Microwave motion sensors for automatic doors work by the doppler-shift principle. The sensor sends out electromagnetic waves at a specific frequency. When these waves hits a moving object, they reflect back to the detector. The system compares the frequency of the transmitted waves with the reflected waves. Any difference in frequency (Doppler shift) indicates movement, allowing the system to detect objects and their motion.
Types of Waves Analyzed by the Sensor
Normal Wave
When there are no moving objects in the path, the reflected waves return unchanged.
Altered Wave
If a moving object is detected, the reflected waves are altered.
Result
The altered waves change the echo time, triggering the connected door controller which accordingly opens or closes the door depending on the settings.
Highly Sensitive
Detects even slight movements.
Wide Range Detection
Covers a large area.
Improved Accuracy
Reliable in various conditions.
Penetrates Obstacles
Can detect through glass, plastic, and thin walls.