GB2207814A - Electromagnetically-transparent radome - Google Patents
Electromagnetically-transparent radome Download PDFInfo
- Publication number
- GB2207814A GB2207814A GB08815837A GB8815837A GB2207814A GB 2207814 A GB2207814 A GB 2207814A GB 08815837 A GB08815837 A GB 08815837A GB 8815837 A GB8815837 A GB 8815837A GB 2207814 A GB2207814 A GB 2207814A
- Authority
- GB
- United Kingdom
- Prior art keywords
- ptfe
- structure according
- layer
- copolymer
- membrane
- 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.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/02—Arrangements for de-icing; Arrangements for drying-out ; Arrangements for cooling; Arrangements for preventing corrosion
-
- 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
- H01Q1/422—Housings not intimately mechanically associated with radiating elements, e.g. radome comprising two or more layers of dielectric material
Landscapes
- Laminated Bodies (AREA)
- Details Of Aerials (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
Abstract
An electromagnetically-transparent structure, which is weather-, moisture-, and gas-resistant, for enclosing and protecting a radio antenna including a layer of laminate, comprising adhered layers of polytetrafluoroethylene (PTFE) membrane (2), thermoplastic polymer (3), a second layer of PTFE membrane (2), and a backing fabric (4) comprising woven fibres of PTFE.
Description
ELECTROMAGNETICALLY-TRANSPARENT STRUCTURE The present invention relates to
a structure for covering and protecting a radio antenna such as a radar antenna, against weather and moisture, while remaining electromagnetically transparent.
Large radio antennas, such as radar installations and radio telescopes, often need a covering structure of some kind to protect them from the weather, i.e. sunlight, wind, and moisture and which will preferably be gas-tight; this covering structure is referred to as a radome. One type of radome is an inflatable radome. In this case, a gas-tight balloon shrouds the antenna. A blower inflates the balloon and spaces the structure away from the antenna so that the antenna may move or rotate freely. A popular form of such covering is the geodesic dome or metal space frame radome, which is formed from many metal (or other structural material) geometric shaped segments, such as triangles and others, which are covered with an appropriate radio frequency transmitting membrane, then affixed to each other to form a part-spherical dome surrounding the radar antenna, which rotates or moves inside the radome. Positive gas pressure is not required inside the metal space frame radome, but may be useful at 2 times. for example, to dislodge snow from the outside of the dome, or to aid in controlling the environment within the dome. Another type of installation has solid segmented covering doors over the radio antenna which open to allow the antenna to function through the opening.
On each side of the opening is affixed a semicircular track, up which is drawn each edge of a large, nearly electromagnetically transparent sheet of protective membrane to cover the antenna while in use. Other forms of antennas can also be suitably covered by 'such membranes held above or affixed around them in various ways to keep out moisture and the effects of weather, While useful in varying degrees, the various forms and compositions of membrane hitherto known in the art, such as polytetrafluoroethylene fibre- glass laminates, have not solved all of the problems associated with use of this type of covering for protecting radio antennas.
According to the present invention there is provided an electromagnetically-transparent structure, which is weather, moisture. and gas-resistant, for enclosing and protecting a radio antenna including a layer of laminate, comprising adhered layers of w v 3 polytetrafluoroethylene (PM) membrane, thermoplastic polymer, a second layer of PTFE membrane, and a backing fabric, comprising woven fibres of PTFE. The preferred membranes and fibres are of porous PTFE and preferably of porous expanded PTFE (EPTFE) prepared as described in U.S. Patents 3,953,566; 4,096,227; 4187,390; 4,110,392; 4,025,679; 3,962,153, and 4,482,516.
The invention will now be particularly described, by way of example, with reference to the accompanying drawings in which:- Figure 1 is a cross-section of a preferred laminate according to the invention; Figure 2 is a broken-away view of a space frame radome covering and protecting h rotating radio antenna, and Figure 3 shows a radio telescope housing, where shutter and doors are drawn aside and a covering sheet of composite membrane is being drawn over the antenna.
Figure 1 illustrates a laminate 1 according to the invention in crosssection showing various layers. The outer layer 2 is of polytetrafluoroethylene (PM), preferably porous PTFE, and most preferably EPTFE.
4 EPTFE is the porous expanded PTFE membrane material made by stretching PTFE in the manner described in the U.S. patents listed above. EPTFE has superior dielectric constant and loss tangent characteristics thus aiding electromagnetic transmission. The outer layer 2 is bonded by means of a thermoplastic polymer layer 3 to a second layer 2 of EPTFE which has previously been adhered or bonded to a textile backing layer 4 comprising woven fibres of PM. Here again, the preferred form of PTFE is EPTFE.
Layer 3 of thermoplastic polymer is preferably a fluorinated ethylenepropylene co-polymer (FEP), but other fluorinated thermoplastic polymers might be used where their PTFE-adhesive properties, radar wavelength transparency, and gas-resistant properties are suitable for use in the particular laminate being prepared. other non-fluorinated thermoplastic polymers may be used for layer 3 where they meet the criteria of sufficient adhesiveness, electromagnetic transmission characteristics, and gas-proofness or gas-resistance to be adequately functional and useful. Useful thermoplastic polymers may include perfluoroalkoxytetrafluoroethylene polymers, ethylenetetrafluorofluoroethylene copolymers, copolymers of vinylidene fluoride and hexafluoropropylene, polychlorotrifluoroethylene, copolymer of hexafluoropropylene and tetrafluoroethylene, polyethylene and polypropylene. Layer 4 is a woven textile backing fabric for the laminate where the fibres are PTFE, preferably porous PTFE, and most preferably E. PM. Layer 4 provides strength properties to the laminate, and additional layers of this material may be added where an increase in laminate strength is needed and desired.
The woven PTFE or EPTFE fabric is coated with commercially available PTFE dispersion or thermoplastic polymer dispersion to about three to ten percent by weight dispersed PTFE add-on and laminated to an EPTFE film under hot pinch-roll conditions under pressure. Another EPTFE membrane is adhered to FEP film under heat and pressure. The FEP side of this second laminate is then laminated to the EPTFE side of the first laminate by hot pressure rolling to form a four-layer laminate, such as that depicted in cross-section in Figure 1. Additional pairs of layers 2 and 3 may be laminated to the EPTFE f ace of the laminate in like manner. if desired, to change the electromagnetic transmission characteristics or gas resistance.
1 6 Some variation among the fluorinated thermoplastics available for layer 3 may be utilized as well to adjust the electromagnetic transmission characteristics and frequency demand. The laminate provides significant gas-resistance or gas-proof properties associated with the thermopolastic layer (or layers) so as to be useful for positive pressure type structures in which gas pressure within the dome or shelter holds the covering away from the rotating or moving parts of the antenna housed therein.
Figure 2 shows a large metal space frame radome for sheltering and enclosing a radio antenna 5. Thesegments 6 of the dome have been made by covering geometric shaped frames, usually of metal or other stiff construction materials such as metal or plastic tubing or shaped bar stock, with laminate of this invention. Segements 6 are then assembled into a radome as shown. Other methods for making such a frame, not involving geometric segments, can be made to serve as well and other methods for covering the domes with the laminate 1 of the invention may be used.
Figure 3 depicts a different type of housing or shelter for a radio antenna 9, in which the entire housing revolves, a roof shutter 7 and doors 8 roll out of the S 7 way of antenna 9, and a large sheltering sheet 11 of composite membrane of the invention is drawn up track 10 to which it is attached at each end to protect the antenna while it is in use. Sheet 11 of Figure 3 and the covering 6 of each segment of the geodesic dome of Figure 2 each embody one form of the present invention.
The laminates are inert to and unaffected by the elements, including sunlight. ozone, temperature extremes, wind. rain, and snow, and are inert, hydrophobic and gas-resistant. They are very thin and strong, have excellent colour reflectance and electromagnetic transmission. low dielectric constant, and low loss tanget. The laminates when used in radomes reduce maintenance costs, provide lower cost structural enclosures, allow more accurate measurements, and provide for increased viewing time, do not need to be painted or otherwise maintained as do other materials., and have low adhesion and excellent release for snow and ice which might form on the surface of the radome.
8
Claims (7)
1 1. An electromagnetically-transparent structure, which is weather, moisture. and gas-resistant, for enclosing and protecting a radio antenna including a layer of laminate, comprising adhered layers of polytetrafluoroethylene (PM) membrane, thermoplastic polymer, a second layer of PTFE membrane. and a backing fabric comprising woven fibres of PTFE.
iz
2. A structure according to claim 1, wherein the first and second layers of PTFE are porous
3. A structure according to claim 2, wherein the first and second layers of PTFE are porous expanded PTFE (EPTFE).
4. A structure according to claim 3, wherein the backing fabric is EPTFE.
5. A structure according to claim 4, wherein the thermoplastic polymer is a fluorinated ethylene- propylene co-polymer (FEP).
6. A structure according to claim 5, wherein the thermoplastic polymer is perfluoroalkoxy- P 9 tetrafluoroethylene tetrafluoroethylene vinylidene fluoride (FPA) an ethylene copolymer. a copolymer of and chlorotrifluoroethylene, a copolymer of vinylidene fluoride and hexafluoro propylene, polychlorotrifluoroethylene, a copolymer of hexafluoropropylene and tetrafluoroethylene, poly ethylene, or polypropylene.
7. A structure substantially as, and for the purpose, herein described with reference to the accompanying drawing.
Published 1988 at The Patent Office, State House, 66 71 High Holborn. London WC1R 4TP Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orplngtori. Kent BR5 3RD. Printed bY Multiplex techniques ltd. St Mary Cray, Kent. Con 1 87
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US8374687A | 1987-08-06 | 1987-08-06 |
Publications (2)
Publication Number | Publication Date |
---|---|
GB8815837D0 GB8815837D0 (en) | 1988-08-10 |
GB2207814A true GB2207814A (en) | 1989-02-08 |
Family
ID=22180425
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08815837A Withdrawn GB2207814A (en) | 1987-08-06 | 1988-07-04 | Electromagnetically-transparent radome |
Country Status (16)
Country | Link |
---|---|
EP (1) | EP0302596B1 (en) |
JP (2) | JP2642958B2 (en) |
KR (1) | KR890004466A (en) |
CN (1) | CN1015414B (en) |
AT (1) | ATE86411T1 (en) |
AU (1) | AU603900B2 (en) |
CA (1) | CA1310573C (en) |
DE (1) | DE3878777T2 (en) |
DK (1) | DK438988A (en) |
ES (1) | ES2038293T3 (en) |
FI (1) | FI90928C (en) |
GB (1) | GB2207814A (en) |
IE (1) | IE62504B1 (en) |
IS (1) | IS1500B (en) |
NO (1) | NO173962C (en) |
PT (1) | PT88153A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2250804A (en) * | 1990-11-07 | 1992-06-17 | Colebrand Ltd | Protective device |
WO1998016967A1 (en) * | 1996-09-13 | 1998-04-23 | W.L. Gore & Associates, Inc. | Satellite dish cover |
US6208314B1 (en) * | 1996-09-04 | 2001-03-27 | Tele-Equipement | Satellite reception antenna |
JP2017531099A (en) * | 2014-09-16 | 2017-10-19 | ディーエスエム アイピー アセッツ ビー.ブイ. | Space frame radome with polymer sheet |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5217797A (en) * | 1992-02-19 | 1993-06-08 | W. L. Gore & Associates, Inc. | Chemically resistant diaphragm |
WO1994001899A1 (en) * | 1992-07-02 | 1994-01-20 | W. L. Gore & Associates, Inc. | Sealing frame and protective membrane for a radar dish or horn |
US5904978A (en) * | 1995-12-15 | 1999-05-18 | W. L. Gore & Associates, Inc. | Electrically conductive polytetrafluoroethylene article |
EP0786823A1 (en) * | 1996-01-22 | 1997-07-30 | W.L. GORE & ASSOCIATES, INC. | Non-woven electro-magnetically transparent material |
US5947918A (en) * | 1996-11-18 | 1999-09-07 | Gore Enterprise Holdings, Inc. | Impact energy absorbing composite materials |
US5945217A (en) * | 1997-10-14 | 1999-08-31 | Gore Enterprise Holdings, Inc. | Thermally conductive polytrafluoroethylene article |
US6770577B2 (en) * | 2001-10-29 | 2004-08-03 | Gore Enterprise Holdings, Inc. | Architectural fabric |
NL1026919C2 (en) * | 2004-08-27 | 2006-02-28 | Nedap Agri B V | Ultra-wide-band system for determining animals. |
WO2009099965A2 (en) | 2008-02-05 | 2009-08-13 | Saint-Gobain Performance Plastics Corporation | Multi-layer article |
CN101364669B (en) * | 2008-09-25 | 2012-08-29 | 东华大学 | Polyethylene reinforced radar cowl of ultra-high molecular weight, preparation and application thereof |
US8859102B2 (en) | 2008-11-12 | 2014-10-14 | Saint-Gobain Performance Plastics Corporation | Barrier structure and method for making |
CN102264542A (en) * | 2008-11-12 | 2011-11-30 | 美国圣戈班性能塑料公司 | Barrier structure and method for making thereof |
TWI397620B (en) * | 2010-06-30 | 2013-06-01 | Method for Making Tensile Teflon (ePTFE) Line | |
CN109462003A (en) * | 2018-10-11 | 2019-03-12 | 江苏三和欣创通信科技有限公司 | A kind of measurement antenna system based on full frequency band |
CN110808465B (en) * | 2019-09-27 | 2021-02-02 | 浙江瑞堂塑料科技股份有限公司 | High-wave-transmittance radome and preparation process thereof |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA962021A (en) * | 1970-05-21 | 1975-02-04 | Robert W. Gore | Porous products and process therefor |
US4025679A (en) * | 1976-08-06 | 1977-05-24 | W. L. Gore & Associates, Inc. | Fibrillated polytetrafluoroethylene woven filter fabric |
JPS56110304A (en) * | 1980-02-05 | 1981-09-01 | Mitsubishi Electric Corp | Film material for radome |
JPS5925808U (en) * | 1982-08-04 | 1984-02-17 | 三菱樹脂株式会社 | Cover for parabolic antenna |
JPS6082813U (en) * | 1983-11-14 | 1985-06-08 | 日東電工株式会社 | Antenna reflector cover structure |
DE3410501C2 (en) * | 1984-03-22 | 1990-09-13 | Dornier System Gmbh, 7990 Friedrichshafen | Radome material |
DE3410503A1 (en) * | 1984-03-22 | 1986-01-02 | Dornier System Gmbh, 7990 Friedrichshafen | METHOD FOR PRODUCING RADOMAS |
US4615933A (en) * | 1984-04-06 | 1986-10-07 | Rogers Corporation | Radome structure and method of manufacture thereof |
DE3421196A1 (en) * | 1984-06-07 | 1985-12-19 | Dornier System Gmbh, 7990 Friedrichshafen | Radome material |
JPS6286714U (en) * | 1985-11-20 | 1987-06-03 |
-
1988
- 1988-06-08 AU AU17508/88A patent/AU603900B2/en not_active Ceased
- 1988-07-04 GB GB08815837A patent/GB2207814A/en not_active Withdrawn
- 1988-07-04 EP EP88306093A patent/EP0302596B1/en not_active Expired - Lifetime
- 1988-07-04 AT AT88306093T patent/ATE86411T1/en not_active IP Right Cessation
- 1988-07-04 ES ES198888306093T patent/ES2038293T3/en not_active Expired - Lifetime
- 1988-07-04 DE DE8888306093T patent/DE3878777T2/en not_active Expired - Fee Related
- 1988-07-29 FI FI883578A patent/FI90928C/en not_active IP Right Cessation
- 1988-07-29 PT PT88153A patent/PT88153A/en not_active Application Discontinuation
- 1988-08-01 JP JP63190730A patent/JP2642958B2/en not_active Expired - Fee Related
- 1988-08-02 NO NO883421A patent/NO173962C/en unknown
- 1988-08-03 IE IE236788A patent/IE62504B1/en not_active IP Right Cessation
- 1988-08-04 IS IS3379A patent/IS1500B/en unknown
- 1988-08-05 DK DK438988A patent/DK438988A/en not_active Application Discontinuation
- 1988-08-05 CA CA000573921A patent/CA1310573C/en not_active Expired - Fee Related
- 1988-08-06 KR KR1019880010068A patent/KR890004466A/en not_active Application Discontinuation
- 1988-08-06 CN CN88104934A patent/CN1015414B/en not_active Expired
-
1995
- 1995-09-26 JP JP7247849A patent/JP2662381B2/en not_active Expired - Fee Related
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2250804A (en) * | 1990-11-07 | 1992-06-17 | Colebrand Ltd | Protective device |
US5187321A (en) * | 1990-11-07 | 1993-02-16 | Colebrand Limited | Protective device |
GB2250804B (en) * | 1990-11-07 | 1994-06-01 | Colebrand Ltd | Protective device for a sensing head |
US6208314B1 (en) * | 1996-09-04 | 2001-03-27 | Tele-Equipement | Satellite reception antenna |
WO1998016967A1 (en) * | 1996-09-13 | 1998-04-23 | W.L. Gore & Associates, Inc. | Satellite dish cover |
JP2017531099A (en) * | 2014-09-16 | 2017-10-19 | ディーエスエム アイピー アセッツ ビー.ブイ. | Space frame radome with polymer sheet |
Also Published As
Publication number | Publication date |
---|---|
FI90928C (en) | 1994-04-11 |
EP0302596A1 (en) | 1989-02-08 |
FI90928B (en) | 1993-12-31 |
AU603900B2 (en) | 1990-11-29 |
KR890004466A (en) | 1989-04-22 |
IE62504B1 (en) | 1995-02-08 |
ATE86411T1 (en) | 1993-03-15 |
IS3379A7 (en) | 1989-02-07 |
JPH08181522A (en) | 1996-07-12 |
CN1031050A (en) | 1989-02-15 |
CA1310573C (en) | 1992-11-24 |
FI883578A (en) | 1989-02-07 |
JPH01114101A (en) | 1989-05-02 |
CN1015414B (en) | 1992-02-05 |
IE882367L (en) | 1989-02-06 |
IS1500B (en) | 1992-07-30 |
GB8815837D0 (en) | 1988-08-10 |
DE3878777T2 (en) | 1993-06-09 |
EP0302596B1 (en) | 1993-03-03 |
PT88153A (en) | 1989-06-30 |
NO883421L (en) | 1989-02-07 |
DE3878777D1 (en) | 1993-04-08 |
DK438988D0 (en) | 1988-08-05 |
NO173962B (en) | 1993-11-15 |
JP2642958B2 (en) | 1997-08-20 |
JP2662381B2 (en) | 1997-10-08 |
NO173962C (en) | 1994-02-23 |
ES2038293T3 (en) | 1993-07-16 |
DK438988A (en) | 1989-02-07 |
NO883421D0 (en) | 1988-08-02 |
AU1750888A (en) | 1989-02-09 |
FI883578A0 (en) | 1988-07-29 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |