With further technology development, radar becomes more and more attractive for touchless devices. Radar sends electromagnetic waves which travel by the speed of light and are imperceptible by humans. These waves will bounce on objects on their way, and part of the energy will be reflected back to the radar as an echo. The signal is received by the radar antenna and will be recognized by the sensor; the echo will then be evaluated by signal processing. In this way, the engineer can use the given data to locate the object and output an impulse. Radar can precisely measure movement, presence, velocity, direction, distance, and angle of various objects.