CN115873340A

CN115873340A - Low-dielectric and low-loss antenna housing, and material and method for preparing low-dielectric and low-loss antenna housing

Info

Publication number: CN115873340A
Application number: CN202211212445.7A
Authority: CN
Inventors: D·S·麦克拜恩; N·A·格林
Original assignee: Tianjin Laird Technologies Co Ltd
Current assignee: Tianjin Laird Technologies Co Ltd
Priority date: 2021-09-29
Filing date: 2022-09-29
Publication date: 2023-03-31
Also published as: TWM643952U; TWM651069U; TW202313318A

Abstract

Low dielectric, low loss radomes, materials and methods for making low dielectric, low loss radomes. Exemplary embodiments disclose a low dielectric, low loss radome. Materials and methods for making low dielectric, low loss radomes are also disclosed. In an exemplary embodiment, a material for a low dielectric, low loss radome comprises a foamed thermoplastic having a dielectric constant less than 2.3 at frequencies up to 90GHz and a plurality of closed cells with gas trapped within at least some of the closed cells; or a foamed resin having a plurality of closed cells with gas trapped in at least some of the closed cells, the foamed resin comprising polypropylene and/or a polyolefin; or microspheres within a resin matrix, wherein the resin matrix comprises a cyclic olefin copolymer.

Description

Low-dielectric and low-loss antenna housing, and material and method for preparing low-dielectric and low-loss antenna housing

Technical Field

The present disclosure relates generally to low dielectric, low loss radomes, materials and methods for making low dielectric, low loss radomes.

Background

This section provides background information related to the present disclosure that is not necessarily prior art.

A radome is an electromagnetically transparent environmentally friendly enclosure for an antenna. Radome designs must generally meet the structural requirements of the outdoor environment and minimize electromagnetic energy losses.

Disclosure of Invention

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

Exemplary embodiments disclose low dielectric, low loss radomes. Materials and methods for making low dielectric, low loss radomes are also disclosed.

Paragraph 1. A material for a low dielectric, low loss radome, the material comprising:

a foamed thermoplastic having a dielectric constant of less than 2.3 at frequencies up to 90GHz and a plurality of closed cells with gas entrapped within at least some of the closed cells; or

A foamed resin having a plurality of closed cells with gas entrapped within at least some of the closed cells, the foamed resin comprising polypropylene and/or polyolefin; or alternatively

Microspheres within a resin matrix, wherein the resin matrix comprises a cyclic olefin copolymer.

Paragraph 2. The material of paragraph 1, wherein the material comprises:

the foamed thermoplastic comprises nitrogen or carbon dioxide entrapped within at least some of the closed cells of the foamed thermoplastic; or alternatively

The foamed resin includes nitrogen or carbon dioxide entrapped within at least some of the closed cells of the foamed resin.

Paragraph 3. The material of paragraph 1, wherein the material comprises:

the foamed thermoplastic, with the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a weight reduction in the range of about 10% to about 25% of the foamed thermoplastic; or alternatively

The foamed resin, with the gas entrapped within at least some of the closed cells of the foamed resin, provides a weight reduction in the range of about 10% to about 25% of the foamed resin.

Paragraph 4. The material of paragraph 1, wherein the material comprises:

the foamed thermoplastic, with the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a weight reduction in the foamed thermoplastic in the range of from about 15% to about 20%; or alternatively

The foamed resin, with the gas entrapped within at least some of the closed cells of the foamed resin, provides a weight reduction in the range of about 15% to about 20% of the foamed resin.

Paragraph 5 the material of paragraph 1, wherein the material comprises:

the foamed thermoplastic, with the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a reduction in dielectric constant of at least about 10%; or alternatively

The foamed resin, having the gas trapped within at least some of the closed cells of the foamed resin, provides a dielectric constant reduction of at least about 10%.

Paragraph 6. The material of paragraph 1, wherein the material comprises:

the foamed thermoplastic having a lower dielectric constant due to the gas entrapped within at least some of the closed cells of the foamed thermoplastic, the foamed thermoplastic having a cell density in a range of about 20% to about 50%, and the foamed thermoplastic having a closed cell content; or

The foamed resin having a lower dielectric constant due to the gas entrapped within at least some of the closed cells of the foamed resin, the foamed resin having a cell density in a range of about 20% to about 50%, and the foamed resin having a closed cell content.

Paragraph 7. The material of paragraph 1, wherein the material comprises:

said foamed thermoplastic comprising a microcellular polymeric foam; or

The foam resin comprising a microcellular polymeric foam.

Paragraph 8. The material of paragraph 1, wherein the material comprises:

said foamed thermoplastic comprising a polyolefin; or alternatively

The foamed resin comprising a polyolefin.

Paragraph 9. The material of paragraph 8, wherein the polyolefin comprises a cyclic olefin copolymer.

Paragraph 10. The material of paragraph 1, wherein:

the material comprises the foamed thermoplastic, the foamed thermoplastic comprising a blend of polypropylene and a cyclic olefin copolymer; or

The material includes the foamed resin, which includes a blend of polypropylene and a cyclic olefin copolymer.

Paragraph 11. The material of paragraph 10, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises at least about 5 wt% to about 50 wt% of the cyclic olefin copolymer.

Paragraph 12. The material of paragraph 11, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises about 80 wt.% of the polypropylene and about 20 wt.% of the cyclic olefin copolymer.

Paragraph 13. The material of paragraph 10, wherein the blend of the polypropylene and the cyclic olefin copolymer has an average dielectric constant of about 2.2 for frequencies from 18GHz to 40 GHz; and wherein:

the material comprises the foamed thermoplastic and the gas trapped within at least some of the closed cells of the foamed thermoplastic reduces the dielectric constant such that the foamed thermoplastic has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz; or

The material includes the foamed resin and the gas trapped within at least some of the closed cells of the foamed resin reduces a dielectric constant such that the foamed resin has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz.

Paragraph 14. The material of paragraph 1, wherein:

the material comprises the foamed thermoplastic comprising one or more open cells in addition to the plurality of closed cells having the gas entrapped within at least some of the closed cells of the foamed thermoplastic; or

The material comprises the foamed resin, the foamed resin comprising one or more open cells in addition to the plurality of closed cells having the gas entrapped within at least some of the closed cells of the foamed resin.

Paragraph 15. The material of paragraph 1, wherein:

the material comprises the microspheres within the resin matrix; and is

The microspheres comprise hollow glass, plastic and/or ceramic microspheres, microbeads or bubbles within the resin matrix.

Paragraph 16. The material of paragraph 15, wherein the microspheres comprise glass microspheres within the resin matrix.

Paragraph 17. The material of paragraph 16, wherein the material comprises about 50% by volume of the glass microspheres.

Paragraph 18. The material of paragraph 15, wherein the material comprises:

about 40% to about 60% by volume of the resin matrix; and

about 40% to about 60% by volume of said microspheres.

Paragraph 19. The material of paragraph 1, wherein:

the material comprises the microspheres within the resin matrix;

the resin matrix comprises a blend of polypropylene and the cyclic olefin copolymer; and is

The microspheres are within the blend of the polypropylene and the cyclic olefin copolymer.

Paragraph 20. The material of paragraph 19, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises at least about 5 wt.% to about 50 wt.% of the cyclic olefin copolymer.

Paragraph 21. The material of paragraph 20, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises about 80 wt.% of the polypropylene and about 20 wt.% of the cyclic olefin copolymer.

Paragraph 22. The material of paragraph 19, wherein:

the microspheres comprise glass microspheres within the blend of the polypropylene and the cyclic olefin copolymer such that the material comprises about 50 volume percent of the glass microspheres; and is

The material has a dielectric constant less than 2.1 for frequencies from 18GHz to 40 GHz.

Paragraph 23. The material of any of paragraphs 1 to 22, wherein the material comprises fibers comprising polytetrafluoroethylene within the material.

Paragraph 24. The material of paragraph 23, wherein the material comprises from about 0.1% to about 5% by weight of the fibers comprising polytetrafluoroethylene.

Paragraph 25. The material of paragraph 24, wherein the material comprises from about 0.2% to about 3% by weight of the fibers comprising polytetrafluoroethylene.

Paragraph 26. The material of paragraph 25, wherein the material comprises from about 0.3% to about 2% by weight of the fibers comprising polytetrafluoroethylene.

Paragraph 27. The material of paragraph 1, wherein the material includes one or more impact modifiers within the material.

Paragraph 28. The material of paragraph 27, wherein the one or more impact modifiers within the material comprise one or more of acrylic styrene acrylonitrile, methacrylate butadiene styrene terpolymer, acrylate polymethacrylate copolymer, chlorinated polyethylene, ethylene vinyl acetate copolymer, acrylonitrile butadiene styrene terpolymer, and/or polyacrylate.

Paragraph 29. The material of paragraph 1, wherein the material has a dielectric constant of less than 2.1 at frequencies up to 90 GHz.

Paragraph 30. The material of paragraph 1, further comprising a flame retardant within the material, whereby the material has a UL94 flame retardant rating of V0.

Paragraph 31. The material of any one of paragraphs 1 to 22 and 27 to 30, wherein:

the material complies with ROHS instructions 2011/65/EU and (EU) 2015/863; and/or

The material complies with REACH as it contains less than 0.1 wt% material on the REACH/SVHC candidate list (6 months and 25 days 2020).

Paragraph 32. The material of any of paragraphs 1 to 22 and 27 to 30, wherein the material comprises cadmium not exceeding 0.01 wt% regulatory threshold, lead not exceeding 0.1 wt% regulatory threshold, mercury not exceeding 0.1 wt% regulatory threshold, hexavalent chromium not exceeding 0.1 wt% regulatory threshold, the flame retardant PBB not exceeding 0.1 wt% regulatory threshold, and PBDE comprising pentabromodiphenyl ether (CAS-No. 32534-81-9), octabromodiphenyl ether (CAS-No. 32536-52-0) and decabromodiphenyl ether (CAS-No. 1163-19-5)), di (2-ethylhexyl) phthalate (DEHP) (CAS-No. 117-81-7) not exceeding 0.1 wt% regulatory threshold, butylbenzoate (BBP) (CAS-No. 85-68-7) not exceeding 0.1 wt% regulatory threshold, dimethyl phthalate (CAS-84-74) not exceeding 0.1 wt% regulatory threshold (CAS-84-5) and dibutyl phthalate (CAS-No. 84-5-wt% regulatory threshold).

Paragraph 33. The material of paragraph 1, wherein the material is configured to have:

a dielectric constant less than 1.9 for frequencies up to 90 GHz; and

a loss tangent of less than 0.01 for frequencies up to 90 GHz.

Paragraph 34. The material of paragraph 1, wherein the material is injection moldable.

Paragraph 35. The material of paragraph 1, wherein the material comprises thermoplastic injection moldable pellets.

Paragraph 36. A radome made from the material of paragraph 1, wherein the material comprises the microspheres integrated into the resin matrix such that:

the radome is not provided with an outer skin and an inner skin defining a three-layer sandwich a structure on opposite sides of the core; and/or

The radome has a homogeneous and/or unitary structure that is thermoformable prior to curing and/or has a substantially uniform low dielectric constant of less than 2.1 throughout the thickness of the radome.

Paragraph 37 a radome, at least a portion of which is made of a material according to any one of paragraphs 1 to 22, 27 to 30 and 33 to 35.

Paragraph 38. The radome of paragraph 37, wherein the radome is injection molded from the material.

Paragraph 39. The radome of paragraph 37, wherein:

the radome has a dielectric constant of less than 2.1 for frequencies up to 90 GHz;

the radome has a loss tangent less than 0.01 at frequencies up to 90 GHz; and is

The radome has a UL94 flame retardant rating of V0.

Paragraph 40 the radome of paragraph 37, wherein the radome is configured for use with a millimeter wave 5G antenna, a 5G repeater, and/or a 5G-to-WiFi 6 router.

Paragraph 41. An apparatus comprising the radome of paragraph 37.

Paragraph 42. The apparatus of paragraph 41, wherein the apparatus is a millimeter wave 5G antenna, a 5G repeater, and/or a 5G to WiFi6 router.

Paragraph 43. A method of making a low dielectric, low loss radome, the method comprising injection molding the material according to paragraph 1, thereby providing at least a portion of the radome that is injection molded from the material.

Paragraph 44. A method of making a low dielectric, low loss radome, the method comprising the steps of:

injecting a fluid into the thermoplastic to provide a foamed thermoplastic having a dielectric constant of less than 2.3 at frequencies up to 90 GHz; and

injection molding the foamed thermoplastic to provide at least a portion of the radome that is injection molded from the foamed thermoplastic.

Paragraph 45. The method of paragraph 44, wherein the fluid comprises nitrogen or carbon dioxide.

Paragraph 46. The method of paragraph 44, wherein the step of injecting a fluid comprises injecting a supercritical fluid into the thermoplastic.

Paragraph 47. The method of paragraph 46, wherein the injected supercritical fluid is converted to a gas phase and gas is trapped within at least some of the closed cells of the foamed thermoplastic.

Paragraph 48. The method of paragraph 47, wherein the gas entrapped within at least some of the closed cells of the foamed thermoplastic provides a weight reduction in the range of about 10% to about 25%.

Paragraph 49. The method of paragraph 47, wherein the gas trapped within at least some of the closed cells of the foamed thermoplastic provides a weight reduction in the range of about 15% to about 20%.

Paragraph 50. The method of paragraph 47, wherein the gas trapped within at least some of the closed cells of the foamed thermoplastic provides a reduction in dielectric constant of at least about 10%.

Paragraph 51. The method of paragraph 47, wherein the gas trapped within at least some of the closed cells of the foamed thermoplastic reduces the dielectric constant such that the foamed thermoplastic has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz.

Paragraph 52. The method of paragraph 44, wherein the method includes a microcellular foam injection molding process in which the fluid is injected into the thermoplastic and the foamed thermoplastic is injection molded.

Paragraph 53. The method according to paragraph 44, wherein the step of injecting a fluid comprises: injecting a supercritical fluid into the thermoplastic, the supercritical fluid comprising carbon dioxide or nitrogen as a physical blowing agent, whereby the foamed thermoplastic comprises a thermoplastic having a size in the range of 1 to 100 microns and a cell density greater than 10 ⁹ Pores per cm ³ The microcellular polymer foam of microcellular gas bubbles.

Paragraph 54. The method of paragraph 44, wherein the method does not include the use of a chemical blowing agent such that the foamed thermoplastic is free of any chemical residue from the chemical blowing agent within the foamed thermoplastic.

Paragraph 55. The method of paragraph 44, wherein the foamed thermoplastic comprises a polyolefin.

Paragraph 56. The method of paragraph 55, wherein the polyolefin comprises a cyclic olefin copolymer.

Paragraph 57 the method of paragraph 44, wherein the foamed thermoplastic comprises polypropylene.

Paragraph 58. The method of any of paragraphs 44 to 54, wherein the foamed thermoplastic comprises a blend of polypropylene and cyclic olefin copolymer.

Paragraph 59. The method of paragraph 58, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises at least about 5 wt.% to about 50 wt.% of the cyclic olefin copolymer.

Paragraph 60. The method of paragraph 59, wherein the blend of the polypropylene and the cyclic olefin copolymer comprises about 80 wt% of the polypropylene and about 20 wt% of the cyclic olefin copolymer.

Paragraph 61. The method of paragraph 58, wherein the blend of the polypropylene and the cyclic olefin copolymer has an average dielectric constant of about 2.2 for frequencies from 18GHz to 40 GHz.

Paragraph 62. The method of any of paragraphs 44 to 54, wherein the foamed thermoplastic comprises fibers comprising polytetrafluoroethylene within the foamed thermoplastic.

Paragraph 63. The method of paragraph 62, wherein the foamed thermoplastic comprises about 0.1 wt.% to about 5 wt.% of the fibers comprising polytetrafluoroethylene.

Paragraph 64. The method of paragraph 63, wherein the foamed thermoplastic comprises about 0.2 wt.% to about 3 wt.% of the fibers comprising polytetrafluoroethylene.

Paragraph 65. The method of paragraph 64, wherein the foamed thermoplastic comprises about 0.3 wt.% to about 2 wt.% of the fibers comprising polytetrafluoroethylene.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Fig. 1 is a plot of dielectric constant versus frequency (gigahertz (GHz)) for injection molded thermoplastics and injection molded foamed thermoplastics with microspheres for radomes in accordance with exemplary embodiments of the present disclosure. As shown in fig. 1, the injection molded foamed thermoplastic has a dielectric constant of less than 2.25 for the frequency range from 18GHz to 40 GHz.

FIG. 2 is a line graph of dielectric constant versus frequency (gigahertz (GHz)) for an injection molded foamed polyolefin thermoplastic according to an exemplary embodiment of the present disclosure. As shown in FIG. 2, the injection molded foamed polyolefin thermoplastic has a dielectric constant of less than 2 for the frequency range from 18GHz to 40 GHz.

Fig. 3 illustrates a sample of a material including glass microspheres in a resin blend of polypropylene and a cyclic olefin copolymer, which may be used for a radome, according to an exemplary embodiment of the present disclosure.

Fig. 4 illustrates a sample of a material including a foam resin blend of polypropylene and a cyclic olefin copolymer, which may be used for a radome, according to an exemplary embodiment of the present disclosure.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings.

Conventional radomes are made of composite materials that can meet the structural requirements for outdoor use. As recognized herein, however, conventional radome composites tend to have relatively high dielectric constants (e.g., dielectric constants of 2.8 or higher, etc.) and dielectric loss tangents, particularly at high frequencies.

Accordingly, disclosed herein are exemplary embodiments of materials for a low dielectric, low loss radome configured to have an overall low dielectric constant and an overall low loss tangent or dissipation factor (Df) at relatively high frequencies. For example, exemplary embodiments of radomes made from the materials disclosed herein are configured to have an overall low dielectric constant and an overall low loss tangent or dissipation factor (Df) at millimeter wave frequencies and/or relatively high frequencies (e.g., from about 20 gigahertz (GHz) to 90GHz, from about 20GHz to about 50GHz, from about 18GHz to about 40GHz, etc.).

In exemplary embodiments, radomes made from the materials disclosed herein can be configured to have a dielectric constant of about 2.1 or less at frequencies from about 20GHz to about 90GHz and/or from about 20GHz to about 50GHz and/or from about 18GHz to about 40 GHz. For example, the radome can be configured to have an average dielectric constant of about 1.93 or less (e.g., about 1.923 or less, about 1.906 or less, etc.) at frequencies from about 18GHz to about 40 GHz. Alternatively, for example, the radome can be configured to have an average dielectric constant of about 2.083 or less at frequencies from about 18GHz to about 40 GHz.

In an exemplary embodiment, the material for the low dielectric, low loss radome comprises a foamed thermoplastic. The foamed thermoplastic has a dielectric constant of less than 2.3 at frequencies up to 90 GHz. The foamed thermoplastic has a plurality of closed cells with gas trapped in at least some of the closed cells. The foamed thermoplastic may include one or more open cells in addition to closed cells that trap gas within at least some of the closed cells.

In exemplary embodiments, the gas trapped within at least some (e.g., all, less than all, most, etc.) of the closed cells of the foamed thermoplastic comprises nitrogen or carbon dioxide. The entrapped gas within at least some of the closed cells of the foamed thermoplastic provides a weight reduction in the range of from about 10% to about 25% because the density of the gas is less than the density of the unfoamed thermoplastic. For example, entrapped gas within at least some of the closed cells of the foamed thermoplastic may provide a weight reduction in the range of about 15% to about 20%. In addition, the entrapped gas within at least some of the closed cells of the foamed thermoplastic provides a reduction in dielectric constant of at least about 10% because the dielectric constant of the gas is lower than the dielectric constant of the unfoamed thermoplastic.

In an exemplary embodiment, the foamed thermoplastic has a lower dielectric constant due to gas trapped within at least some of the closed cells. The foamed thermoplastic has a cell density in the range of about 20% to about 50%. The foamed thermoplastic has a closed cell content.

In exemplary embodiments, the foamed thermoplastic includes polyolefins such as polypropylene, cyclic olefin copolymers, polyethylene (e.g., low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), ultra High Density Polyethylene (UHDPE), etc.), other polymers in the polyolefin family, and combinations or blends thereof (e.g., blends of polypropylene and cyclic olefin copolymers, etc.), and the like.

In an exemplary embodiment, the foamed thermoplastic comprises a blend of polypropylene and polyolefin. The blend of polypropylene and cyclic olefin copolymer may have an average dielectric constant of about 2.2 for frequencies from 18GHz to 40 GHz. The entrapped gas within at least some of the closed cells may reduce the dielectric constant such that the foamed thermoplastic has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz. The blend of polypropylene and cyclic olefin copolymer can include at least about 5 wt% to about 50 wt% cyclic olefin copolymer (e.g., 5 wt%, 20 wt%, 50 wt%, etc.). For example, the blend of polypropylene and cyclic olefin copolymer may include about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer.

In an exemplary embodiment, the material for the low dielectric, low loss radome comprises a foam resin. The foamed resin includes polypropylene and/or polyolefin. The foamed resin has a plurality of closed cells with gas trapped within at least some (e.g., all, less than all, a majority, etc.) of the closed cells. The foamed resin may include one or more open cells in addition to a plurality of closed cells having gas trapped within at least some of the closed cells.

In an exemplary embodiment, the gas trapped within at least some of the closed cells of the foamed resin comprises nitrogen or carbon dioxide. The entrapped gas within at least some of the closed cells of the foamed resin provides a weight reduction in the range of about 10% to about 25% because the density of the gas is less than the density of the unfoamed resin. For example, entrapped gas within at least some of the closed cells of the foamed resin may provide a weight reduction in the range of about 15% to about 20%. In addition, the entrapped gas within at least some of the closed cells of the foamed resin provides a reduction in dielectric constant of at least about 10% because the dielectric constant of the gas is lower than the dielectric constant of the unfoamed resin.

In an exemplary embodiment, the foamed resin includes a polyolefin including a cyclic olefin copolymer. For example, the foamed resin may include a blend of polypropylene and a cyclic olefin copolymer. The blend of polypropylene and cyclic olefin copolymer may have an average dielectric constant of about 2.2 for frequencies from 18GHz to 40 GHz. The entrapped gas within at least some of the closed cells reduces the dielectric constant such that the foamed resin has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz. The blend of polypropylene and cyclic olefin copolymer can include at least about 5 wt% to about 50 wt% cyclic olefin copolymer (e.g., 5 wt%, 20 wt%, 50 wt%, etc.). For example, the blend of polypropylene and cyclic olefin copolymer may include about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer.

In an exemplary embodiment, the foam resin has a lower dielectric constant due to gas trapped within at least some of the closed cells. The foamed resin has a cell density in the range of about 20% to about 50%. The foamed resin has a closed cell fraction.

In an exemplary embodiment, a material for a low dielectric, low loss radome comprises microspheres within a resin matrix. The resin matrix includes a cyclic olefin copolymer.

In an exemplary embodiment, the resin matrix comprises a blend of polypropylene and a cyclic olefin copolymer. And the microspheres are in a blend of polypropylene and cyclic olefin copolymer.

In an exemplary embodiment, the microspheres comprise glass microspheres within a blend of polypropylene and cyclic olefin copolymer such that the material comprises about 50% by volume of the glass microspheres. For frequencies from 18GHz to 40GHz, the material has a dielectric constant of less than 2.1. The blend of polypropylene and cyclic olefin copolymer can include at least about 5 wt% to about 50 wt% cyclic olefin copolymer (e.g., 5 wt%, 20 wt%, 50 wt%, etc.). For example, the blend of polypropylene and cyclic olefin copolymer may include about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer.

In exemplary embodiments, the microspheres comprise hollow glass, plastic and/or ceramic microspheres, microbeads or bubbles within a resin matrix. For example, the microspheres may include glass microspheres within a resin matrix such that the material includes about 50% by volume of the glass microspheres.

In an exemplary embodiment, the material includes from about 40% to about 60% by volume of the resin matrix (e.g., about 50% by volume of the resin matrix, etc.) and from about 40% to about 60% by volume of the microspheres (e.g., about 50% by volume of the microspheres, etc.).

In an exemplary embodiment, the radome is made of a material comprising microspheres within a resin matrix comprising a cyclic olefin copolymer. The microspheres are integrated into the resin matrix such that: the radome is free of outer and inner skin layers (defining a three-layer a sandwich structure) disposed on opposite sides of the core; and/or the radome has a homogeneous and/or unitary structure that is thermoformable prior to curing and/or has a substantially uniform low dielectric constant of less than 2.1 throughout the thickness of the radome.

Exemplary methods of making low dielectric, low loss radomes are also disclosed herein. An exemplary method comprises: injecting a fluid into the thermoplastic to provide a foamed thermoplastic having a dielectric constant of less than 2.3 at frequencies up to 90 GHz; and injection molding the foamed thermoplastic to provide at least a portion of the radome injection molded from the foamed thermoplastic.

In an exemplary method, the step of injecting a fluid into the thermoplastic comprises injecting a supercritical fluid into the thermoplastic. The injected supercritical fluid is converted to a gas phase, trapping the gas within at least some (e.g., all, less than all, most, etc.) of the closed cells of the foamed thermoplastic. For example, the method may include a plasticizing process in which supercritical carbon dioxide or nitrogen gas is injected into the thermoplastic. The injected supercritical fluid is mixed and/or dispensed (e.g., homogenously, etc.) into the thermoplastic, thereby creating a single-phase injection moldable solution comprised of the supercritical fluid and the thermoplastic. The injection moldable solution can then be introduced or injected into the mold cavity of the radome. And the filling of the mould cavity can be carried out at a relatively low pressure. Within the mold cavity, the cells (cells) will begin to nucleate upon exposure to the lower pressure within the mold cavity, and the molecular dispersion of the supercritical fluid will provide a homogeneous closed cell structure with a solid skin. After the mold cavity is filled, the controlled cell growth can provide a relatively uniform and locally applied dwell pressure throughout the mold cavity.

In an exemplary method, the fluid comprises nitrogen or carbon dioxide. Thermoplastics include polyolefins such as polypropylene, cyclic olefin copolymers, polyethylene (e.g., low Density Polyethylene (LDPE), high Density Polyethylene (HDPE), ultra High Density Polyethylene (UHDPE), etc.), other polymers in the polyolefin family, as well as combinations or blends thereof (e.g., blends of polypropylene and cyclic olefin copolymers, etc.), and the like.

In an exemplary method, the entrapped gas within at least some of the closed cells of the foamed thermoplastic provides a weight reduction in the range of from about 10% to about 25% because the density of the gas is less than the density of the unfoamed thermoplastic. For example, entrapped gas within at least some of the closed cells of the foamed thermoplastic may provide a weight reduction in the range of about 15% to about 20%. In addition, the entrapped gas within at least some of the closed cells of the foamed thermoplastic provides a reduction in dielectric constant of at least about 10% because the dielectric constant of the gas is lower than the dielectric constant of the unfoamed thermoplastic. The entrapped gas within at least some of the closed cells of the foamed thermoplastic reduces the dielectric constant such that the foamed thermoplastic has an average dielectric constant of less than 2 for frequencies from 18GHz to 40 GHz.

In an exemplary method, the thermoplastic comprises a blend of polypropylene and a cyclic olefin copolymer. The blend of polypropylene and cyclic olefin copolymer can include at least about 5 wt% to about 50 wt% cyclic olefin copolymer (e.g., 5 wt%, 20 wt%, 50 wt%, etc.). For example, a blend of polypropylene and cyclic olefin copolymer includes about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer. In addition, the blend of polypropylene and cyclic olefin copolymer has an average dielectric constant of about 2.2 for frequencies from 18GHz to 40 GHz.

In an exemplary method, the foamed thermoplastic includes fibers within the foamed thermoplastic that include Polytetrafluoroethylene (PTFE). In these exemplary embodiments, the foamed thermoplastic may include about 0.1 wt.% to about 5 wt.% PTFE fibers. For example, the foamed thermoplastic may include about 0.2 wt% to about 3 wt% PTFE fibers. Preferably, the foamed thermoplastic includes about 0.3 wt.% to about 2 wt.% PTFE fibers.

An exemplary method includes a microcellular foam injection molding process in which a supercritical fluid is injected into a thermoplastic and a foamed thermoplastic is injection molded. In these exemplary methods, the supercritical fluid may include carbon dioxide or nitrogen gas as a physical blowing agent. The foamed thermoplastic can include, for example, microcellular bubbles having a size from 1 micron to 100 microns (e.g., a size less than 50 microns, etc.) and a size greater than 10 ⁹ Pores/cm ³ Cell density, etc.

In an exemplary method, no chemical blowing agent is used, such that the foamed thermoplastic is free of any chemical residue from the chemical blowing agent within the foamed thermoplastic.

In an exemplary method, the foamed thermoplastic comprises a blend of polypropylene and a cyclic olefin copolymer. The blend of polypropylene and cyclic olefin copolymer can include at least about 5 wt% to about 50 wt% cyclic olefin copolymer (e.g., 5 wt%, 20 wt%, 50 wt%, etc.). For example, the blend of polypropylene and cyclic olefin copolymer may include about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer.

In an exemplary embodiment, the material includes one or more impact modifiers within the material. The one or more impact modifiers within the material may include one or more of acrylic styrene acrylonitrile, methacrylate butadiene styrene terpolymers, acrylate polymethacrylate copolymers, chlorinated polyethylene, ethylene vinyl acetate copolymers, acrylonitrile butadiene styrene terpolymers, and/or polyacrylates.

In an exemplary embodiment, the material includes fibers (e.g., aramid, polytetrafluoroethylene (PTFE), etc.) within the material. For example, the fibers may include one or more of a fire resistant meta-aramid material, polytetrafluoroethylene (PTFE), other suitable fibrous materials, combinations thereof, and the like. In an exemplary embodiment, the material may include a fibrillated Cyclic Olefin Copolymer (COC).

In an exemplary embodiment, the material includes fibers within the material, wherein the fibers include Polytetrafluoroethylene (PTFE). In these exemplary embodiments, the material may include about 0.1% to about 5% by weight PTFE fibers. For example, the material may include about 0.2 wt% to about 3 wt% PTFE fibers. Preferably, the material comprises about 0.3 wt% to about 2 wt% PTFE fibers.

In an exemplary embodiment, the material further includes a flame retardant within the material.

In an exemplary embodiment, the material has a dielectric constant of less than 2.1 at frequencies up to 90 GHz. And the material has a UL94 flame rating of V0.

In an exemplary embodiment, the material complies with ROHS instructions 2011/65/EU and (EU) 2015/863; and/or the material complies with REACH as comprising less than 0.1% by weight of material on the REACH/SVHC candidate list (6 months and 25 days 2020).

In an exemplary embodiment, the material includes cadmium not exceeding 0.01 wt% regulatory threshold, lead not exceeding 0.1 wt% regulatory threshold, mercury not exceeding 0.1 wt% regulatory threshold, hexavalent chromium not exceeding 0.1 wt% regulatory threshold, flame retardants PBB and PBDE not exceeding 0.1 wt% regulatory threshold (including pentabromodiphenyl ether (CAS-No. 32534-81-9), octabromodiphenyl ether (CAS-No. 32536-52-0), and decabromodiphenyl ether (CAS-No. 1163-19-5)), di (2-ethylhexyl) phthalate (DEHP) (CAS-No. 117-81-7) not exceeding 0.1 wt% regulatory threshold, butylbenzyl phthalate (BBP) (CAS-No. 85-68-7) not exceeding 0.1 wt% regulatory threshold, dibutyl phthalate (DBP) (CAS-No. 84-74-2) not exceeding 0.1 wt% regulatory threshold, and di bp (CAS-No. 69-84-5) not exceeding 0.1 wt% regulatory threshold.

In an exemplary embodiment, the material is configured to have: a dielectric constant less than 1.9 for frequencies up to 90 GHz; and a loss tangent of less than 0.01 for frequencies up to 90 GHz.

In an exemplary embodiment, the material is injection moldable.

In an exemplary embodiment, the material comprises thermoplastic injection moldable pellets.

In an exemplary embodiment, at least a portion of the radome is made of a material disclosed herein. For example, the entire radome may be injection molded from the material. For frequencies up to 90GHz, the radome may have a dielectric constant of less than 2.1. At frequencies up to 90GHz, the radome may have a loss tangent of less than 0.01. The radome can have a UL94 flame retardant rating of V0. The radome may be configured for use with a millimeter wave 5G antenna, a 5G repeater, and/or a 5G-to-WiFi 6 router.

In an exemplary embodiment, an apparatus includes a radome, at least a portion of which is made of a material disclosed herein. The apparatus may be a millimeter wave 5G antenna, a 5G repeater, and/or a 5G to WiFi6 router.

In an exemplary embodiment, a method of making a low dielectric, low loss radome, the method comprises: the material disclosed herein is injection molded, thereby providing at least a portion of the radome that is injection molded from the material.

For illustrative purposes only, data will now be provided for different material samples according to exemplary embodiments. For the first series of tests, a sample of material (fig. 3) included glass microspheres within a resin blend of polypropylene (PP) and Cyclic Olefin Copolymer (COC). A sample of material comprised about 50 volume percent glass microspheres and about 50 volume percent PP/COC blend. The PP/COC blend comprises about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer. The material sample had a thickness of about 2.04 millimeters.

For frequencies from 18GHz to 40GHz, testing of material samples revealed an SPDR (split column dielectric resonator) average dielectric constant of 2.059 and average dielectric constants of 2.083, 2.078, 2.023, and 2.022. Further with respect to SPDR, table 1 below provides additional information regarding dielectric constant and tangent loss.

TABLE 1

			mm
							HZ	Q	Thickness of	dK	Tangent loss
Air (a)	1201.78	15465	-
						1	1198.94	11964	2.04	2.055	2.07E-03
2	1198.94	12053	2.04	2.057	2.00E-03
						3	1198.93	11897	2.04	2.059	2.11E-03
4	1198.93	11999	2.04	2.060	2.04E-03
						5	1198.95	11936	2.04	2.054	2.09E-03
6	1198.92	11985	2.04	2.062	2.04E-03
						7	1198.93	11908	2.04	2.059	2.11E-03
8	1198.93	12037	2.04	2.060	2.01E-03
						9	1198.93	12028	2.04	2.058	2.02E-03
10	1198.91	11854	2.04	2.068	2.14E-03

For the second series of tests, a sample of material (fig. 4) was made via a microcellular foam injection molding process in which a carbon or nitrogen supercritical fluid was injected into a resin blend of polypropylene (PP) and Cyclic Olefin Copolymer (COC), thereby providing a microcellular foam comprising a PP/COC blend. The PP/COC blend comprises about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer. The microcellular foam samples had a thickness of about 1.91 millimeters.

Testing of the microcellular foam samples revealed an SPDR average dielectric constant of 1.98 and an average dielectric constant of 1.9143 for frequencies from 18GHz to 40 GHz. By comparison, the unfoamed PP/COC blend has a higher SPDR average dielectric constant of 2.27 and a higher average dielectric constant of 2.22 for frequencies from 18GHz to 40 GHz. Further with respect to the SPDR, table 2 below provides additional information regarding the dielectric constant and tangent loss of the microcellular foam samples.

TABLE 2

Table 3 provides additional information on (1) polypropylene (PP), (2) Cyclic Olefin Copolymer (COC), (3) PP/COC blends comprising about 80 wt% polypropylene and about 20 wt% cyclic olefin copolymer, and (4) PP/COC blends having about 50 vol% glass microspheres within the PP/COC blend. For dielectric constant, loss tangent, and ball drop impact testing, a relatively flat sheet of a material test sample (e.g., fig. 3) was evaluated. For the additional physical data provided in table 3 below, the sample material was injection molded into a standardized stretch rod and a standardized bend rod.

TABLE 3

In general, testing has shown that PP/COC blends with glass microspheres have lower dielectric constants, lower insertion losses, and lower weight than PP/COC blends alone. And the PP/COC blend with glass microspheres has sufficient flexibility and strength. Tests also show that the foamed PP/COC resin blend has a lower dielectric constant, lower insertion loss and lower weight compared to PP/COC blends with glass microspheres. And the foamed P/COC resin blend has sufficient flexibility and strength.

By way of example, tables 1, 2, and 3 above include exemplary properties that antenna cover materials (e.g., microcellular polymeric foams, foamed PP/COC resin blends, foamed thermoplastics, PP/COC blends including microspheres, etc.) may have in exemplary embodiments. In other exemplary embodiments, the materials used for the radome and radomes made therefrom can be configured differently, e.g., having one or more of the different properties shown in tables 1, 2 and 3 above, etc.

In an exemplary embodiment, the radome may be configured to have a low dielectric constant, low loss, and low weight. The radome may be configured or adapted for outdoor applications with strong impact resistance, structural requirements for high tensile strength, and rigidity. The radome has an ultra-low dielectric constant outer surface to enhance antenna signal performance and provide better impact resistance. The low dielectric constant outer incident surface allows for less loss of signal strength as a signal enters the material as compared to an overall low dielectric constant (dK) material having a higher dielectric constant outer surface. Radomes can be used to provide environmental protection of the antenna with very low signal interference. The radome may be configured (e.g., optimized, etc.) for performance in 5G antenna applications. The radome can have a low dielectric surface that increases radome performance with increased signal pass-through strength. Radomes can be an environmentally friendly solution to RoHS and REACH. The radome can be thermoplastic and can be thermoformed into complex curves to suit device applications and aesthetic requirements. The radome can be painted to meet customer desired color requirements. The radome may be configured for use with 5G indoor antennas, routers (e.g., 5G to WiFi6 routers, etc.), repeaters (e.g., indoor 5G repeaters, etc.), and the like. The radome may be configured for use as an in-building wireless radome, a 5G small cell indoor radome, or the like.

In an exemplary embodiment, the radome may comprise a homogeneous dielectric constant material that provides a uniform dielectric constant across its width. This allows a low dielectric constant at the initial incident surface for increased signal pass-through strength and better signal performance at off angles. The homogeneous structure of the radome increases radome performance at higher angles of incidence with increased signal pass-through strength and better signal performance.

In exemplary embodiments, the material for the radome may be made by a method or process (e.g., calendering, etc.) in which the fibers/fabric are embedded, integrated, incorporated, combined and/or mixed within a resin matrix comprising Cyclic Olefin Copolymer (COC) with microspheres (e.g., hollow glass microspheres, hollow plastic microspheres, hollow ceramic microspheres, microbeads or bubbles, etc.). The embedded fibers/fabric may provide reinforcement and strength to the material for carrying loads, while the low dielectric microspheres preferably help to reduce the overall dielectric constant. The embedded fibers/fabrics may include NOMEX fire resistant meta-aramid materials, DACRON loosely woven polymer fabrics, other prepregs or reinforcement materials, and the like. The radome material may be stretched or otherwise three-dimensionally shaped. In these exemplary embodiments, the radome has a single structure, e.g., no 3-layer laminate a sandwich structure, no separate outer and inner skin layers, etc.

In exemplary embodiments, the radome configuration is anisotropic and/or configured to provide performance enhancement by minimizing or reducing cross-polarization differences between horizontal and vertical polarizations. The radome may be configured to direct, focus, reflect, or diffuse overlapping signals or beams having different polarizations for less divergence. The radome may be configured to be anisotropic by: the fibers are embedded when the microspheres are calendered or mixed so that the fibers have a predetermined orientation (e.g., vertically oriented and/or horizontally oriented, etc.). By orienting the fibers in a predetermined orientation, the radome can be configured to be anisotropic and have different properties in different directions.

In an exemplary embodiment, a thinner flame retardant coating or layer may be applied to and/or integrated into at least a portion of the radome, such that the radome has a UL94 burn rating. The flame retardant coating or layer may be sufficiently thin (e.g., in a range from about 0.002 microns to about 0.005 microns in thickness) so as not to completely block or obstruct the open cells of the core material of the radome. In further exemplary embodiments, the radome is not resin sealed in order to also maintain the open honeycomb or porous structure of the radome. By maintaining an open cell or porous structure of the radome, a lower dielectric constant of the radome can be maintained. The flame retardant may include a phosphorus-based flame retardant that is halogen-free (e.g., ammonium phosphate salts, etc.). By way of example, the flame retardant may include no more than 900 parts per million chlorine maximum, no more than 900 parts per million bromine maximum, and no more than 1500 parts per million total halogen.

The exemplary embodiments disclosed herein may include or provide one or more (but not necessarily any or all) of the following advantages or features, such as:

overall low dielectric constant and overall low loss tangent or dissipation factor (Df) at millimeter wave frequencies and/or higher frequencies; and/or

A relatively strong core structure (e.g., a polyolefin with microspheres (e.g., hollow glass microspheres, hollow plastic microspheres, hollow ceramic microspheres, microbeads or bubbles, etc.) that minimizes or at least reduces electromagnetic energy loss, etc.); and/or

An outer portion (e.g., outer surface, skin, etc.) that provides environmental protection and is capable of withstanding high impact; and/or

Lower cost; and/or

Allowing the use of compression molding processes to manufacture complex shaped radomes; and/or

Flame retardancy (e.g., UL94 flammability certification, etc.); and/or

Suitable for outdoor use (e.g., UL756C F1 Ultraviolet (UV) and water immersion certification, etc.); and/or

Suitable for long-term environmental heat (e.g., UL 746B RTI certification, etc.).

In an exemplary embodiment, the radome may be configured to provide outdoor environmental protection to the 5G/millimeter wave antenna. In an exemplary embodiment, the radome may be configured for use with indoor antennas, repeaters (e.g., indoor 5G repeaters, etc.), routers (e.g., 5G to WiFi6 indoor routers, etc.), devices that convert 5G signals to WiFi for use within a building (e.g., commercial building facilities), and the like. In exemplary embodiments, the radome may be configured for use as an in-building wireless radome, a 5G small cell indoor radome, or the like.

Example embodiments disclosed herein may include or provide one or more (but not necessarily any or all) of the following use benefits, such as very low signal loss for high frequencies, ultra-low dielectric constant materials, rigidity, impact resistance, good tensile strength for structural requirements, and/or light weight. Exemplary embodiments may accommodate millimeter wave 5G frequencies (e.g., 28GHz, 39GHz, etc.) and/or frequencies of about 20GHz to about 90GHz and/or about 20GHz to about 50GHz and/or about 18GHz to about 40 GHz. Exemplary embodiments of the low dielectric constant radomes disclosed herein can allow for boosting power at 5G frequencies (e.g., by about 25% or more, etc.) as 5G signals tend to have problems penetrating into buildings and homes, as compared to some conventional radomes where power boosting may be advantageous.

The example embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that none should be construed to limit the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Additionally, the advantages and improvements that may be realized with one or more exemplary embodiments of the present invention are provided for purposes of illustration only and do not limit the scope of the present disclosure (as the exemplary embodiments disclosed herein may provide none, all, or one of the above-described advantages and improvements, and still fall within the scope of the present disclosure).

Specific dimensions, specific materials, and/or specific shapes disclosed herein are exemplary in nature and do not limit the scope of the disclosure. The disclosure herein of specific values and specific value ranges for a given parameter is not exhaustive of the other values and value ranges that may be used in one or more of the examples disclosed herein. Moreover, it is contemplated that any two particular values for a particular parameter recited herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter may be interpreted as disclosing that any value between the first and second values may also be employed for the given parameter). For example, if parameter X is illustrated herein as having a value a and is also illustrated as having a value Z, it is contemplated that parameter X may have a range of values from about a to about Z. Similarly, it is contemplated that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping, or distinct) encompasses all possible combinations of ranges of values for which endpoints of the disclosed ranges can be clamped. For example, if parameter X is exemplified herein as having a value in the range of 1-10 or 2-9 or 3-8, it is also contemplated that parameter X may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises" and "comprising" are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

When an element or layer is referred to as being "on," "engaged with," "connected to," or "coupled to" another element or layer, it can be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged with," "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in the same fashion (e.g., "between 8230; \8230; between pairs" directly between 8230; \8230; between "," adjacent "pairs" directly adjacent ", etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The term "about" when applied to a value indicates that the calculation or measurement allows the value to be slightly imprecise (near exact in value; approximately or reasonably close in value; nearly). If, for some reason, the imprecision provided by "about" is not otherwise understood in the art with this ordinary meaning, then "about" as used herein indicates at least variations that may result from ordinary methods of measuring or using such parameters. For example, the terms "generally," "about," and "approximately" may be used herein to mean within manufacturing tolerances.

Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Spatially relative terms (such as "inner," "outer," "below," "lower," "above," "upper," and the like) may be used herein for convenience in describing the relationship of one element or feature to another element or feature as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The foregoing description of the embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, contemplated or stated uses or features of a particular embodiment are generally not limited to that particular embodiment, but, where appropriate, are interchangeable and can be used in a selected embodiment (even if the embodiment is not specifically shown or described). The same content may also be changed in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A material for a low dielectric, low loss radome, the material comprising:

A foamed resin having a plurality of closed cells with gas entrapped within at least some of the closed cells, the foamed resin comprising polypropylene and/or polyolefin; or

2. The material of claim 1, wherein the material comprises:

the foamed thermoplastic comprises nitrogen or carbon dioxide entrapped within at least some of the closed cells of the foamed thermoplastic; or

3. The material of claim 1, wherein the material comprises:

the foamed thermoplastic, with the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a weight reduction in the range of about 10% to about 25% of the foamed thermoplastic; or

The foamed resin, having the gas entrapped within at least some of the closed cells of the foamed resin, provides a weight reduction in the range of about 10% to about 25% of the foamed resin.

4. The material of claim 1, wherein the material comprises:

the foamed thermoplastic, having the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a weight reduction in the foamed thermoplastic in the range of from about 15% to about 20%; or

5. The material of claim 1, wherein the material comprises:

the foamed thermoplastic, with the gas entrapped within at least some of the closed cells of the foamed thermoplastic, providing a reduction in dielectric constant of at least about 10%; or

The foamed resin, with the gas entrapped within at least some of the closed cells of the foamed resin, provides a reduction in dielectric constant of at least about 10%.

6. The material of claim 1, wherein the material comprises:

7. The material of claim 1, wherein the material comprises:

said foamed thermoplastic comprising a microcellular polymeric foam; or

The foam resin comprising a microcellular polymeric foam.

8. The material of claim 1, wherein the material comprises:

said foamed thermoplastic comprising a polyolefin; or

The foamed resin including a polyolefin.

9. The material of claim 8, wherein the polyolefin comprises a cyclic olefin copolymer.

10. The material of claim 1, wherein: