TW201413002A - Microsphere-filled-metal components for wireless-communication towers - Google Patents

Abstract

A wireless-communications-tower component being at least partially formed from a microsphere-filled metal. The microsphere-filled metal has a density of less than 2.7 g/cm<SP>3</SP>, a thermal conductivity greater than 1 W/m.K, and a coefficient of thermal expansion of less than 30 μ m/m.K. Microspheres suitable for use in such microsphere-filled metal include, for example, glass microspheres, mullite microspheres, alumina microspheres, alumino-silicate microspheres, ceramic microspheres, silica-carbon microspheres, carbon microspheres, and mixtures of two or more thereof.

Description

Microsphere filled metal component for wireless communication tower Reference to relevant application

The present invention claims priority to U.S. Provisional Application No. 61/707,085, filed on Sep. 28, 2012.

field

Various embodiments of the present invention are directed to metal-based components for wireless communication towers.

Preface

In the field of communication systems, it is expected that global bandwidth demand will increase year by year to support new services and increase the number of users, thus shifting wireless systems to higher frequency bandwidth. There is a trend in the industry to move base station electronics from the tower base to a higher area of the wireless communication tower (ie, the tower top electronics); this is to reduce the signal loss of the communication cable connecting the tower top to the bottom unit. . As the number of components moved to the top of the tower increases, the weight of such components becomes a problem.

summary

An embodiment is an apparatus comprising: a wireless communication tower assembly formed at least in part by a metal filled with microspheres, wherein the microsphere filled metal is measured at 25 ° C, having less than 2.7 per cubic centimeter The density of grams ("g/cm ³ ").

Detailed description

Various embodiments of the present invention are directed to a wireless communication tower assembly formed at least in part from a metal-based material. Such metal-based materials may have certain properties that make them suitable for use in overhead applications, including certain ranges of density, thermal conductivity, and coefficient of thermal expansion. Such wireless communication tower assemblies may include radio frequency ("RF") cavity filters, heat sinks, housings, tower top support assemblies, combinations thereof, and the like.

Metal-based material

As just mentioned, the wireless communication tower assembly can be formed at least in part from a metal based material. As used herein, a "metal-based" material is a material that comprises a metal as a major (i.e., greater than 25 weight percent ("wt%")) component. In various embodiments, the metal-based material can comprise one or more metals combined in a total amount of at least 50, at least 60, at least 70, at least 80, at least 90, or at least 95 wt%. In some embodiments, one or more metals constitute all or substantially all of the metal-based material. As used herein, the term "substantially all" refers to the presence of less than 10 parts per million ("ppm") of the undescribed component alone. Another In other embodiments, the metal-based material can be a composite of a metal and one or more fillers, as described in more detail below, and thus can be included in a lower ratio of one or more metals (eg, from As low as 5 wt% up to 99 wt%).

The metal component of the metal-based material can be any metal or combination of metals (i.e., alloys) known or later discovered. In various embodiments, the metal-based juice material may comprise a low density metal such as aluminum or magnesium, or an alloy of other metals such as nickel, iron, bronze, copper or the like. In one or more embodiments, the metal-based material may comprise a metal alloy such as aluminum or magnesium and alloys thereof. In certain embodiments, the metal-based material comprises aluminum. In various embodiments, the aluminum constitutes at least 50, at least 60, at least 70, at least 80, at least 90, at least 95 wt%, substantially all or all of the metal component of the metal-based material. Therefore, in various embodiments, the metal-based material may be an aluminum-based material. In addition, the aluminum used may be an aluminum alloy such as AA 6061. Alloy 6061 typically comprises 97.9 wt% aluminum, 0.6 wt% rhodium, 0.28 wt% copper, 1.0 wt% magnesium, and 0.2 wt% chromium.

As noted above, the metal based material can have certain characteristics. In various embodiments, the metal-based material has less than 2.7, less than 2.6, less than 2.5, less than 2.4, less than 2.3, less than 2.2, less than 2.1, or less than 2.0 grams per cubic centimeter. The density of ("g/cm ³ "). In such embodiments, the metal-based material can have a density of at least 0.1 g/cm ³ . Since the metal-based material may comprise a polymer-metal composite, the density values provided herein may be measured at 25 ° C according to ASTM D792, as described below. For non-polymer/metal composite materials, the density can be measured by density gradient method according to ASTM D1505.

In various embodiments, the metal-based material has a thermal conductivity of Kelvin temperature greater than 1, greater than 2, greater than 3, greater than 4, greater than 5, or greater than 6 watts ("W/m.K") per meter. Sex. In these embodiments, the metal-based material may have no more than 50, or no more than 100, no more than 180, or no more than 250 W/m. The thermal conductivity of K. All of the thermal conductivity values provided herein are measured at 25 ° C according to ISO 22007-2 (Instantaneous Planar Heat Source [Hot Disc] Method). In various embodiments, the metal-based material has a Kjeldahl temperature of less than 50, less than 45, less than 40, less than 35, less than 30, or less than 26 microns per meter ("μm/m.K," which is equal to ppm /°C) Linear isotropic thermal expansion coefficient ("CTE"). In these embodiments, the metal-based material may have a size of at least 10 μm/m. K's CTE. All CTE values provided herein are measured by the procedures provided in the Test Methods section below.

In various embodiments, the metal based material has a tensile strength of at least 5.0 megapascals ("MPa"). In such embodiments, the metal-based material can have an ultimate tensile strength of typically no greater than 500 MPa. Since the metal-based materials referred to herein are also related to polymer-metal composites, all tensile strengths provided herein are measured in accordance with ASTM D638. For samples of only metals, the tensile properties were measured according to ASTM B557M.

In various embodiments, the metal-based material can be a foamed metal. As used herein, the term "foamed metal" means a metal having a porous structure having a volumetric portion of a voided void. The hair The metal of the metal foam can be any metal suitable for the preparation of foamed metal known or later discovered in the art. For example, the metal of the foamed metal may be selected from the group consisting of aluminum, magnesium, copper, and the like, and the like. In certain embodiments, the foamed metal can be expanded aluminum.

In various embodiments, the foamed metal can have a density ranging from 0.1 to 2.0 g/cm ³ , from 0.1 to 1.0 g/cm ³ , or from 0.25 to 0.5 g/cm ³ . In some embodiments, the foamed metal may have a relative density from 0.03 to 0.9, from 0.1 to 0.7, or from 0.14 to 0.5, wherein the relative density (no scale) is defined as the density of the foamed metal. The ratio of the density of the base metal (ie, non-foamed samples of other identical metals). In addition, the foamed metal may have from 5 to 150 W/m. K, from 8 to 125W/m. K, or from 15 to 80 W/m. Thermal conductivity in the K range. Furthermore, the foamed metal may have a thickness of from 15 to 25 μm/m. K, or from 19 to 23 μm/m. CTE within the K range. In various embodiments, the foamed metal may have a tensile strength in the range of from 5 to 500 MPa, from 20 to 400 MPa, from 50 to 300 MPa, from 60 to 200 MPa, or from 80 to 200 MPa.

In various embodiments, the foamed metal can be a closed-cell foamed metal. As is known in the art, the term "closed" means a structure in which the major portion of the voided void in the metal-based material is an isolated void (i.e., not joined to other voided voids). The closed foamed metal can generally have a cell size ranging from 1 to 8 millimeters ("mm").

In various embodiments, the foamed metal can be an open-cell foamed metal. As known in the art, the term "open" is used. A structure is shown in which a major portion of the voids in the metal-based material is interconnected (i.e., in open contact with one or more adjacent holes). The open foamed metal can generally have a cell size ranging from 0.5 to 10 mm.

Commercially available foamed metal can be used in the various embodiments described herein. For example, suitable expanded aluminum materials are available from Isotech Inc., whether in sheet or 3 dimensional molds. Such materials may also be self Foamtech ^TM Corporation, Racemat ^TM BV, is obtained and Reade ^TM International, are all sheet-like.

In various embodiments, particularly when an open foamed metal is used, the foamed metal may have a surface region or a portion of the surface region that is (a) a non-foamed metal or (b) a polymer The main material is coated. In such embodiments, the foamed metal may thus be present on a surface that is free or substantially free of defects (i.e., smooth). Such surfaces may facilitate metal plating and allow for the formation of components that require a smooth surface, such as the formation of heat sinks, where the desired strength may not be achieved by the foamed structure alone. In addition, because of the waiting degree, the fins are not usually added with a large amount of weight in the construction, so it is desirable to retain a non-foamed structure or to fill the void hole of the foamed structure with a polymer-based material to increase the strength. . When a surface area is non-foamed, the non-foamed portion may have an average depth from the surface ranging from 0.05 to 5 mm. Examples of suitable foam having a non-foamed surface portion of the metal is an aluminum stabilized bubbles, self branch Alusion ^TM, Cymat commercially Technology Company, Toronto, Canada achieved.

Another way to improve the heat dissipation of the foamed metal may be, for example, using a duct to promote air circulation via the foam core without affecting the object The overall performance of the piece, such as retaining a closed outer casing to protect the enclosed component. This approach is particularly useful when using a non-foamed outer layer, ie where the cycle occurs only in the core by a carefully set channel.

When a polymer-based material is used to provide a defect-free or substantially defect-free surface, or to fill or at least partially fill the foamed structure for strength, the polymer-based material may It is from 0.05 mm to completely penetrate the thickness of the foamed metal (to form a through polymer-metal network). Examples of polymer-based materials for use in such embodiments include thermoset epoxy resins, or thermoplastic amorphous or crystalline polymers. In one embodiment, the polymer-based material is a thermoset epoxy resin. The polymer based material can be applied to a surface area or into the structure of the foamed metal using methods known or later discovered in any field. For example, the application can be formed by vacuum casting or pressure impregnation, or by compression molding with a thermoplastic material under pressure. The polymeric material can itself be filled with a suitable filler to reduce density, thermal strength, and/or thermal conductivity. The fillers may include ceria, quartz, alumina, boron nitride, aluminum nitride, graphite, carbon black, carbon nanotubes, aluminum flakes, fibers, glass fibers, glass or ceramic microspheres, and the like. A combination of two or more.

In various embodiments, the metal-based material can be a microsphere-filled metal. As used herein, the term "microspheres" means a filler material having a mass median diameter ("D50") of less than 500 microns ("μm"). Microsphere fillers suitable for use herein may generally have a spherical or substantially spherical shape. The metal of the microsphere-filled metal may be any of the metals described above. As indicated above, the metal-based material of the metal may be aluminum. Thus, in certain embodiments, the microsphere filled metal can be microsphere filled aluminum.

In various embodiments, the microsphere-filled metal can have a density ranging from 0.6 to 2 g/cm ³ . In addition, the microsphere-filled metal may have a thickness of from 5 to 150 W/m. The thermal conductivity of the range of K. Furthermore, the microsphere-filled metal may have a thickness of from 8 to 25 μm/m. The linear isotropic CTE of the range of K. In various embodiments, the microsphere filled metal can have a tensile strength ranging from 0.8 to 60 Kpsi (~5.5 to 413.7 MPa).

Various types of microsphere fillers can be used in the microsphere filled metal suitable for use herein. In various embodiments, the microsphere fillers are hollow. In addition, in some embodiments, the microspheres may be selected from the group consisting of glass microspheres, mullite microspheres, alumina microspheres, and aluminum-germanate microspheres (also known as hollow microspheres). (cenospheres), ceramic microspheres, ceria-carbon microspheres, carbon microspheres, and mixtures of two or more thereof.

In various embodiments, the microspheres suitable for use herein may have a particle size distribution D10 from 8 to 30 [mu]m. Additionally, the microspheres can have a D50 from 10 to 70 [mu]m. Again, the microspheres can have a D90 from 25 to 125 [mu]m. Further, the microspheres may have a true density ranging from 0.1 to 0.7 g/cm ³ . As is well known in the art, the "true" density is the density measured relative to the inter-particle gap space (as opposed to "bulk density"). The true density of the microspheres can be measured by a helium-substituted dry automated densitometer (e.g., Acupic 1330 from Shimadzu Corporation) as described in European Patent Application No. EP 1 156 021 A1. In addition, the microspheres suitable for use herein may have from 0.1 to 8 μm/m. The CTE of the range of K. Furthermore, suitable microspheres can have from 0.5 to 5 W/m. The thermal conductivity of the range of K. The microspheres can also be metal coated.

In various embodiments, the microspheres can be constructed from 1 to 95 volume percent ("vol%"), from 10 to 80 vol%, or from 30, based on the total volume of the microsphere-filled metal. To the range of 70 vol%.

In one or more embodiments, the microspheres are optionally combined with one or more types of conventional filler materials. Examples of conventional filler materials include ceria and alumina.

Commercially available microsphere-filled metals can be used in the various embodiments described herein. Examples of such commercially available one person to get from Powdermet Inc., Euclid, OH, USA of SComP ^TM.

In various embodiments, the microsphere-filled metal may have a surface region or a portion of the surface region that is (a) a metal that is not filled with microspheres, or (b) that is coated with a polymer-based material. cover. In such embodiments, the microsphere-filled metal may thus be present on a surface that is free or substantially free of defects (ie, smooth) that promotes metal plating and allows components that require a smooth surface (eg, heat sink) )Formation. When the surface area is non-microsphere filled, the non-microsphere filled portion may have an average depth from the surface in the range of 0.2 to 5 mm.

When a polymer-based material is used to provide a defect-free surface, the polymer-based material can be applied at a thickness ranging from 50 to 1,000 μm. The examples and methods in which the polymer-based materials are used in these embodiments are the same as those for the foamed metal as described above.

Wireless tower assembly

As noted above, any one or more of the above-described metal-based materials can be used to fabricate, at least in part, a wireless communication tower assembly. As used herein, "wireless communication tower assembly" means any telecommunications device, global positioning system ("GPS"), or similar device, or parts or portions thereof. Although the term "tower" is used, it should be noted that the device does not actually need to be installed or designed to be mounted on the tower; rather, other elevated positions such as radio, buildings, monuments, or trees may also be consider. Examples of such components include, but are not limited to, antennas, transmitters, receivers, transceivers, digital signal processors, control electronics, GPS receivers, power sources, and housings for electronic component housings. In addition, components commonly found in such electronic devices, such as RF filters and heat sinks, are also contemplated. Furthermore, tower top support fittings, such as platforms and mounting hardware, are also included.

As mentioned above, the wireless communication tower assembly can be an RF filter. An RF filter is a key component of a remote source. RF filters are used to eliminate signals at certain frequencies and are commonly used as building blocks for duplexers and diplexers to combine or separate a plurality of bandwidths. RF filters also play an important role in minimizing interference between systems operating in different bandwidths.

The RF cavity filter is an RF filter that is often used. A common practice in fabricating the various designs and physical geometries of such filters is to cast the aluminum mold into a desired structure or to create a final geometric configuration from a molded preform. The RF filter, its features, its processes, its machining, and the like, are described in, for example, U.S. Patent Nos. 7,847,658 and 8,072,298.

As noted above, polymer based materials can be used to provide a smooth surface on the metal based material and/or as a filler for metal based materials. For example, an epoxy composite material can be used to coat at least a portion of the surface of the metal-based material. Illustrative epoxy resin composites are described in U.S. Provisional Patent Application Serial No. 61/557,918 (the &apos; 918 Application). Alternatively, the metal-based material and/or the surface of the polymer-based material can be metallized as described in the '918 application.

In various embodiments, at least a portion of the metal-based material described above can be metal plated, as is typically the case with RF cavity filters. For example, a metal layer such as copper, silver or gold may be deposited on the metal-based material by various plating techniques, or interposed with a polymer-based material layer. Examples of suitable plating techniques can be found, for example, in the '918 application.

In an embodiment, the wireless communication tower assembly can be a heat sink. As is well known in the art, a heat sink, which can be a component for use with a remote radio head, typically includes a base member and a heat dissipating member (a "heat sink"). The heat dispersing element is typically formed from a highly conductive material such as copper. In one embodiment, a heat sink made in accordance with the present invention may comprise a base member formed from any of the above-described metal-based materials, using a conventional heat dissipating component. In various embodiments, when a foamed metal (especially an open foamed metal) is used, the base member can have a non-foamed surface as described above.

In various embodiments, the wireless communication tower component can be an included And/or protecting the outer casing of the electronic device. Examples of such enclosures may be, for example, the MRH-24605 LTE remote radio head from MTI Corporation.

In one or more embodiments, the wireless communication tower assembly can be a support member such as a mounting bracket or an assembly for manufacturing a platform. Specific components include, but are not limited to, antenna mounts, support brackets, co-location platforms, clamping systems, sector frame assemblies, ice bridge kits, three-sector T-mount components, light kit mounting systems, and waveguide bridges.

The above-described wireless communication tower assembly can be fabricated from such metal-based materials as described herein, according to any conventional or later discovered metalworking techniques, such as forming, blending, molding, machining, and the like. Combine and proceed.

testing method

density

The density of the composite samples was measured at 25 ° C according to ASTM D792. For samples of only metals, the density is measured by the density gradient method according to ASTM D1505.

Thermal conductivity

Thermal conductivity is measured according to ISO 22007-2 (Instantaneous Planar Heat Source (Hot Disc) Method).

Thermal expansion coefficient

CTE was measured using a thermomechanical analyzer (TMA 2940 from TA Instruments). An expansion profile is generated using a heating rate of 5 ° C / min, and the CTE is calculated as the slope of the expansion profile according to the following: CTE = ΔL / (ΔT x L) where ΔL is the length of the sample (μm Change, L is the The original length (m) of the sample, and ΔT is the change in temperature (°C). The temperature range in which the slope is measured is 20 ° C to 60 ° C on the second heating.

tensile strength

Tensile properties were measured according to ASTM D638 using a Type 1 stretch bar and a strain rate of 0.2 Torr/min on the cured epoxy resin formulation. For aluminum metal samples, tensile properties were measured according to ASTM B557M.

Glass transition temperature (Tg)

By heating the first heating scan from 0 to 250 ° C to a second heating scan from 0 to 250 ° C by heating the sample at a temperature of 10 ° C / min by placing the sample on a differential scanning calorimeter ("DSC"). Measure Tg. The Tg is reported as the half-height of the second-order transition on the second heating scan from 0 to 250 °C.

Instance Example 1 - Material Comparison

The foamed aluminum sample (S1) is combined with a conventional aluminum (Comp. A), three epoxy resin composite compositions (Comp. BD), and a glass-filled polyether phthalimide (Comp. E). Compare in Table 1 below. The foamed aluminum was a 25.4 mm thick sample having a density of 0.41 g/cm ³ and a predominantly open structure available from Cymat Technology Co., Ltd. The conventional aluminum is an aluminum alloy 6061. The mixing, casting and curing procedures for these epoxy resin composite compositions (Comp. BD) are generally carried out as follows. The warp filling of the glass is polyetherimide ULTEM ^TM 3452, polyetherimide having a glass fiber filler of 45%, commercially available from GE Plastics.

Comparative Example B-D Manufacturing Procedure

The words and names used in the following descriptions include: DEN425 is an epoxy resin having an EEW of 172 and is commercially available from The Dow Chemical Company; DER383 is an epoxy resin having an EEW of 171 and is commercially available from The Dow Chemical Company; "NMA" means nadic methyl anhydride and is available from Polysciences; "ECA100" means epoxy resin curing agent 100, purchased from Dixie Chemical, and ECA 100 typically contains greater than 80% methyl four. Hydrogen phthalic anhydride and greater than 10% tetrahydrophthalic anhydride; "1MI" means 1-methylimidazole and is available from Aldrich Chemical; SILBOND ^® W12EST is treated with epoxy decane having a D50 particle size of 16 μm Quartz, and is purchased from Quarzwerke.

The necessary amount of filler was dried overnight in a vacuum oven at a temperature of ~70 °C. The epoxy resin containing the anhydride hardener was pre-heated to ~60 °C. The designed amount of warm epoxy resin, warm anhydride hardener, and 1-methylimidazole, which was manually stirred by adding to the warm filler, was loaded into a wide-mouth plastic container. Then the contents of the container on a FlackTek SpeedMixer ^TM, during plural cycles from about 800 to about 2000rpm ~ 1-2 minutes of mixing.

The blended formulation is configured to a temperature-controlled 100-mL to 100-mL resin kettle with a top stirrer using a glass stirrer shaft with a Teflon® blade attached to the vacuum pump for degassing and Vacuum controller. A typical degassing profile is carried out at about 55 ° C and about 75 ° C, expressed as follows: 5 minutes, 80 rpm, 100 Torr; 5 minutes, 80 rpm, 50 Torr; 5 minutes, 80 rpm, 20 Torr, interrupted by N ₂ ~ 760Torr; 5 minutes and 80 rpm, 20 Torr, to N ₂ interrupt to ~ 760Torr; 3 minutes and 80 rpm, 20 Torr; for 5 minutes at 120 rpm, of 10 Torr; 5 minutes, 180rpm, 10Torr; 2 minutes 80 rpm, 20 Torr; and five minutes, 80 rpm, 30 Torr. Depending on the size of the degassed formulation, the use of a higher vacuum and a higher vacuum of 5 Torr can be optionally increased as needed.

The warm, degassed mixture is brought to atmospheric pressure and poured into the warm molded fitting described below. For the particular modes described below, some amounts between about 350 grams and 450 grams are typically poured into the open side of the mold. The filled mold was placed vertically in an oven at 80 ° C for about 16 hours, then the temperature was subsequently raised and maintained at 140 ° C for a total of 10 hours; then subsequently raised and maintained at 225 ° C for a total of 4 hours; and then slowly cooled to Ambient temperature (about 25 ° C).

Molded parts

Two ~ 355mm, while having a corner in the square metal plate cut ^{DUOFOIL TM (~ 330mm x 355mm x} ~ 0.38mm) are each secured thereon. A 3.05 mm thick U-shaped gasket and a rubber tube having a ~3.175 mm ID x~4.75 mm OD (as a gasket) are placed between the plates while the mold is held in close proximity to the C-clamp. The mold was preheated in an oven at approximately 65 °C prior to use. The same mold method can be used with a thicker U-shaped pad, and the silicone rubber tube is suitably adjusted as a gasket for casting with a smaller metal plate.

As shown in Table 1, the expanded aluminum provides a lower coefficient of thermal expansion than the thermoset, while maintaining proper thermal conductivity at a substantially reduced density compared to conventional aluminum.

Example 2 - Foamed Aluminum Filled with Thermosetting Epoxy Resin

The epoxy resin formulation will be filled once according to the following procedure A foamed aluminum block having a size of 2" x 2" x 0.5" was cast and cured. The epoxy resin formulation used was DER 332+50/50 norbornene methyl anhydride with 65 wt% SILBOND 126 EST / Epoxy curing agent 100 (ie, MTHPA). The foamed aluminum foam body is the same as in the above Example 1. After the epoxy resin composition is mixed and degassed as described above, the foamed aluminum is introduced into the resin. The liquid epoxy resin mixture in the kettle is maintained in a position to prevent it from floating by using a stirring blade. The vessel is closed and a vacuum is applied for 32 minutes as described below to remove air from the aluminum foam and drive the liquid epoxy into the liquid. Metal hole: 10torr 10min., 5torr 5min., 10torr 5min., 20torr 5min., and 30torr 5min. The container is then brought back to atmospheric pressure. A 550-mil thick U-shaped gasket is placed in the mold and Approximately 1/2 of the degassed mixture is poured into the mold assembly (as described above), the aluminum foam body of the inflation epoxy is then positioned and the remaining epoxy is poured onto the upper portion. Curing at 80 ° C for 16 hours, followed by 140 ° C for 10 hours, and finally at 200 ° C for 4 hours .

The obtained composite has an average density of 1.65 g/cm ³ and is from 23.6 to 29.4 μm/m. The average CTE of the range of K, and 5.1W/m. The linear isotropic thermal conductivity of K.

Claims (10)

A device comprising: a wireless communication tower assembly formed at least in part by a metal filled with microspheres, wherein the microsphere filled metal is measured at 25 ° C and has less than 2.7 grams per cubic centimeter ("g /cm ³ ") density. The device of claim 1, wherein the metal of the microsphere-filled metal is selected from the group consisting of aluminum, magnesium, and alloys thereof. The apparatus of claim 1 or 2, wherein the microsphere-filled metal has a thermal conductivity greater than 1 watt per metre ("W/m.K") as measured at 25 ° C, wherein the micro-transistor The ball-filled metal has a linear isotropic thermal expansion coefficient ("CTE") of less than 30 microns (" μm /m.K") per metre Kelvin temperature in the temperature range of -35 to 120 °C. A device according to any of the preceding claims, wherein the microsphere-filled metal is measured at 25 ° C and has a density in the range from 0.6 to 2 g/cm ³ , wherein the microsphere-filled metal is at 25 ° C. The measurement is from 5 to 150 W/m. KW/m. The thermal conductivity of K, wherein the foamed metal has a temperature ranging from -35 to 120 ° C, from 8 to 25 μ m / m. The linear isotropic CTE of the range of K. A device according to any of the preceding claims, wherein the microsphere filled metal has a tensile strength in the range from 0.8 to 60 Kpsi. The device of any of the preceding claims, wherein the microsphere-filled metal comprises a glass microsphere, mullite microspheres, oxygen selected from the group consisting of A group of microspheres composed of a mixture of aluminum microspheres, aluminum-niobate microspheres, ceramic microspheres, cerium oxide-carbon microspheres, carbon microspheres, and a mixture of two or more thereof. The device of claim 6, wherein the microspheres have a particle size distribution D10 ranging from 8 to 30 μm, a D50 ranging from 10 to 70 μm, and a D90 ranging from 25 to 120 μm, wherein the microspheres The ball has a true density ranging from 0.1 to 0.7 g/cm ³ . The device of claim 6, wherein the microspheres are comprised in a range from 1 to 95 volume percent based on the total volume of the microsphere-filled metal. The device of any of the preceding claims, wherein the wireless communication tower assembly is selected from the group consisting of a radio frequency ("RF") cavity filter, a heat sink, a housing, a tower support assembly, and the like. A group of combinations of people. The device of any of the preceding claims, wherein the wireless communication tower assembly is an RF cavity filter, wherein at least a portion of the microsphere filled metal is plated with copper and/or silver.