Patent Description:
The invention is defined by independent claims <NUM> and <NUM>.

This summary is provided solely as an introduction to subject matter that is fully described in the Detailed Description and Drawings.

<FIG> generally illustrate a system and method for shielding attenuation of electromagnetic interference (EMI) emissions, in accordance with one or more embodiments of the disclosure.

Select avionics equipment may be designed for Electromagnetic Compatibility (EMC) to reduce Electromagnetic Interference (EMI). The EMI may emanate from the select avionics equipment. For example, EMI emissions may cause issues with outside components. By way of another example, EMI emissions may cause weaknesses in security protocols by allowing access to a device such as operating information.

Testing for EMI may be costly to both a program requiring the select avionics equipment and to a company designing, manufacturing, and/or using the select avionics equipment. For example, EMI tests may be difficult and costly for companies to pinpoint signal propagation from these devices. By way of another example, avionics labs may be setup to run EMI testing on a specific module such that only when testing has finished with the first module can testing begin on another, resulting in significant costs and delays when EMI testing needs to be done more than one time for a circuit board module.

Designing for EMC may require costly calculations on circuit board modules. Due to the unpredictability during the design process, initial EMC designs may have a high probability of failure, increasing costs and design time. Repurposing and retrofitting components (e.g., circuit boards or modules) with pre-designed EMC characteristics may require significant redesign and costs. In some cases where the components are being repurposed, inflexibility in the design (e.g., as necessary to main EMI characteristics) may mean the designs are not modifiable.

As such, it would be beneficial to have a system and method for shielding attenuation of module emissions. The system should be able to be included in a new design. The system should also be able to be incorporated into an existing design to allow for repurposing and/or retrofitting components for the purpose of shielding attenuation.

<FIG> generally illustrate a system <NUM> for testing for electromagnetic interference (EMI) emissions, in accordance with one or more embodiments of the disclosure. <FIG> generally illustrate example embodiments of a subsystem of one or more subsystems <NUM> within the system <NUM>, in accordance with one or more embodiments of the disclosure.

The system <NUM> may include any stationary system. For example, the stationary system may include, but is not limited to, a structure or a sub-system configured to be attached to a structure. For instance, the structure may include, but is not limited to, a residential, commercial or industrial, or military establishment such as a home, a business, storage building, military building, or the like; a remote range device; or the like.

The system <NUM> may include any non-stationary system. For example, the non-stationary system may include, but is not limited to, a vehicle or a component configured to be attached to a vehicle. For instance, the vehicle may be any air, space, land, or water-based personal equipment or vehicle; any air, space, land, or water-based commercial or industrial equipment or vehicle; any air, space, land, or water-based military equipment or vehicle; or the like.

The one or more subsystems <NUM> may include, but are not limited to, one or more areas (e.g., pods, rooms, cabins, engine bays, defined cavities, or the like) within the system <NUM>. By way of another example, the one or more subsystems <NUM> may include, but are not limited to, a module <NUM>, one or more modules, one or more connectors of the one or more modules, one or more cables coupled to the one or more connectors of the one or more modules, or the like.

The system <NUM> may include one or more exterior subsystems <NUM> configured to receive an emitted electromagnetic interference (EMI) emission <NUM> from the one or more subsystems <NUM>. For example, in a testing environment, the one or more exterior subsystems <NUM> may include, but are not limited to, a network analyzer. By way of another example, in an operating environment, the one or more exterior subsystems <NUM> may include, but are not limited to, exterior components <NUM> or devices capable of being disrupted or otherwise affected by the EMI emission <NUM>. It is noted herein the receiving of the EMI emission <NUM> from the one or more subsystems <NUM> by the one or more exterior subsystems <NUM> may be intentional or unintentional with respect to the testing and/or operating of the one or more exterior subsystems <NUM>.

A module <NUM> may be designed or retrofitted for electromagnetic compatibility (EMC) to dampen the EMI emission <NUM> to a reduced EMI emission <NUM>. For example, the reduced EMI emission <NUM> may be of a significant magnitude of difference in terms of signal strength as compared to the EMI emission <NUM>. Attenuating the EMI emission <NUM> may include reflecting or absorbing at least a portion of the EMI emission <NUM> back into the module <NUM>. For example, the reflecting or absorbing of the EMI emission <NUM> back at a source of the EMI emission <NUM> may cause anti-resonance and ultimately negate the EMI emission <NUM>.

Designing or retrofitting the module <NUM> for EMC may include adding one or more shielding layers <NUM> to a structure <NUM> of the module <NUM>. The shielding layer <NUM> may reflect or absorb electromagnetic interference (EMI), acting as an EMI shield. For example, the EMI emission <NUM> emitted from inside the module <NUM> may be reflected or absorbed by the shielding layer <NUM>, attenuating the EMI emission <NUM> such that only the reduced EMI emission <NUM> is emitted by the module <NUM>. The shielding layer <NUM> may be configured to attenuate EMI emission <NUM> signal frequencies by absorbing the EMI emission <NUM> or reflecting the EMI emission <NUM> back at to the source (e.g., the one or more components <NUM>), causing anti-resonance and ultimately negation of the EMI emission <NUM>.

The structure <NUM> may include a chassis, a housing, a shell, or other structure capable of encasing or encompassing at least a portion of the one or more subsystems <NUM> and/or at least some components of one or more components <NUM>. The structure <NUM> may be fabricated with one or more portions. For example, as illustrated in <FIG>, the structure <NUM> may include a main body <NUM>, sidewalls <NUM>, and a lid <NUM>. For instance, the sidewalls <NUM> may be integrated with the main body <NUM> during fabrication. In addition, the sidewalls <NUM> may be coupled to the main body <NUM> during fabrication. By way of another example, the structure <NUM> may be fabricated as a single integrated unit including the main body <NUM>, the sidewalls <NUM>, and the lid <NUM>. It is noted herein the main body <NUM>, the one or more sidewalls <NUM> and/or the lid <NUM> may be coupled via an adhesive, fasteners, soldering, or other coupling mechanism.

The shielding layer <NUM> may line an exterior of the structure <NUM> or an interior of the structure <NUM>.

For example, as illustrated in <FIG>, <FIG>, and <FIG>, the shielding layer <NUM> may be exterior to the module <NUM>, such that the shielding layer <NUM> at least partially encases or encompasses the module <NUM>. For instance, the shielding layer <NUM> may be coupled to an exterior surface of the main body <NUM>, the sidewalls <NUM>, and/or the lid <NUM> of the structure <NUM>.

By way of another example, as illustrated in <FIG>, <FIG>, and <FIG>, the shielding layer <NUM> may be within of the module <NUM>, such that the module <NUM> at least partially encases or encompasses the shielding layer <NUM>. For instance, the shielding layer <NUM> may be coupled to an interior surface of the main body <NUM>, the sidewalls <NUM>, and/or the lid <NUM> of the structure <NUM>. In general, the shielding layer <NUM> may be, but is not limited to, a panel, placard, sticker, or other element configured to couple to a surface of the structure <NUM> and attenuate the EMI emission <NUM>. The shielding layer <NUM> may be coupled via an adhesive, fasteners, soldering, or other coupling mechanism. In this regard, a designed and fabricated structure <NUM> of the module <NUM> may be retrofitted with the shielding layer <NUM> by a manufacturer and/or by a customer post-manufacturing.

Although embodiments of the disclosure describe the shielding layer <NUM> being coupled to a surface of the structure <NUM> of the module <NUM>, it is noted herein the structure <NUM> of the module <NUM> may be fabricated at least in part from the shielding layer <NUM>. In addition, it is noted herein the shielding layer <NUM> may be at least partially embedded within the structure <NUM> of the module <NUM>. In this regard, a module <NUM> may be designed with the shielding layer <NUM> by a manufacturer and/or by a customer pre-manufacturing.

The system <NUM> may include one or more components <NUM> configured to emit the EMI emission <NUM>. For example, the one or more components <NUM> may include, but are not limited to, one or more circuit cards <NUM> or printed circuit boards <NUM> (PCB <NUM>) installed within the structure <NUM> of the one or more modules <NUM>, one or more connectors of the one or more circuit cards <NUM> installed within the structure <NUM> of the one or more modules <NUM>, one or more cables coupled to the one or more connectors of the one or more circuit cards <NUM> installed within the structure <NUM> of the one or more modules <NUM>, or the like. It is noted herein the combination of the module <NUM> and the circuit card <NUM> or PCB <NUM> may be considered a module assembly, circuit card assembly, or PCB assembly, for purposes of the present disclosure.

As illustrated in <FIG>, a PCB <NUM> may include one or more PCB layers <NUM>. In one example, where there are multiple PCB layers <NUM>, the PCB layers <NUM> may be separated by a PCB dielectric layer <NUM>. The PCB <NUM> may include one or more internal or embedded structures (i.e., internal PCB element <NUM>). For example, one or more PCB vias <NUM> may be embedded within (e.g., pass through) the PCB dielectric layer <NUM>, and may electrically couple the PCB layers <NUM> on either side of the PCB dielectric layer <NUM>. For instance, the PCB layers <NUM> adjacent to the PCB dielectric layer <NUM> may be electrically coupled. In addition, a PCB via <NUM> may be embedded within (e.g., pass through) at least one of the PCB layers <NUM> adjacent to the PCB dielectric layer <NUM>, such that non-adjacent PCB layers <NUM> may be electrically coupled.

The PCB <NUM> may include one or more external structures <NUM>. For example, the one or more external structures <NUM> (i.e., external PCB elements <NUM>) may include, but are not limited to, one or more external PCB passive devices <NUM> (e.g., resistors, or the like) or external active devices <NUM> (e.g., amplifiers, or the like). For example, the one or more PCB passive or active devices <NUM> may be coupled (e.g., physically and/or electrically) to a surface of the one or more PCB layers <NUM>. For instance, the one or more external PCB passive or active devices <NUM> may be coupled to a power or ground plate or layer <NUM> on an exterior surface of a PCB layer <NUM>. By way of another example, the one or more external PCB passive or active devices <NUM> may be embedded within the PCB <NUM> (e.g., embedded within a PCB dielectric layer <NUM> or between a PCB layer <NUM> and the PCB dielectric layer <NUM>).

A PCB <NUM> may be designed or retrofitted for electromagnetic compatibility (EMC) to dampen the EMI emission <NUM> emitted from internal PCB layers and/or internal vias and/or external PCB passive or active devices <NUM> embedded within the PCB <NUM> to a reduced EMI emission <NUM>. For example, the reduced EMI emission <NUM> may be of a significant magnitude of difference in terms of signal strength as compared to the EMI emission <NUM>. Attenuating the EMI emission <NUM> may include reflecting or absorbing at least a portion of the EMI emission <NUM> back into the PCB <NUM>. For example, the reflecting or absorbing of the EMI emission <NUM> back at a source of the EMI emission <NUM> may cause anti-resonance and ultimately negation of the EMI emission <NUM>.

Designing or retrofitting the PCB <NUM> for EMC may include adding one or more shielding layers <NUM> to the PCB <NUM>. As illustrated in <FIG>, <FIG>, and <FIG>, the shielding layer <NUM> may be placed on an exterior of the PCB <NUM>, such that the shielding layer <NUM> at least partially encases or encompasses the PCB <NUM>. For example, the shielding layer <NUM> may be coupled to an exterior surface of the PCB <NUM> (e.g., on a surface of an exterior PCB layer of the PCB <NUM>, or the like). In general, the shielding layer <NUM> may be, but is not limited to, a panel, placard, sticker, or other element configured to couple to a surface of the PCB <NUM> and attenuate the EMI emission <NUM>. For example, the shielding layer <NUM> may be coupled via an adhesive, fasteners, soldering, or other coupling mechanism. In this regard, a designed and fabricated PCB <NUM> may be retrofitted with the shielding layer <NUM> by a manufacturer and/or by a customer post-manufacturing.

Although embodiments of the disclosure describe the shielding layer <NUM> being coupled to a surface of the PCB <NUM>, it is noted herein the PCB <NUM> may be fabricated at least in part with the shielding layer <NUM>. For example, the shielding layer <NUM> may replace a PCB layer of the PCB <NUM>. By way of another example, the shielding layer <NUM> may be a PCB layer (e.g., a reference or ground layer <NUM>) repurposed to attenuate the EMI emission <NUM> or given an additional purpose of attenuating the EMI emission <NUM> (e.g., in addition to operating as the reference or ground layer <NUM>). In addition, it is noted herein the shielding layer <NUM> may be at least partially embedded within the PCB <NUM>. For example, the shielding layer <NUM> may be positioned between PCB layers. In this regard, a PCB <NUM> may be designed with the shielding layer <NUM> by a manufacturer and/or by a customer pre-manufacturing.

Although embodiments of the disclosure illustrate the shielding layer <NUM> being simultaneously coupled to (or integrated with) the main body <NUM>, the sidewalls <NUM>, and/or the lid <NUM> of the structure <NUM> for purposes of attenuating the EMI emissions <NUM>, it is noted herein the shielding layer <NUM> may be coupled to (or integrated with) only the main body <NUM>, the sidewalls <NUM>, or the lid <NUM> of the structure <NUM>. For example, the shielding layer <NUM> may not be needed for the main body <NUM> and/or the sidewalls <NUM> where the shielding layer <NUM> is coupled to (or integrated with) the lid <NUM> and the EMI emission <NUM> is directed through the lid <NUM>. Therefore, the above description should not be interpreted as a limitation on the scope of the present disclosure but merely an illustration.

Although embodiments of the disclosure illustrate the shielding layer <NUM> being simultaneously coupled to (or integrated with) the structure <NUM> and the PCB <NUM> for purposes of attenuating the EMI emissions <NUM>, it is noted herein the shielding layer <NUM> may be coupled to (or integrated with) only the structure <NUM> or the PCB <NUM>. For example, the shielding layer <NUM> may not be needed for the structure <NUM> where the shielding layer <NUM> is coupled to (or integrated with) the PCB <NUM>. Therefore, the above description should not be interpreted as a limitation on the scope of the present disclosure but merely an illustration.

In one example embodiment as illustrated in <FIG>, <FIG>, <FIG>, and <FIG>, the shielding layer <NUM> may be a metamaterial absorber <NUM>. The metamaterial absorber <NUM> may absorb at least a part of the EMI emission <NUM>, acting as an EMI shield. For example, the EMI emission <NUM> emitted from inside the module <NUM> may be absorbed in part by the metamaterial absorber <NUM>, attenuating the EMI emission <NUM> such that only the reduced EMI emission <NUM> is emitted. By way of another example, the metamaterial absorber <NUM> may be configured to cause anti-resonance and ultimately negation of the EMI emission <NUM>.

The metamaterial absorber <NUM> may include any material known in the art to absorb at least part of the EMI emission <NUM> to reduce the EMI emission <NUM>. The metamaterial absorber <NUM> may include assemblies of multiple elements <NUM> fabricated from composite materials including, but not limited to, metals or plastics. For example, the metamaterial absorber <NUM> may include, but is not limited to, graphene, copper, fiberglass, or a combination of materials. The elements <NUM> may be arranged in patterns (e.g., repeating or non-repeating patterns). For example, the patterns may be scaled smaller than the EMI emission <NUM> to be attenuated.

The elements <NUM> may include one or more adjustable fins <NUM>. Configurations of the elements <NUM> and the contained one or more fins <NUM> including, but not limited to, shape, size, orientation, geometry, arrangement, or the like may attenuate at least a part of the EMI emission <NUM>. The number and/or design of the adjustable fins <NUM> of the elements <NUM> may be determined based on the EMI emission <NUM>, either through modelling, testing, simulations, iterative trial-and-error, or the like.

The metamaterial absorber <NUM> may be designed for an EMI emission <NUM> and/or tunable in response to the EMI emission <NUM>, such that at least a part of the EMI emission <NUM> may be absorbed. The tuning of the one or more fins <NUM> may occur via circuitry installed within the module <NUM> and/or couplable to the module <NUM>. For example, the circuitry may include, but is not limited to, filters, modulators, amplifiers, transistors, resonators. The circuitry may be manually tuned or automatically tuned via a controller (e.g., a controller coupled to the exterior component <NUM> measuring the EMI emissions <NUM>) during the tuning process. The circuitry may be statically tuned (e.g., based on a measurement or a model of the EMI emission <NUM> prior to installation or after installation) or dynamically tuned (e.g., during the measurement of the EMI emission <NUM>).

It is noted herein the structure <NUM> may represent the bulk or majority of the weight of the module <NUM>. In addition, it is noted herein the structure <NUM> may be fabricated from a particular material of a select weight to shield against the EMI emission <NUM>, including having a thicker top, bottom, and/or sides. Where the shielding layer <NUM> such as the metamaterial absorber is used, the structure <NUM> may be differently designed. For example, the thickness of the top, bottom, and/or sides of the structure <NUM> may be reduced. By way of another example, the type of material from which the structure <NUM> may be changed to a lighter material. In this regard, the weight of the module <NUM> may be reduced.

<FIG> is a flow diagram illustrating a method <NUM> for shielding attenuation of module emissions, in accordance with one or more embodiments of the disclosure.

In a step <NUM>, a module or a component to be installed within a module may be fabricated. The module <NUM> may include a structure <NUM>. For example, the structure <NUM> may include the main body <NUM>, the sidewalls <NUM>, and/or the lid <NUM>. The component <NUM> may include a PCB <NUM>. In a step <NUM>, the module or the component to be installed within the module may be received.

In a step <NUM>, a frequency of an EMI emission emitted by the module or the component to be installed within the module may be determined. The EMI emission <NUM> may be emitted by the module <NUM> or by the component <NUM> to be installed within the module <NUM>. The EMI emission <NUM> may be measured by a component <NUM> exterior to the module <NUM>. For example, the exterior component <NUM> may include, but is not limited to, a network analyzer. A controller coupled to the network analyzer and/or circuity installed within and/or couplable to the module <NUM> may determine the frequency of the EMI emission <NUM>.

In a step <NUM>, a shielding layer may be coupled to the module or to the component installed within the module. The shielding layer <NUM> may include a metamaterial absorber. The shielding layer <NUM> may be coupled to an exterior surface of the structure <NUM> of the module <NUM>. The shielding layer <NUM> may be coupled to an interior surface of the structure <NUM> of the module <NUM>. The shielding layer <NUM> may be coupled to an exterior surface of the component <NUM>.

It is noted herein the order of steps <NUM> and <NUM> may be performed in either order.

In a step <NUM>, the shielding layer may be tuned to attenuate the emitted EMI emission. The tuning may be completed via the circuity installed within and/or couplable to the module <NUM>. The tuning may be manual or automatic via a controller. The tuning may be static or dynamic. It is noted herein the tuning may occur prior to or after the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>. For example, where the tuning occurs prior to the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>, the reduced EMI emission <NUM> may be measured following the coupling to ensure the tuning is correct. By way of another example, where the tuning occurs after the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>, the reduced EMI emission <NUM> may be measured periodically to ensure the tuning is correct.

It is noted herein step <NUM> may be optional. For example, a first party may fabricate the module <NUM> or the component <NUM> to be installed within the module <NUM> per step <NUM>. By way of another example, a second party may receive the module <NUM> or the component <NUM> to be installed within the module <NUM>, measure the EMI emission <NUM>, couple the shielding layer <NUM>, and tune the shielding layer <NUM> to attenuate the EMI emission <NUM> per steps <NUM>, <NUM>, <NUM>, and <NUM>. In addition, it is noted herein step <NUM> may be optional. For example, the same party may fabricate the module <NUM> or the component <NUM> to be installed within the module <NUM> per step <NUM>, and may measure the EMI emission <NUM>, couple the shielding layer <NUM>, and tune the shielding layer <NUM> to attenuate the EMI emission <NUM> per steps <NUM>, <NUM>, and <NUM>. Therefore, the above description should not be interpreted as a limitation on the scope of the present disclosure but merely an illustration.

In a step <NUM>, a module or one or more components to be installed within a module may be fabricated with a shielding layer. The module <NUM> may include a structure <NUM>. For example, the structure <NUM> may include the main body <NUM>, the sidewalls <NUM>, and/or the lid <NUM>. The component <NUM> may include a PCB <NUM>. The shielding layer <NUM> may include a metamaterial absorber. The shielding layer <NUM> may be coupled to an exterior surface of the structure <NUM> of the module <NUM>. The shielding layer <NUM> may be coupled to an interior surface of the structure <NUM> of the module <NUM>. The shielding layer <NUM> may be coupled to an exterior surface of the component <NUM>. In a step <NUM>, the module or the component to be installed within the module may be received.

In a step <NUM>, the shielding layer may be tuned to attenuate the emitted EMI emission. The tuning may be completed via circuity installed within and/or couplable to the module <NUM>. The tuning may be manual or automatic via a controller. The tuning may be static or dynamic. It is noted herein the tuning may occur prior to or after the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>. For example, where the tuning occurs prior to the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>, the reduced EMI emission <NUM> may be measured following the coupling to ensure the tuning is correct. By way of another example, where the tuning occurs after the coupling of the shielding layer <NUM> to the module <NUM> or to the component <NUM> installed within the module <NUM>, the reduced EMI emission <NUM> may be measured periodically to ensure the tuning is correct.

It is noted herein step <NUM> may be optional. For example, a first party may fabricate the module <NUM> or the component <NUM> to be installed within the module <NUM> with the shielding layer <NUM> per step <NUM>. By way of another example, a second party may receive the module <NUM> or the component <NUM> to be installed within the module <NUM>, measure the EMI emission <NUM>, and tune the shielding layer <NUM> to attenuate the EMI emission <NUM> per steps <NUM>, <NUM>, and <NUM>. In addition, it is noted herein step <NUM> may be optional. For example, the same party may fabricate the module <NUM> or the component <NUM> to be installed within the module <NUM> with the shielding layer <NUM> per step <NUM>, and may measure the EMI emission <NUM> and tune the shielding layer <NUM> to attenuate the EMI emission <NUM> per steps <NUM> and <NUM>. Therefore, the above description should not be interpreted as a limitation on the scope of the present disclosure but merely an illustration.

It is noted herein the methods or processes <NUM> and <NUM> is not limited to the steps and/or sub-steps provided. The methods or processes <NUM> and <NUM> may include more or fewer steps and/or sub-steps. In addition, the methods or processes <NUM> and <NUM> may perform the steps and/or sub-steps simultaneously. Further, the methods or processes <NUM> and <NUM> may perform the steps and/or sub-steps sequentially, including in the order provided or an order other than provided. Therefore, the above description should not be interpreted as a limitation on the scope of the disclosure but merely an illustration.

In this regard, including a tunable shielding layer <NUM> fabricated from a metamaterial absorber may reduce the number of design constraints on the module <NUM> (e.g., on the structure <NUM> of the module <NUM> and/or on the components <NUM> including, but not limited to, a PCB <NUM> installed within the module <NUM>). For example, the tunable shielding layer <NUM> fabricated from the metamaterial absorber may be the adjustment mechanism to attenuate emitted EMI signals <NUM> instead of needing to design the module <NUM> to be able to address emitted EMI emissions <NUM>. In addition, including the tunable shielding layer <NUM> fabricated from the metamaterial absorber may allow for retrofitting of modules <NUM> and/or components <NUM> including, but not limited to, a PCB <NUM> installed within the module <NUM> instead of scrapping the module due to the emitted EMI emissions <NUM>. Further, including a tunable shielding layer <NUM> fabricated from a metamaterial absorber may reduce the weight of the structure <NUM>, as a necessary thickness of structure walls may be reduced and replaced with the attenuating or shielding properties of the tunable shielding layer <NUM> fabricated from the metamaterial absorber.

It is noted herein that one or more components of the system <NUM> may need to be configured in accordance with aviation guidelines and/or standards put forth by, but not limited to, the Federal Aviation Administration (FAA), the European Aviation Safety Agency (EASA) or any other flight certification agency or organization; the American National Standards Institute (ANSI), Aeronautical Radio, Incorporated (ARINC), or any other standards setting organization or company; the Radio Technical Commission for Aeronautics (RTCA) or any other guidelines agency or organization; or the like.

Claim 1:
A printed circuit board, PCB, module (<NUM>) configured for shielding attenuation of an electromagnetic interference (EMI) emission, comprising:
a PCB (<NUM>) including:
at least one internal PCB element (<NUM>);
at least one external PCB element (<NUM>), the at least one internal PCB element being embedded between adjacent layers of the PCB; and
a first shielding layer (<NUM>) fabricated from a tunable first metamaterial absorber, the first shielding layer being tuned in response to at least one measurement of the EMI emission and a determination of a frequency of the EMI emission from the at least one measurement; the tuning of the first shielding layer including determining, based on the EMI emission (<NUM>), the number and/or design of a plurality of adjustable fins (<NUM>) of a plurality of elements (<NUM>) of the first metamaterial absorber; the first shielding layer being configured to absorb at least a portion of the EMI emission following the tuning of the first shielding layer, the first shielding layer being a ground layer (<NUM>) of the PCB located below the at least one external PCB element, the at least one external PCB element and the at least one internal PCB element being coupled to the first shielding layer; and
a structure (<NUM>) housing the PCB.