Mobile phones are wireless communications devices that use frequencies in the microwave band.
Microwave energy can be absorbed by water and converted to heat energy. There is growing concern, especially in Europe, about the potential for harm arising out of the effects of the absorbtion of mobile phone microwave radiation in the brain of the user. In particular, both the use of unidirectional aerials and their very close proximity with the cranium have been identified as special risks. However, some current research suggests these standards may be inadequate and incomplete.