- Sensitivity: mmWave sensors are more sensitive than PIR sensors, and can detect even the slightest movements, like breathing or heart rate.  - Range: PIR sensors typically have a range of about 30 feet, but more advanced models can have a range of up to 100 feet.  - Cost: PIR sensors are generally cheaper than mmWave sensors.  - Form factor: PIR sensors have a different form factor than mmWave radar sensors.  - Accuracy: mmWave sensors are more accurate due to their short wavelengths - False alarms: PIR sensors can sometimes trigger false alarms, and their short detection range can lead to incomplete coverage