What is the function of the capacitor in a refrigerator?

The term Microwave is a description of a high frequency radio wave in the range of 1 Gigahertz (One million cycles per second) to 40 gigahertz (40 million cycles per second). Radio waves at this frequency have the tenancy to reflect & refract making them useful for a wide number of applications.

Also since the radio wavelength is related to the frequency (frequency in Hertz divided by the speed of light in metres per second equals wavelength) the aerial size for this band is very small allowing for the use of exotic aerial systems such as dishes.

Dish aerials (antenna) are extremely efficient reflectors for microwave transmitters producing point to point links which can operate over many miles. Unlike High low and medium frequency Transmitters, microwave frequencies are not affected by the ionisation of the gas layers in the atmosphere. Therefore they tend to pass straight through the atmosphere rather than being reflected or refracted back to Earth. This makes them very useful for space communications and radio astronomy.

Microwaves do have some problems though. It is relatively expensive to generate high output at microwave frequencies. Also the nature of microwaves is that they do not pass through solid or grounded objects. This means that rain clouds can block the signal. Also at high power, microwaves excite water molecules, causing them to heat up (this is the principle of the microwave oven). Therefore inappropriate use can be hazardous to health.

Microwave are used to locate ships and planes, track weather systems, and determine the speeds of moving objects. They are the principal carriers of television, telephone, and data transmissions between stations on Earth and between the Earth and satellites.