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 a frequency of 10-20 GHz is classified as a microwave detector. This classification is based on the technology it employs to detect motion. Microwave detectors use high-frequency electromagnetic waves to sense changes in the environment, specifically the movement of objects.

When an object, such as a person, moves through the field of the emitted microwave signals, it reflects the signals back to the detector. The detector analyzes these reflections and determines if there is motion based on variations in the returned signals. This technology is effective for covering larger areas and can detect movement through barriers such as walls, unlike other types of detectors.

In contrast, imaging detectors primarily capture two-dimensional images and are not focused on motion detection in the same way. PIR (Passive Infrared) detectors, on the other hand, work by sensing changes in infrared radiation, which is emitted by warm bodies. Ultrasonic detectors use sound waves at a frequency above the human hearing range to detect motion by measuring changes in the reflected sound waves. Therefore, the distinction between these technologies helps clarify why a detector working at the frequencies mentioned is categorized specifically as a microwave detector.