These fields are all used to send information over long distances. They are the basis for telecommunications in general. They serve radio and television broadcasts around the world. In microwave ovens, they get the food reheated very fast.
At radio frequencies and microwaves, the electric and magnetic fields are interdependent. They constitute the two main components of the electromagnetic field. The latter propagates in the form of an electromagnetic wave. The intensity of this field is now measured by power density.