Inflatable radome

Patent metadata

Field	Value
Publication number	US-10199723-B2
Application number	US-201214004300-A
Country	US
Kind code	B2
Filing date	Mar 19, 2012
Priority date	Mar 22, 2011
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The invention relates to an inflatable radome containing a flexible radome wall, said radome wall comprising high strength polymeric fibers and further containing a plastomer wherein said plastomer is a semi-crystalline copolymer of ethylene or propylene and one or more C2 to C12 a-olefin co-monomers and wherein said plastomer having a density as measured according to IS01183 of between 860 and 930 kg/m3.

First claim

The invention claimed is:

1. An inflatable radome which is sized and configured to be inflated and deflated repeatedly to cover an electromagnetic antenna, wherein the inflatable radome includes a flexible radome wall, wherein the radome wall includes a fabric comprised of high strength gel spun ultrahigh molecular weight polyethylene (UHMWPE) fibers and a plastomer, wherein
the plastomer is a semi-crystalline copolymer of ethylene or propylene and one or more C2 to C12 α-olefin co-monomers, and wherein
the plastomer has a density as measured according to ISO1183 of between 860 and 930 kg/m 3 , and wherein
the radome wall exhibits reduced electromagnetic radiation losses over a frequency bandwidth range of from 1 GHz to at least 100 GHz and is sufficiently flexible such that an unsupported free end of the radome wall which is separated by 500 mm opposite to a supported end of the radome wall will deflect under its own weight at an angle of more than 10°, and wherein
the radome wall retains shape after repeated inflation and deflation cycles.

2. The inflatable radome of claim 1 , wherein the UHMWPE fibers have a cross-sectional aspect ratio of width to thickness of at least 5:1.

3. The inflatable radome of claim 1 , wherein the UHMWPE fibers have a tensile strength of at least 0.5 GPa.

4. The inflatable radome of claim 1 , wherein the UHMWPE fibers have a tensile modulus of at least 30 GPa.

5. The inflatable radome of claim 1 , wherein the fabric is selected from the group consisting of woven fabrics, knitted fabrics, plaited fabrics, braided fabrics, non-woven fabrics and combinations thereof.

6. The inflatable radome of claim 1 , wherein the fabric is a woven fabric selected from the group consisting of a plain weave fabric and a basket weave fabric.

7. The inflatable radome of claim 1 , wherein the plastomer is impregnated throughout the fabric.

8. The inflatable radome of claim 1 , wherein the plastomer has a tensile modulus of at most 0.6 GPa.

9. The inflatable radome of claim 1 , wherein the fabric is a woven fabric having a cover factor of at least 1.5, wherein the cover factor (CF) is determined by the formula:

CF
=

m
10

⁢

p
⁢

⁢
t

=

m
10

⁢

T

wherein m is the average number of individual weaving yarns per centimeter, p is the number of as produced yarns assembled into a weaving yarn, t is the linear density of the yarn as produced (in tex) and T is the linear density of the individual weaving yarn (in tex).

10. The inflatable radome of claim 1 , wherein the plastomer has a tensile modulus of at least 0.01 GPa.

11. The inflatable radome of claim 1 , wherein the plastomer is present in an amount effective to yield a flexible radome wall having an areal density (AD) that is at least 20% higher than the AD of the fabric.

12. The inflatable radome of claim 1 , wherein the flexible radome wall has a thickness of between 0.2 mm and 10 mm.

13. The inflatable radome of claim 1 , wherein the plastomer is a thermoplastic copolymer of ethylene or propylene containing at least one co-monomer selected from the group consisting of ethylene, isobutene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

14. The inflatable radome of claim 11 , wherein the fabric is a woven fabric, and wherein the plastomer is present in an amount effective to yield a flexible radome wall having an areal density (AD) that is at least 50% higher than the AD of the woven fabric.

Assignees

• Wienke Dietrich
• Van Oosterbosch Eelco
• Dsm Ip Assets Bv

Inventors

• Wienke Dietrich
• Van Oosterbosch Eelco

Classifications

• D06N3/045

  with polyolefin or polystyrene (co-)polymers · CPC title

• H01Q1/427 Primary

  Flexible radomes · CPC title

• D06M2101/20

  Polyalkenes, polymers or copolymers of compounds with alkenyl groups bonded to aromatic groups · CPC title

• H01Q1/42 Primary

  Housings not intimately mechanically associated with radiating elements, e.g. radome · CPC title

• D06N3/0038

  Polyolefin fibres (for elastomeric fibres D06N3/0025) · CPC title