1Barrier material & thickness

MaterialMatches this site's Busbar Calculator reference value. Non-magnetic.

Thickness (mm)

2Frequency & source

Frequency (Hz)1 MHz

Source field type

Far field (plane wave) applies once the shield is roughly a wavelength or more from the source. Closer in, use electric dipole for a high-voltage/low-current source (e.g. a PCB trace) or magnetic dipole for a low-voltage/high-current source (e.g. a current loop or busbar).

Results

Total shielding effectiveness

239.7dB

Absorption loss (A)

131.59dB

δ = 0.066 mm

Reflection loss (R)

108.15dB

Zw = 376.7 Ω, |Zs| = 3.69e-4 Ω

Multi-reflection correction (B)

-0dB

SE vs. frequency

Frequency	SE (dB)
100 Hz	140.8
1 kHz	140.8
10 kHz	141.3
100 kHz	159.8
1 MHz	239.7
10 MHz	514.3
100 MHz	1,404.1
1 GHz	4,239.5

Reference & assumptions

New to Schelkunoff / Ott Shielding Theory? Read the guide: EMC Shielding Effectiveness: How Schelkunoff's SE = A + R + B Works — a plain-language explainer of the standard behind this calculator.

Classical Schelkunoff decomposition SE = A + R + B for a solid, uninterrupted planar barrier. Absorption loss A = 8.686·(t/δ) reuses this site's Skin Depth Calculator's classical skin-depth formula directly. Reflection loss R = 20·log₁₀(Zw/(4·|Zs|)) compares the source field's wave impedance Zw against the shield's own intrinsic impedance |Zs| = √(ωµ/σ) — 377Ω for a far-field plane wave, or a distance- and frequency-dependent value for a near-field electric-dipole (high-impedance) or magnetic-dipole (low-impedance) source. The multiple-reflection correction B only matters for thin/high-frequency barriers (A below roughly 15dB) and is otherwise negligible. This model covers a solid barrier only — real enclosures are almost always limited by apertures, seams, and cable penetrations rather than the solid wall (see the companion Aperture & Vent Leakage calculator), and by cavity resonance at specific frequencies (see the Enclosure Cavity Resonance calculator).

Validated: cross-checked the reflection/absorption/multiple-reflection formulas against two independent sources (calcengineer.com's explicit-unit Zw/Zs formulation and learnemc.com's Ott/Schelkunoff textbook equations) — both reduce to the same expressions once reconciled. Verified numerically: 1mm copper at 1MHz (plane wave) gives A=131.6dB, R=108.2dB matching hand calculation exactly; the near-field electric- and magnetic-dipole wave-impedance formulas satisfy the required physical identity Zw(E)·Zw(H) = Z₀² at every frequency/distance, and both converge to the 377Ω far-field impedance at the classical near-field/far-field boundary r = λ/(2π).

Calculation steps

1. Skin depth & absorption loss

δ = √(ρ / (π·f·µ₀·µr)); A = 8.686·(t/δ)

Copper (annealed, 100% IACS): ρ = 0.0172 Ω·mm²/m, µr = 1, f = 1 MHz, t = 1 mm

δ = 0.066 mm → A = 131.59 dB

2. Shield intrinsic impedance

|Zs| = √(ωµ / σ)

ω = 2π·f, µ = µ₀·µr, σ = 1/ρ

|Zs| = 3.685e-4 Ω

3. Wave impedance of the source field

Zw = 377 Ω (far-field plane wave)

Zw = 376.73 Ω

4. Reflection loss & multiple-reflection correction

R = max(0, 20·log₁₀(Zw / (4·|Zs|))); B = min(0, 10·log₁₀((1−x·cosθ)² + (x·sinθ)²)), x=10^(−A/10), θ=0.23026·A

R = 108.15 dB, B = -0 dB

5. Total shielding effectiveness

SE = A + R + B

SE = 239.7 dB

EMC Shielding Effectiveness Calculator