This calculator estimates the power absorbed by a fabric and the incident power density from the electric field, conductivity and density of the material, to assess electromagnetic exposure and compliance with safety limits.
Formulas
SAR = (σ × E²) / md
Incident power density = E² / 377
Explanation
- σ is the conductivity of the material in siemens per meter (S/m).
- E is the magnitude of the electric field in volts per meter (V/m).
- md is the density of the material in kilograms per cubic meter (kg/m³).
- The constant 377 represents the vacuum impedance in ohms and converts the square of the electric field to power density.
- The SAR obtained is expressed in watts per kilogram (W/kg) and the power density in watts per square meter (W/m²).
Uses
- Assessment of human exposure to RF fields for regulatory compliance.
- Absorption studies in biological tissues and dielectric materials.
- Design and testing of wireless devices to limit the impact on health.
- Validation tools for electromagnetic compatibility laboratories and engineers.