A motion detector that functions at a frequency of 10-20 GHz is classified as which type of detector?

A motion detector that operates at frequencies between 10-20 GHz is classified as a microwave detector. These detectors utilize microwave signals to detect motion within their field of coverage. When an object moves within the beam of microwaves emitted by the detector, it causes a change in the frequency of the reflected signals due to the Doppler effect, which the detector interprets as motion.

Microwave detectors are particularly effective in detecting motion through barriers and can cover larger areas compared to other types of motion detectors, such as PIR (Passive Infrared) detectors, which rely on detecting changes in infrared radiation or heat signatures. Ultrasonic detectors use sound waves at frequencies above the range of human hearing to detect changes in the environment. Imaging detectors, on the other hand, create a visual representation of a scene and do not primarily function through microwave technology, making them unrelated to the frequency specified in the question. Thus, the classification of a motion detector operating within the 10-20 GHz range as a microwave detector is accurate and based on the principles of how these devices function.