguide. As sectionally shown, they were fixed to the flanges by bolts and nuts with holes 21 bored at 4 peripheral points. The rear of the sample was terminated with a nonreflective termination 22 to suppress a subsequent reflection wave.
  • the sample 20 was applied with carbon fibers ("Torayca” manufactured by Toray Industries, Inc.) cut to different lengths with the binder being a polyester resin, by a routine process of paper making.
  • the short carbon fiber mat thus produced was impregnated with epoxy resin #2500, manufactured by Toray Industries, Inc., and heated under pressure to mold it into a board. When the density of the mat is about 50 g/m 2 , the molded product will be about 0.2 mm thick. In the mat, carbon fibers account for 75% by weight with the balance of 25% being the binder.
  • Variation of reflection loss with frequency was compared between a mat A including 50%-3 mm length fibers and 50%-12 mm length fibers and a mat B including 100%-24 mm length fibers, the density being about 50 g/m 2 .
  • Figure 8 shows the results.
  • the reflection loss is desirably more than -0.2 dB.
  • the test results indicate that in the mat B, the values are around -0.2 dB line whereas in the mat A, the values are above this line of -0.2 dB at practically all frequencies. This proves the excellent performance of the mat A as a reflector for the paraboloidal antenna.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Aerials With Secondary Devices (AREA)
  • Reinforced Plastic Materials (AREA)
EP83306201A 1982-10-15 1983-10-13 Antenna Expired EP0109186B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP57179735A JPS5970005A (ja) 1982-10-15 1982-10-15 アンテナ
JP179735/82 1982-10-15

Publications (2)

Publication Number Publication Date
EP0109186A1 EP0109186A1 (en) 1984-05-23
EP0109186B1 true EP0109186B1 (en) 1988-01-07

Family

ID=16070947

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83306201A Expired EP0109186B1 (en) 1982-10-15 1983-10-13 Antenna

Country Status (5)

Country Link
EP (1) EP0109186B1 (ja)
JP (1) JPS5970005A (ja)
KR (1) KR910008947B1 (ja)
CA (1) CA1202414A (ja)
DE (1) DE3375259D1 (ja)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5985003A (ja) * 1982-11-05 1984-05-16 新井　元之助 道路のジョイント
US4647329A (en) * 1984-09-27 1987-03-03 Toyo Kasei Kogyo Kabushiki Kaisha Manufacture of parabolic antennas
FR2597663B1 (fr) * 1986-04-17 1989-02-10 Capron Michel Antenne parabolique et procede pour sa realisation
DE4018452A1 (de) * 1990-06-08 1991-12-19 Buettner Ag Franz Reflektor fuer elektromagnetische wellen und ein beschichtungsmaterial zu dessen herstellung
FR2741200B1 (fr) * 1995-11-15 1998-01-09 Aerazur Coupon destine a la confection d'objets flottants detectables par radar et dispositif a structure gonflable confectionne dans ce coupon
KR100723605B1 (ko) * 2006-02-14 2007-06-04 (주)하이게인안테나 편파 변환형 추적 레이더 안테나
JP4772764B2 (ja) * 2007-09-24 2011-09-14 本田技研工業株式会社 Ｓｏｈｃ型内燃機関の動弁装置
JP7225650B2 (ja) * 2018-10-03 2023-02-21 横浜ゴム株式会社 周波数選択部材およびその製造方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4169911A (en) * 1977-05-10 1979-10-02 Toray Industries, Inc. Porous carbon fiber material with a thin metal film covering each fiber

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB884313A (en) * 1959-08-10 1961-12-13 Gen Electric Co Ltd Improvements in or relating to passive aerials
DE2008266A1 (de) * 1970-02-23 1971-09-09 Inst Rundfunktechnik Gmbh Flachenstrahler mit zweidimensional ge krummter Oberflache fur sehr kurze elektro magnetische Wellen, insbesondere Parabolspie gelantenne
US3716869A (en) * 1970-12-02 1973-02-13 Nasa Millimeter wave antenna system
GB2105913B (en) * 1979-06-28 1983-09-14 Marconi Co Ltd Improvements in or relating to antennas
DE3106506A1 (de) * 1981-02-21 1982-10-07 Bayer Ag, 5090 Leverkusen Metallisierte kohlenstoffasern und verbundwerkstoffe, die diese fasern enthalten
JPS58209202A (ja) * 1982-05-31 1983-12-06 Mitsubishi Chem Ind Ltd 電波反射性成形物およびその製造方法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4169911A (en) * 1977-05-10 1979-10-02 Toray Industries, Inc. Porous carbon fiber material with a thin metal film covering each fiber

Also Published As

Publication number Publication date
DE3375259D1 (en) 1988-02-11
KR910008947B1 (ko) 1991-10-26
CA1202414A (en) 1986-03-25
KR840006576A (ko) 1984-11-30
JPH0380362B2 (ja) 1991-12-24
JPS5970005A (ja) 1984-04-20
EP0109186A1 (en) 1984-05-23

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