# How much does human tissue attenuate radio frequency signal of a given frequency?

Attenuation of radio frequency (rf) signals in a medium depends upon medium characteristics and frequency of the signal. How much does human tissue attenuate rf signal of a given frequency?

• Didn't the Italian courts just make a ruling about this topic re mobile phones? Apr 22 '17 at 12:20

## 1 Answer

The intensity $I_0$ of an electromagnetic wave gets attenuated to the intensity $I$. The law describing the relationship between $I_0$ and $I$ is given by the Beer–Lambert law.

$$I(d) = I_0\exp(-\alpha d)$$

The depth of penetration is given by $d$ and $\alpha$ is the coefficient of absorbance(must be given, e.g. this publication).

Intensity $I$ is linked to the maximal amplitude of the electric field $E_0$ or the maximal aplitude of the magnetic field by:

$$I=\frac{c\varepsilon_0}{2}E_{0}^{2}=\frac {c}{2\mu_{0}}B_{0}^{2}.$$

The speed of light is represented by $c$. The Greek letters $\varepsilon_0$ and $\mu_0$ are the vacuum permittivity and vacuum permeability.