Common everyday applications of microwaves include garage door openers, keyless entry systems, and of course, microwave ovens! A microwave oven works by passing microwave radiation through the food, usually at a frequency of 2.45 GHz (a wavelength of 12.24 cm).
More advanced applications include medical cauterization, radar, and satellite communications. Microwaves are particularly good at penetrating haze, light rain and snow, clouds, and smoke, and are thus utilized in satellite weather forecasting.
Antennae
The radio and micro wave portion of the EM spectrum is the mechanism used to send data. But the data still needs to come from somewhere (transmit) and go somewhere (receive) for it to be useful. Artificially generated radio waves require antennae (aka aerials: rods or dishes) that transmit, receive, and respectively convert electrical signals into waves and waves into electrical signals.
1) Electricity flowing into the transmitter antenna makes electrons vibrate up and down , producing radio waves.
2) The radio waves travel through the air at the speed of light.
3) When the waves arrive at the receiver antenna, they make the electrons inside vibrate This produces an electric current that recreates the original signal.
Waves do not simply zap through the air from transmitter to receiver. Depending on what kinds of waves we want to send, how far we want to send them, and when we want to send them, there are actually three different ways in which the waves can travel:
1. They can shoot by what is called "line of sight", in a straight line - just like a beam of light. Prior to cellular and fibre-optic technology, this is how long distance telephone communication occurred.
2. They can speed around the Earth's curvature in what is known as a ground wave. AM radio tends to travel this way for short to moderate distances.
3. Like a sort of "sky mirror", they can shoot up to the sky, bounce off the ionosphere (an electrically charged part of Earth's upper atmosphere), and come back down to the ground again.