EMI absorption technology

Precision-engineered EMI absorption from MHz to THz.

Elect Nano engineers absorbing composites by controlling filler type, particle morphology, dispersion quality, interfacial polarization, electrical percolation, magnetic loss, dielectric loss, and matrix compatibility.

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Interactive RF spectrum

3 kHz to 3 THz frequency bands

Log-scaled spectrum map with ITU band designations, IEEE radar-frequency bands, representative applications, and wavelength conversion.

Hover or tab through any band
ITU
IEEE
Wave
100 km3 kHz
10 km30 kHz
1 km300 kHz
100 m3 MHz
10 m30 MHz
1 m300 MHz
100 mm3 GHz
10 mm30 GHz
1 mm300 GHz
100 µm3 THz

Electromagnetic absorption physics

Absorber design balances transmission, reflection, and internal loss.

Useful EMI absorption is not just high attenuation. The material should admit incident energy, dissipate it through dielectric, magnetic, and conductive loss paths, and avoid simply reflecting power back into the system.

Interactive absorption physics model

Electromagnetic absorption from complex material properties

Adjust complex permittivity, complex permeability, effective conductivity, and thickness to estimate absorber behavior from MHz through THz-adjacent frequencies. The stack plot separates transmitted, reflected, and absorbed power.

Absorber slab modelεᵣ* = ε′ − j(ε″ + σ/ωε₀)μᵣ* = μ′ − jμ″ with magnetic roll-offSEA = −10 log₁₀(T / (1 − R)); A = 1 − R − T
03060901201 MHz10 MHz100 MHz1 GHz10 GHz100 GHz1 THzAbsorption shielding effectiveness, SEA (dB)Frequency
20.8 GHzfrequency60.7 dBsimulated SEA56.8%absorbed powerR 43.2% / T 0.000048%surface coefficients
1000 kHz14.8 dBA 12.1% / μ″ 0.0085
1.02 GHz35.9 dBA 41.4% / μ″ 6.56
30.1 GHz63.4 dBA 57.1% / μ″ 0.91
294 GHz90 dBA 61.1% / μ″ 0.094

Model boundaries

This is a normal-incidence, homogeneous-slab, free-space model. It is useful for comparing absorber material levers, but it does not include backing conductors, Salisbury spacing, pyramidal geometry, anisotropy, edge effects, cavities, seams, or near-field source coupling.

Absorption shielding effectiveness removes the first-surface reflection term from the power balance. A highly reflective material can show low absorbed power even when total transmission is small.

Filler strategy

Traditional macrofillers and precision nanofillers solve different parts of the absorber problem.

Conventional absorbers are useful, but their electromagnetic response often comes with mass, loading, processability, and uniformity tradeoffs. Nanofiller systems give formulators a smaller length scale to tune the loss network.

Scanning electron microscope image of a macroscopic filler composite with large agglomerated particles and irregular micron-scale structures.

Macroscopic filler composite

Large particles and agglomerates can create local field concentration and nonuniform pathways.

Scanning electron microscope image of a precision nanofiller composite with nanoscale carbon nanotube networks between dispersed particles.

Precision nanofiller composite

Nanoscale networks add interfacial area and distributed lossy paths at much smaller length scales.

Ferrites and magnetic oxides

Permeability, magnetic relaxation, resonance behavior, and magnetic loss.

Graphite, carbon black, carbon fiber, metal particles

Conductive and dielectric loss through bulk conductivity, contact networks, and field concentration.

Loaded foams, sheets, elastomers, tapes, coatings, molded parts

Practical absorber formats that can work well, but are often limited by filler loading and geometry.

Macroscopic limitations

  • High loading can increase density, viscosity, brittleness, and processing difficulty.
  • Large particles and fibers can create anisotropy, agglomeration, local field concentration, inconsistent pathways, or nonuniform absorption.
  • Ferrite-heavy materials can add mass and may be less attractive where low density, thin sections, or nonmagnetic behavior are required.
  • Some systems perform well in a specific band but are difficult to tune broadly across MHz, GHz, and mmWave ranges.

Nanofiller contrast

  • dCNTs and graphene provide high aspect ratio, high intrinsic conductivity, large interfacial area, and low percolation thresholds.
  • Nanoscale dispersion tunes response through particle spacing, interface density, orientation, matrix selection, and hybrid filler design.
  • Engineered nanocomposites use distributed polarization and controlled loss pathways instead of relying only on bulk conductivity.

Effective medium and percolation

Absorption depends on the composite electromagnetic response, not just filler conductivity.

Dielectric composites are governed by complex permittivity, complex permeability, impedance matching, attenuation constant, and internal loss mechanisms. Effective medium behavior depends on filler loading, geometry, aspect ratio, orientation, dispersion, interfacial polarization, and contrast between filler and matrix properties.

The absorber target is usually controlled conductivity and dielectric loss while preserving impedance matching, so incident energy enters the material and is dissipated internally instead of being reflected at the surface.

MHz

Conductive network formation, resistive loss, and capacitive coupling between particles often dominate.

GHz and mmWave

Dielectric relaxation, Maxwell-Wagner-Sillars interfacial polarization, nanoscale gaps, tunneling/contact resistance, and distributed lossy networks become increasingly important.

Sub-THz / THz-facing

Filler geometry, nanoscale interfaces, matrix dielectric properties, and dispersion uniformity become more sensitive as wavelength, skin depth, and relaxation behavior change.

Product platform

THE TERmmINATOR™ 2 JUDGMENT Dk

Elect Nano’s engineered EMI absorbing material platform for high-performance RF, microwave, mmWave, space, defense, radar, and telecommunications applications.

  • Designed for demanding EMI absorption and RF energy dissipation.
  • Available in space-focused formulations when the matrix and qualification plan support the target mission environment.
  • Built around tunable dielectric loss, conductive loss, optional magnetic loss, and application-specific matrix selection.
  • Can be engineered for molded parts, sheets, inserts, coatings, bonded absorbers, conformal absorbers, or custom geometries.
Product detailsDownload TDS

THE TERmmINATOR™ 2 dielectric response

JUDGMENT Dk, 26.5-110 GHz

Select a trace to update the Y-axis to measured values. Hover or select a frequency point to inspect values.

Interactive THE TERmmINATOR™ 2 JUDGMENT Dk dielectric response graphInteractive chart of dielectric measurements from 26.5 to 110 GHz. The selected trace uses measured Y-axis values and points reveal values at each frequency.9.0010.0011.0012.0013.0030507090110epsilon primefrequency, GHzEpsilon prime measured values

Measured range

26.5-110GHz

dielectric measurement

epsilon prime

8.95-12.80

epsilon prime range

loss tangent

0.353-0.466

loss tangent range

epsilon double-prime

3.34-5.97

epsilon double-prime range

Waveguide terminations

RF loads

Standing wave suppressors

Stray signal absorbers

Cavity resonance dampers

Antenna-adjacent absorbers

Radar and telecom equipment absorbers

Satellite and low Earth orbit RF components

Test fixture and lab absorber components

Internal absorbers for enclosures and housings

Waveguide terminations, RF loads, Standing wave suppressors, Stray signal absorbers, Cavity resonance dampers, Antenna-adjacent absorbers, Radar and telecom equipment absorbers, Satellite and low Earth orbit RF components, Test fixture and lab absorber components, Internal absorbers for enclosures and housings

Matrix flexibility

One absorber technology, multiple production-ready material platforms.

The matrix controls processability, thermal stability, mechanical behavior, outgassing, environmental durability, adhesion, flexibility, toughness, and compatibility with the final part.

Elect Nano can help move from RF target requirements to material selection, formulation, prototyping, testing, and production-ready processing.

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Thermoplastics

Molded components, inserts, housings, and precision RF hardware.

Rubbers and elastomers

Pads, gaskets, conformal absorbers, and flexible interfaces.

Adhesives

Bonded absorbers and absorber-integrated assembly layers.

Coatings

Thin absorber layers on application-specific substrates.

Ceramic composites

Higher-temperature or dimensionally stable absorber inserts.

Hybrid organic/inorganic systems

Custom matrix packages for environmental, thermal, or RF constraints.

ProcessabilityThermal stabilityMechanical behaviorOutgassingEnvironmental durabilityAdhesionFlexibility and toughnessAtomic oxygen resistanceChemical resistanceManufacturability