Technical Insight
Reporting Frequency, Thickness, Geometry, Conductivity, and Absorption Without Misleading Claims
Report EMI shielding with frequency-resolved absolute results, complete specimen geometry, actual thickness, method-matched conductivity, explicit power-balance definitions, floor, repeats, and uncertainty.
Author: Aurexene Materials Engineering Team · Last updated: 2026-08-28
Quick Answer
Report the full target-frequency trace and absolute transmitted-power or total-shielding result; identify the verified floor and uncertainty; disclose the complete specimen, total and active-layer thickness, area, direction, contacts, edges, backing, conditioning, and test method; measure conductivity on a matched current path and state whether it is DC or frequency-dependent; and define every reflection or absorption quantity from a calibrated, closed power balance. A peak value, nominal thickness, unmatched conductivity number, or “absorption-dominant” label is not enough.
Problem
Two specimens can share a headline shielding value while differing in frequency band, local thickness, active material, substrate, area, direction, density, fixture floor, and transmitted power.
Selective peaks and undefined absorption terms can reverse a material decision. Reporting must preserve the measurement boundary, not just the most favorable number.
Mechanism
Shielding in dB is logarithmic. Report the complete frequency-resolved absolute result, its resolution, floor, repeatability, and uncertainty so a narrow resonance, ripple, fixture leak, or below-floor value is not presented as broadband performance.
Separate total specimen thickness from active coating or layer thickness and disclose substrates, adhesives, backing, porosity, density, area, orientation, contacts, edges, and conditioning. State whether a normalized figure uses mass, areal mass, density, total thickness, or active thickness; none replaces the absolute requirement.
Match electrical evidence to the shielding current path. DC, sheet, surface, through-thickness, bulk, and AC measurements require their own electrode, direction, geometry, thickness, frequency, temperature, and humidity metadata.
Use reflected, absorbed, and transmitted power only with disclosed equations, calibrated reference planes, valid ports and modes, and bounded leakage, scattering, radiation, support loss, and mode conversion. Power not measured as reflection is not automatically absorption in the material.
Tradeoff
A short headline helps scanning, but the underlying trace and conditions must remain visible. A normalized comparison can support mass or thickness optimization only after every option meets the absolute band and transmitted-power requirement.
More metadata increases review effort. A fixed reporting schema reduces that burden and prevents each chart from using a different denominator, thickness boundary, or absorption definition.
Material Strategy
Describe Multi-Walled Carbon Nanotubes (MWCNT), Few-Walled Carbon Nanotubes (FWCNT), and Single-Walled Carbon Nanotubes (SWCNT) as grade- and process-specific network candidates. Describe MXene, GNP, and Ionic-Liquid Exfoliated Graphene as grade- and process-specific flake or layer candidates.
Do not turn a product-class label or conductivity measurement into a shielding or absorption claim. Every result stays attached to the tested formulation, process, geometry, method, and state.
Recommended Architectures
| Claim element | Report | Reject |
|---|---|---|
| Frequency response | Full target band, resolution, raw and processed trace, absolute transmission or shielding, floor, repeats, uncertainty | Single peak, favorable sub-band, clipped axis, smoothing without lineage, or values below the verified floor |
| Thickness and geometry | Total and active-layer thickness maps, area, shape, direction, density or porosity, substrate, backing, contacts, edges, conditioning | Nominal thickness alone or an undefined “film” or “coating” construction |
| Conductivity | Matched specimen, location, direction, electrodes, DC or AC method, frequency, thickness conversion, environment, uncertainty | An unmatched supplier, coupon, direction, or DC number used as a broadband mechanism proof |
| Reflection and absorption | Equations, normalization, calibrated ports and modes, all bounded channels, energy-balance closure, transmitted power | Calling one minus reflection “material absorption” when leakage, radiation, scattering, support loss, or mode conversion is unbounded |
| Normalized efficiency | Absolute result first, explicit dimensions and units, uncertainty and sensitivity to mass, density, or thickness denominator | A normalized maximum used to imply application compliance |
Measurement & Validation
- Predeclare the decision, target band, frequency resolution, absolute requirement, transmitted-power limit, any allowed normalization, and pass-fail rule.
- Freeze the method, fixture and modes, calibration and reference planes, specimen construction, total and active-layer thickness, area, direction, contacts, edges, support, conditioning, repeat plan, floor, and uncertainty method.
- Retain raw and processed frequency traces with smoothing, gating, baseline, correction, and exclusion history. Mark values at or below the usable floor instead of extending the numeric claim.
- Measure conductivity or impedance on the matched specimen path. Report electrode geometry, direction, frequency, thickness conversion, temperature, humidity, repeats, and uncertainty.
- For R-A-T interpretation, disclose equations and normalization, verify valid ports and modes, bound all other loss channels, test energy-balance closure, and report absolute transmission alongside any derived term.
- Confirm the claim on a representative subassembly or system before extending a coupon result to the installed application.
Qualification Boundary
Freeze the approved claim text, audience and decision, complete frequency band and resolution, raw-data lineage, chart processing, absolute and normalized quantities, equations, definitions, dimensions and units, method and fixture, modes, calibration and reference planes, leakage and dynamic-range floor, specimen lot and construction, total and active thickness maps, area, shape, direction, density or porosity, contacts, edges, backing and support, conditioning and aging, electrical method and electrodes, R-A-T balance assumptions, repeats, uncertainty, correlated system state, and change-control owner.
Related Products
Related Applications
Related Comparisons
Downloads & Engineering Support
Both resources remain approval-required and cannot establish shielding, conductivity, reflection, absorption, transmission, or normalized performance.
- Request an EMI claim review
- Discuss measurement and reporting controls
- Discuss production evidence and change control
What to Validate
The reporting framework is engineering guidance. Confirm frequency-resolved shielding, conductivity, reflection, absorption, transmission, efficiency, or system performance until verified specimen-, method-, definition-, and application-specific evidence is available.
Need to apply this boundary to a grade, formulation, test method, or production route? Discuss it with the Aurexene Materials Engineering Team.