EMF unit converter
Within a quantity the factors are exact. Between electric field strength and power density they are not: that relation holds only in the far field, and never for a transmitter against the body.
0.4 T = 400 mT
0.4 T × 1 / 0.001 = value in mT
Cross-quantity relations
- Electric field strength → power density (far field)
- S = E² / 376.730 Ω — 6 V/m = 95,559 µW/m². Valid in the far field only, roughly beyond one wavelength from the source. Not applicable to near-field exposure such as a handset against the head, which is assessed as SAR.
- Power density → electric field strength (far field)
- E = √(S × 376.730 Ω) — 0.1 W/m² = 6.14 V/m. Far field only; the fixed E/H ratio this assumes does not hold within about one wavelength of an antenna.
- dBm → watts
- P(W) = 10^(dBm/10) / 1000 — 20 dBm = 0.1 W, and dBm = 10 · log₁₀(P(W) × 1000) gives 0.1 W = 20 dBm.
- Magnetic flux density → magnetic field strength
- H = B / µ₀ in air. 1 µT ≈ 0.796 A/m. Regulatory reference levels below 100 kHz are usually written in µT rather than A/m, so conversion is rarely needed.
JSON: /api/convert