Microwave cookers work with high local radiation levels at a frequency carefully tuned to the resonant frequency of water molecules, and it is reflected back from the cooker metal lining until it is absorbed by the contents. The radiation will not travel far through anything that contains water molecules, so the middle of a large item only receives heat energy by conduction and will only cook slowly. Radiated power at that frequency will be absorbed by any water molecules, including that in the atmosphere, so it is useless for communications.The frequencies used for mobile phones may be fairly close, so there has been a lot of testing. The radiation level will be much lower, and it will only travel a very short distance after passing through the skin, so there may be very slight local heating, but there has not been any other effect found. It is classed as non-ionizing radiation, and the power levels used are selected to travel relatively short distances so as to avoid interference with transmissions in other areas.
Chris Bell ● 5371d