Electromagnetic Shielding Effectiveness Calculator
Electromagnetic Shielding Effectiveness Calculator computes SE in dB for a conductive shield using conductivity, permeability, thickness, and frequency.
Formulas Used in Electromagnetic Shielding Effectiveness Calculator
The calculator computes the shielding effectiveness (SE) in decibels (dB) as the sum of absorption loss (\\(A\\)), reflection loss (\\(R\\)), and multiple reflection correction (\\(B\\)):
Total Shielding Effectiveness:
\\[ \text{SE} = A + R + B \\]Absorption Loss:
\\[ A = 131.4 \, t \sqrt{f \mu_r \sigma} \\]Reflection Loss (Far Field, Plane Wave):
\\[ R = 168 – 10 \log_{10} \left( \frac{f \mu_r}{\sigma} \right) \\]Multiple Reflection Correction:
\\[ B = 20 \log_{10} \left( 1 – e^{-2t / \delta} \right) \\]Skin Depth:
\\[ \delta = \frac{1}{\sqrt{\pi f \mu_0 \mu_r \sigma}} \\]Where:
- \\( \text{SE} \\): Shielding effectiveness (dB)
- \\( A \\): Absorption loss (dB)
- \\( R \\): Reflection loss (dB)
- \\( B \\): Multiple reflection correction (dB, typically negligible for thick shields or high frequencies)
- \\( \sigma \\): Conductivity of the shield material (S/m)
- \\( \mu_r \\): Relative permeability of the material
- \\( \mu_0 \\): Permeability of free space (\\( 4\pi \times 10^{-7} \, \text{H/m} \\))
- \\( t \\): Shield thickness (m)
- \\( f \\): Frequency of the electromagnetic wave (Hz)
- \\( \delta \\): Skin depth (m)
Example Calculations
Example: Copper shield with \\( \sigma = 5.96 \times 10^7 \, \text{S/m}, \mu_r = 1.0, t = 0.001 \, \text{m}, f = 1 \times 10^6 \, \text{Hz} \\)
Result: \\( \text{SE} \approx 251.19 \, \text{dB}, A \approx 101.43 \, \text{dB}, R \approx 149.77 \, \text{dB}, B \approx -0.01 \, \text{dB}, \delta \approx 0.0652 \, \text{mm} \\)