Wikipedia: Induction Cooking
Fields or Waves?
This causes a lot of confusion, so we need to touch upon this briefly here before
carrying on. It will also help distinguish between MPT and inductive WPT. The
electromagnetic spectrum is shown in Figure 2. We can observe the frequencies used for MPT (2.45GHz) and also for modern inductive WPT (~100-350 kHz and 6.78 MHz).
The first thing we realize is the frequency for MPT is much higher than inductive WPT. But the high-frequency aspect of MPT itself is not the real problem per se. After all, visible light has even higher frequencies and it is safe. The effect of MPT is more related to certain biological effects at certain frequencies. For that reason, mobile devices are routinely tested for compliance to mandatory SAR emission limits over the range 30 MHz to 6 GHz as shown. Not against visible light obviously!
There is another concept we need to understand: far-fields and near-fields. Time-varying magnetic fields induce electric fields, and similarly, as Maxwell showed in 1865 by extending Faraday’s Law, time-varying electric fields generate magnetic fields. There is a certain duality between them. Further, as we go further from the magnetic or electric source, the electric and magnetic fields tend to become more and more tangential to