We have all heard of the term 'radar' but we rarely ask ourselves what radar really means? What are its uses? And what is the purpose of it? Radar is a short form for 'radio detection and ranging'. It is a remote detection process which is used to trace and identify objects. Radar can determine the distance, speed, direction of motion and shape of an object. The radar can identify objects even if it is out of sight. It can also work in all kinds of weather conditions which made this an essential tool for many industries. This device is used in navigation in the sea and air, helps in detecting military forces and also helps improve traffic safety. Radar has also become a very important tool for every policeman because they can easily catch a speeding motorist by only using radar detector. But how do these radar detectors work? In order to work the radar system is composed of four very important components. These are the transmitter, the antenna, the receiver, and the display. • The transmitter produces electrical signals in the correct form for the type of radar system. • The antenna on the other hand, sends these signals out as electromagnetic radiation. The antenna also collects incoming return signals and passes them to the receiver. • The receiver analyzes the signals and passes it to the display. • The display allows human operators to see the signal data. Radar depends on sending and receiving electromagnetic radiation which is regularly in the form of radio waves or microwaves. Electromagnetic radiation is energy that moves in waves at or close to the speed of light. The characteristics of electromagnetic waves depend on their wavelength. Gamma rays and X rays have very short wavelengths. Noticeable light is a tiny slice of the electromagnetic spectrum with wavelengths longer than X rays, but shorter than microwaves. Radar systems use long-wavelength electromagnetic radiation in the microwave and radio ranges. Because of these long wavelengths, radio waves and microwaves are inclined to reflect better than shorter wavelength radiation, which tends to scatter or be absorbed before it gets to the target. Radio waves at the long-wavelength end of the spectrum will even reflect off of the atmosphere’s ionosphere, a layer of electrically-charged particles in the earth’s atmosphere. Radar usually starts it system by sending out signals. The signal bounces off a target object and returns to the radar gun. This signal moves at a steady speed of light, so a computer unit can determine the time it takes for a signal to return. If the target object is moving towards the radar gun, the frequency becomes higher due to a phenomenon called the Doppler shift. This means a moving police vehicle can exactly estimate the speed of a car approaching it. Police do not have to remain still by the side of the highway to detect speeders with radar guns. Radar detectors are small devices used by many drivers to identify the presence of radar police units. These radar detectors will pick up the radar gun’s signal before the driver speeds his/her vehicle past the police using it.