Radar is a radio wave sent from a radar transmitter. The radio wave hits a moving vehicle, then is bounced back to the receiver. The radar measures the time the radio wave takes to go from the police vehicle to the target and back. The transmitter then calculates the time giving a speed. Distance / Time = Speed
As radar is a radio wave, the radar beam travels at the speed of light.
A Radar Transmitter is a device that oscillates an electrical current so the voltage goes up and down at a certain frequency.
This electricity generates electromagnetic energy and when the current is oscillated the energy travels thought the air as an electromagnetic wave.
A transmitter also has an amplifier that increases the intensity of the electromagnetic energy and an antenna that broadcasts it into the air..
Basically the transmitter sends out the radar wave which strikes the moving vehicle. The radar receiver is just the reverse of the transmitter. The receiver picks up electromagnetic waves with an antenna and converts them back into an electrical current. A radio wave is the transmission of electromagnetic waves through space..
Radar is the use of radio waves to detect and monitor various objects. The simplest function of radar is to tell you how far away an object is (distance).
To do this the radar device emits a concentrated radio wave and listens for an echo or signal back..
If there is an object in the path of the radio wave like a speeding car, it will reflect some of the electromagnetic energy and the radio wave will bounce back to the radar device.