WO2020068780A1

WO2020068780A1 - Noise suppression absorbers

Info

Publication number: WO2020068780A1
Application number: PCT/US2019/052638
Authority: WO
Inventors: Paul F. Dixon; Jason L. Strader; Hoang Dinh DO; Richard N. Johnson
Original assignee: Laird Technologies, Inc.
Priority date: 2018-09-24
Filing date: 2019-09-24
Publication date: 2020-04-02

Abstract

Disclosed are exemplary embodiments of noise suppression absorbers, such as sprayable and paintable noise suppression absorbers and/or high dielectric low frequency (HDLF) noise suppressor coatings, etc.

Description

NOISE SUPPRESSION ABSORBERS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/735,786 filed September 24, 2018. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to noise suppression absorbers, such as sprayable and paintable noise suppression absorbers and/or high dielectric low frequency (HDLF) noise suppressor coatings, etc.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] A common problem in the operation of electronic devices is the generation of electromagnetic radiation within the electronic circuitry of the equipment. Such radiation may result in electromagnetic interference (EMI) or radio frequency interference (RFI), which can interfere with the operation of other electronic devices within a certain proximity. Without adequate shielding, EMI/RFI interference may cause degradation or complete loss of important signals, thereby rendering the electronic equipment inefficient or inoperable.

[0005] A common solution to ameliorate the effects of EMI/RFI is through the use of shields capable of absorbing and/or reflecting and/or redirecting EMI energy. These shields are typically employed to localize EMI/RFI within its source, and to insulate other devices proximal to the EMI/RFI source.

[0006] The term“EMI” as used herein should be considered to generally include and refer to EMI emissions and RFI emissions, and the term“electromagnetic” should be considered to generally include and refer to electromagnetic and radio frequency from external sources and internal sources. Accordingly, the term shielding (as used herein) broadly includes and refers to mitigating (or limiting) EMI and/or RFI, such as by absorbing, reflecting, blocking, and/or redirecting the energy or some combination thereof so that it no longer interferes, for example, for government compliance and/or for internal functionality of the electronic component system.

DRAWINGS

[0007] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and is not intended to limit the scope of the present disclosure.

[0008] FIG. 1 is a line graph of permeability versus frequency in megahertz (MHz) for sprayable and paintable noise suppressor according to an exemplary embodiment.

DETAILED DESCRIPTION

[0009] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0010] Disclosed herein are exemplary embodiments of noise suppression absorbers, such as sprayable and paintable noise suppression absorbers and/or high dielectric low frequency (HDLF) noise suppressor coatings, etc.

[0011] For example, exemplary embodiments disclosed herein include low frequency noise suppressors that may be used as sprayable, paintable solutions with high permeability. A sprayable solution may include a resin system (e.g., polyurethane resin, etc.) and magnetic filler (e.g., magnetic metal power, etc.). The solution is configured or modified with the solvent such that the solution is capable of being coated, painted, sprayed, etc. onto a complexly shaped surface, e.g., a cable or other non-flat curved surface, etc. A centrifuge speed mixer may be used to mix the resin system and magnetic filler.

[0012] The sprayable solution may be configured for use as a low end noise suppressor with permeability from 20 to 40 at 10 megahertz (MHz). The low end noise suppressor may be sprayed or painted onto a metal ground, an electrically-conductive fabric (e.g., nickel plated polyester or taffeta fabric, or nickel/copper plated knit mesh, or nylon ripstop (NRS) fabric coated with nickel and/or copper, etc.), etc. to thereby provide improved and/or good noise absorption in the frequency range from 10 MHz to 2 gigahertz (GHz).

[0013] In exemplary embodiments, the resin system may comprise a polyurethane resin such as SOLUCOTE 6629, etc. SOLUCOTE 6629 is an aliphatic polyurethane in a solvent blend of toluene, isopropyl alcohol (IPA), and dimethylformamide (DMF). In other exemplary embodiments, the resin system may comprise VITON polymer, etc. VITON polymer is a synthetic rubber and fluoropolymer elastomer. Other resin systems may be used in alternative embodiments, such as silicone, various flexible plastics, other urethane or polymer resins, etc.

[0014] In exemplary embodiments, the magnetic filler may comprise high permeability magnetic metal power, such as SENDUST magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum. In exemplary embodiments, the coating solution may include magnetically permeable particles that can have real magnetic permeability from 20 up to 40 at 10 MHz. Additional or other fillers may be used in alternative embodiments, such as fillers having magnetic or dielectric absorption properties including silicon carbide (SiC), carbon black, etc.

[0015] In exemplary embodiments disclosed herein, the noise suppression absorber includes shaped (e.g., flattened, flaked, etc.) particles as the absorptive filler in the resin system. A solvent coating process may be used for a noise suppression absorber such that the absorptive particles are aligned in the XY plane of the absorber. In exemplary embodiments disclosed herein, however, a spray coat process is used for a noise suppression absorber where the spray coat process aligns and orients the absorptive particles in the XY plane. The absorptive particle alignment greatly increases the electromagnetic loss parameters. In addition to helping ensure that the shaped (e.g., flaked, flattened, etc.) absorber particles are made to align in the XY plane, the spray coating process may also enable placement of spray coatings on complex surfaces (e.g., PCB surfaces, etc.) in a manual or automated process.

[0016] Exemplary embodiments of sprayable and paintable noise suppression absorbers may include a weight percent magnetic filler loading from about 50 percent to about 70 percent, a volume percent magnetic filler loading from about 15 percent to about 20 percent, a real permeability at 1 MHz greater than 50, and a real permeability at 10 MHz greater than 20. In such exemplary embodiments, a centrifuge speed mixer may be used. The magnetic filler comprises magnetic metal powder (e.g., SENDUST magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum, etc.). The resin system comprises polyurethane resin (e.g., polyurethane SOLUCOTE 6629, etc.) or other polymer (e.g., VITON polymer, etc.).

[0017] In a first example formulation of a sprayable and paintable noise suppression absorber, the resin system included polyurethane SOLUCOTE 6629, and the magnetic filler included a first type of SENDUST magnetic metal powder. The weight percent of the magnetic filler loading was 56 percent, and the volume percent of the magnetic filler loading was 15 percent. For this first example formulation, the sprayable and paintable noise suppression absorber had a real permeability at 1 MHz of 60 and a real permeability at 10 MHz of 35.

[0018] In a second example formulation a sprayable and paintable noise suppression absorber, the resin system included polyurethane SOLUCOTE 6629, and the magnetic filler included a second type of SENDUST magnetic metal powder. The weight percent of the magnetic filler loading was 56 percent, and the volume percent of the magnetic filler loading was 15 percent. For this second example formulation, the sprayable and paintable noise suppression absorber had a real permeability at 1 MHz of 70 and a real permeability at 10 MHz of 50.

[0019] In a third example formulation of a sprayable and paintable noise suppression absorber, the resin system included polyurethane SOLUCOTE 6629, and the magnetic filler included a third type of SENDUST magnetic metal powder. The weight percent of the magnetic filler loading was 56 percent, and the volume percent of the magnetic filler loading was 15 percent. For this third example formulation, the sprayable and paintable noise suppression absorber had a real permeability at 1 MHz of 65 and a real permeability at 10 MHz of 50.

[0020] Viscosity of a sprayable and paintable noise suppressor may be controlled by varying the amount of solvent. In exemplary embodiments, the viscosity may be from about 1000 centipoise (cps) to about 15000 cps, etc. The sprayed or coated absorber thickness may be relatively thin, such as from about 3 mils up to about 5 mils, etc. The relatively thin absorber layer may have permeability up to 30 at 10 MHz.

[0021] In exemplary embodiments, a high dielectric low frequency (HDLF) coating solution includes magnetically permeable particles having real magnetic permeability from 20 up to 40 at 10 MHz. The HDLF coating solution may be used as a nearfield noise suppression on compound surfaces where a flat sheet elastomer or thin noise suppressor sheet may not desirable. For example, the HDLF coating solution may be used for coating a cable. The HDLF coating solution may have a magnetic permeability up to 40 at 10 MHz.

[0022] The HDLF coating solution may comprise soft magnetic filler of ferrite and magnetic metal powder ( e.g ., SENDUST magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum, etc.). The magnetic filler may be loaded in urethane (e.g., polyurethane, etc.) or polymer (e.g., VITON synthetic rubber and fluoropolymer elastomer, etc.) to thereby provide a thixotropic coating that can be brushed on or sprayed on using common spray equipment. The thickness of the HDLF coating may vary, such as from about 0.005 inches up to about 0.020 inches, etc. Magnetic permeability (m’) may vary from about 20 up to about 40 at 10 MHz. The HDLF solution may comprise a room temperature curing coating for nearfield noise suppression effective from 20 MHz to 2 GHz.

[0023] By way of background, some conventional noise absorbers may only be available as flat sheets, such as a flat sheet with pressure sensitive adhesive (PSA) for attachment. But the flat sheet configuration limits the ability to place the absorptive material very close to radiating sources for suppression of EMI in the near field of the radiating sources. For example, application of a flat sheet absorber around a cable or on a complex surface ( e.g ., complexly curved surface, other non-flat surface, etc.) adjacent a radiating source may leave gaps through which EMI may leak. Exemplary embodiments disclosed herein may advantageously provide sprayable and paintable noise suppression absorbers that may be more amendable to process automation and/or that may be coated, painted, sprayed, etc. onto complex surfaces. In exemplary embodiments, a sprayable and paintable noise suppression absorber may be painted or sprayed to thereby provide a shielding material having high permeability up to 40 at 10 MHz, which can help to solve noise problems in RF devices, etc.

[0024] In exemplary embodiments, a sprayable and paintable noise suppression absorber may be used (e.g., sprayed, painted, brushed, or coated onto, etc.) with a thermal interface material. In such exemplary embodiments, a wide range of thermal interface materials may be used. Example thermal interface materials include thermal gap fillers, thermal phase change materials, thermally- conductive EMI absorbers or hybrid thermal/EMI absorbers, thermal greases, thermal pastes, thermal putties, dispensable thermal interface materials, thermal pads, etc.

[0025] In exemplary embodiments, a sprayable and paintable noise suppression absorber may be sprayed, painted, brushed, or otherwise coated on a board level shield. In such exemplary embodiments, a wide range of materials may be used for the board level shield (broadly, shield) or portion thereof, such as cold rolled steel, nickel-silver alloys, copper-nickel alloys, stainless steel, tin plated cold rolled steel, tin-plated copper alloys, carbon steel, brass, copper, aluminum, copper- beryllium alloys, phosphor bronze, steel, alloys thereof, a plastic material coated with electrically- conductive material, or any other suitable electrically-conductive and/or magnetic materials. The materials disclosed in this application are provided herein for purposes of illustration only as different materials may be used depending, for example, on the particular application.

[0026] In exemplary embodiments, a noise suppression absorber may be sprayed, painted, brushed, or otherwise coated onto a thermal conductor (e.g., conductive fabric, metal ground, board level shield, thermal interface material, etc.) with a relatively high thermal conductivity. In such embodiments, the thermal conductor having the noise suppression absorber thereon may be used to define or provide part of a thermally-conductive heat path from a heat source to a heat removal/dissipation structure or component. The thermal conductor having the noise suppression absorber thereon may be used, for example, to help conduct thermal energy ( e.g ., heat, etc.) away from a heat source of an electronic device. The thermal conductor having the noise suppression absorber thereon may be positionable generally between a heat source and a heat removal/dissipation structure or component to establish a thermal joint, interface, pathway, or thermally-conductive heat path along which heat may be transferred (e.g., conducted) from the heat source to the heat removal/dissipation structure or component. During operation, the thermal conductor having the noise suppression absorber thereon may function to allow transfer of heat from the heat source along the thermally-conductive path to the heat removal/dissipation structure or component.

[0027] Exemplary embodiments are disclosed of noise suppression absorbers that comprise a resin system, absorptive filler within the resin system, and a solvent. The solvent modifies the resin system including the absorptive filler therein to be capable of being sprayed, painted, brushed, and/or coated onto a surface.

[0028] The resin system may comprise polyurethane resin including an aliphatic polyurethane in a solvent blend of toluene, isopropyl alcohol (IP A), and dimethylformamide (DMF); or synthetic rubber and fluoropolymer elastomer; or a silicone resin system.

[0029] The absorptive filler may comprise magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum; and/or magnetically permeable particles having real magnetic permeability from about 20 up to about 40 at a frequency of about 10 megahertz (MHz); and/or silicon carbide (SiC); and/or carbon black.

[0030] The absorptive filler may comprise absorptive particles in the resin system that are aligned in an XY plane of the noise suppression absorber. The absorptive particles comprise flattened, flaked, and/or shaped absorptive particles in the resin system may be aligned and oriented in an XY plane of the noise suppression absorber via a solvent coating process or a spray coating process, whereby the absorptive particle alignment allows for increased electromagnetic loss parameters.

[0031] A weight percent of the absorptive filler loading may be from about 50 percent to about 70 percent. A volume percent of the absorptive filler loading may be from about 15 percent to about 20 percent. The noise suppression absorber may have a real permeability at 1 MHz greater than 50 and a real permeability at 10 MHz greater than 20.

[0032] The resin system may comprise a polyurethane resin including an aliphatic polyurethane in a solvent blend of toluene, isopropyl alcohol (IPA), and dimethylformamide (DMF). The absorptive filler may comprise magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum. A weight percent of the absorptive filler loading may be about 56 percent. A volume percent of the absorptive filler loading may be about 15 percent. The noise suppression absorber may have a real permeability at 1 MHz of about 60 and a real permeability at 10 MHz of about 35; or a real permeability at 1 MHz of about 70 and a real permeability at 10 MHz of about 50; or a real permeability at 1 MHz of about 65 and a real permeability at 10 MHz of about 50.

[0033] The viscosity of the noise suppression absorber is controllable by varying an amount of the solvent. The viscosity of the noise suppression absorber may be within a range from about 1000 centipoise (cps) to about 15000 cps. The noise suppression absorber may be configured to be sprayed, painted, brushed, and/or coated onto a surface at a thickness including from about 3 mils up to about 5 mils. The noise suppression absorber may be configured to have a permeability up to about 30 at 10 MHz.

[0034] The absorptive filler may comprise magnetically permeable particles having real magnetic permeability from about 20 up to about 40 at 10 MHz. The noise suppression absorber may comprise a high dielectric low frequency coating solution having a magnetic permeability up to about 40 at 10 MHz and/or that is usable as a nearfield noise suppression on compound surfaces.

[0035] The noise suppression absorber may comprise a high dielectric low frequency coating. The absorptive filler may comprise ferrite and magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum. The resin system may comprise polyurethane or polymer. The high dielectric low frequency coating may be thixotropic and/or capable of being sprayed, painted, brushed, and/or coated onto a surface at a thickness including from about 0.005 inches up to about 0.020 inches. The high dielectric low frequency coating may have a magnetic permeability from about 20 up to about 40 at 10 MHz. The high dielectric low frequency coating may comprise a room temperature curing coating for nearfield noise suppression effective from about 20 MHz to about 2 GHz.

[0036] The noise suppressor may be configured for use as a sprayable and/or paintable low frequency noise suppressor having high permeability. The noise suppressor may be configured for use as a sprayable and/or paintable noise suppressor having a permeability from about 20 to about 40 at a frequency of about 10 megahertz (MHz). The noise suppressor may be sprayable and/or paintable onto a surface of a metal ground and/or an electrically-conductive fabric to thereby provide improved and/or good noise absorption in a frequency range from about 10 MHz to about 2 gigahertz (GHz).

[0037] A board level shield may include a portion defining a surface and the noise suppression absorber sprayed, painted, brushed, and/or coated along the surface of the portion of the board level shield.

[0038] A thermal interface material may comprise a portion defining a surface and the noise suppression absorber sprayed, painted, brushed, and/or coated along the surface of the portion of the thermal interface material.

[0039] Also disclosed are exemplary methods of providing noise suppression absorbers as disclosed herein. In an exemplary embodiment, a method includes mixing absorptive filler within a resin system to thereby provide a mixture including the resin system and the absorptive filler, and adding solvent to modify the mixture including the resin system and the absorptive filler such that the modified mixture is capable of being sprayed, painted, brushed, and/or coated onto a surface. The method may further include spraying, painting, or brushing the modified mixture including the resin system and the absorptive filler, as modified by the solvent, onto a complexly shaped surface and/or a surface of a printed circuit board in a manual or automated process. The method may include using a centrifuge speed mixer to mix the resin system and the absorptive filler.

[0040] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are 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 neither should be construed to limit the scope of the disclosure. In some example embodiments, well- known processes, well-known device structures, and well-known technologies are not described in detail. In addition, advantages and improvements that may be achieved with one or more exemplary embodiments of the present disclosure are provided for purpose of illustration only and do not limit the scope of the present disclosure, as exemplary embodiments disclosed herein may provide all or none of the above mentioned advantages and improvements and still fall within the scope of the present disclosure.

[0041] Specific dimensions, specific materials, and/or specific shapes disclosed herein are example in nature and do not limit the scope of the present disclosure. The disclosure herein of particular values and particular ranges of values for given parameters are not exclusive of other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is envisioned that any two particular values for a specific parameter stated 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 can be interpreted as disclosing that any value between the first and second values could also be employed for the given parameter). For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that parameter X may have a range of values from about A to about Z. Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if parameter X is exemplified herein to have values in the range of 1 - 10, or 2 - 9, or 3 - 8, it is also envisioned 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.

[0042] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, when permissive phrases, such as “may comprise”,“may include”, and the like, are used herein, at least one embodiment comprises or includes the feature(s). 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,” “comprising,”“including,” and“having,” 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.

[0043] When an element or layer is referred to as being“on”,“engaged to”,“connected to” or“coupled to” another element or layer, it may 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 to”,“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 a like fashion ( e.g .,“between” versus“directly between,”“adjacent” versus“directly adjacent,” etc.). As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items.

[0044] The term “about” when applied to values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the 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 arise from ordinary methods of measuring or using such parameters. For example, the terms“generally”,“about”, and“substantially” may be used herein to mean within manufacturing tolerances. Or for example, the term“about” as used herein when modifying a quantity of an ingredient or reactant of the invention or employed refers to variation in the numerical quantity that can happen through typical measuring and handling procedures used, for example, when making concentrates or solutions in the real world through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients employed to make the compositions or carry out the methods; and the like. The term“about” also encompasses amounts that differ due to different equilibrium conditions for a composition resulting from a particular initial mixture. Whether or not modified by the term“about”, equivalents to the quantities are included.

[0045] 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 or order 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.

[0046] Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) 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.

[0047] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements, intended or stated uses, or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied 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

CLAIMS WHAT IS CLAIMED IS:

1. A noise suppression absorber comprising a resin system, absorptive filler within the resin system, and a solvent that modifies the resin system including the absorptive filler therein to be capable of being sprayed, painted, brushed, and/or coated onto a surface.

2. The noise suppression absorber of any one of the preceding claims, wherein the resin system comprises:

polyurethane resin including an aliphatic polyurethane in a solvent blend of toluene, isopropyl alcohol (IP A), and dimethylformamide (DMF); or

synthetic rubber and fluoropolymer elastomer; or

a silicone resin system.

3. The noise suppression absorber of any one of the preceding claims, wherein the absorptive filler comprises:

magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum; and/or

magnetically permeable particles having real magnetic permeability from about 20 up to about 40 at a frequency of about 10 megahertz (MHz); and/or

silicon carbide; and/or

carbon black.

4. The noise suppression absorber of any one of the preceding claims, wherein the absorptive filler comprises absorptive particles in the resin system that are aligned in an XY plane of the noise suppression absorber.

5. The noise suppression absorber of claim 4, wherein the absorptive particles comprise flattened, flaked, and/or shaped absorptive particles in the resin system that are aligned and oriented in an XY plane of the noise suppression absorber via a solvent coating process or a spray coating process, whereby the absorptive particle alignment allows for increased electromagnetic loss parameters.

6. The noise suppression absorber of any one of the preceding claims, wherein:

a weight percent of the absorptive filler loading is from about 50 percent to about 70 percent; a volume percent of the absorptive filler loading is from about 15 percent to about 20 percent; the noise suppression absorber has a real permeability at 1 MHz greater than 50; and

the noise suppression absorber has a real permeability at 10 MHz greater than 20.

7. The noise suppression absorber of any one of the preceding claims, wherein:

the resin system comprises a polyurethane resin including an aliphatic polyurethane in a solvent blend of toluene, isopropyl alcohol (IP A), and dimethylformamide (DMF);

the absorptive filler comprises magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum;

a weight percent of the absorptive filler loading is about 56 percent; and

a volume percent of the absorptive filler loading is about 15 percent.

8. The noise suppression absorber of claim 7, wherein the noise suppression absorber has: a real permeability at 1 MHz of about 60 and a real permeability at 10 MHz of about 35; or a real permeability at 1 MHz of about 70 and a real permeability at 10 MHz of about 50; or a real permeability at 1 MHz of about 65 and a real permeability at 10 MHz of about 50.

9. The noise suppression absorber of any one of the preceding claims, wherein:

viscosity of the noise suppression absorber is within a range from about 1000 centipoise (cps) to about 15000 cps; and/or

the noise suppression absorber is configured to be sprayed, painted, brushed, and/or coated onto a surface at a thickness including from about 3 mils up to about 5 mils; and/or

the noise suppression absorber is configured to have a permeability up to about 30 at 10 MHz.

10. The noise suppression absorber of any one of the preceding claims, wherein:

the absorptive filler comprises magnetically permeable particles having real magnetic permeability from about 20 up to about 40 at 10 MHz; and/or the noise suppression absorber comprises a high dielectric low frequency coating solution having a magnetic permeability up to about 40 at 10 MHz and/or that is usable as a nearfield noise suppression on compound surfaces.

11. The noise suppression absorber of any one of the preceding claims, wherein the noise suppression absorber comprises a high dielectric low frequency coating.

12. The noise suppression absorber of claim 11, wherein:

the absorptive filler comprises ferrite and magnetic metal powder having a composition of 85% iron, 9.5% silicon, and 5.5% aluminum;

the resin system comprises polyurethane or polymer;

the high dielectric low frequency coating is thixotropic and/or capable of being sprayed, painted, brushed, and/or coated onto a surface at a thickness including from about 0.005 inches up to about 0.020 inches;

the high dielectric low frequency coating has a magnetic permeability from about 20 up to about 40 at 10 MHz; and

the high dielectric low frequency coating comprises a room temperature curing coating for nearfield noise suppression effective from about 20 MHz to about 2 GHz.

13. The noise suppression absorber of any one of the preceding claims, wherein:

the noise suppressor is configured for use as a sprayable and/or paintable low frequency noise suppressor having high permeability; and/or

the noise suppressor is configured for use as a sprayable and/or paintable noise suppressor having a permeability from about 20 to about 40 at a frequency of about 10 megahertz (MHz); and/or the noise suppressor is sprayable and/or paintable onto a surface of a metal ground and/or an electrically-conductive fabric to thereby provide improved and/or good noise absorption in a frequency range from about 10 MHz to about 2 gigahertz (GHz).

14. A board level shield comprising a portion defining a surface and the noise suppression absorber of any one of the preceding claims sprayed, painted, brushed, and/or coated along the surface of the portion of the board level shield.

15. A thermal interface material comprising a portion defining a surface and the noise suppression absorber of any one of claims 1 to 13 sprayed, painted, brushed, and/or coated along the surface of the portion of the thermal interface material.

16. A method of providing the noise suppression absorber of any one of claims 1 to 13, the method comprising:

mixing the absorptive filler within the resin system to thereby provide a mixture including the resin system and the absorptive filler; and

adding solvent to modify the mixture including the resin system and the absorptive filler such that the modified mixture is capable of being sprayed, painted, brushed, and/or coated onto a surface.

17. The method of claim 16, further comprising spraying, painting, or brushing the modified mixture including the resin system and the absorptive filler, as modified by the solvent, onto a complexly shaped surface and/or a surface of a printed circuit board in a manual or automated process.

18. The method of claim 16 or 17, wherein the method includes using a centrifuge speed mixer to mix the resin system and the absorptive filler.