Researchers from Rutgers University demonstrated the readily available WiFi signals from low-cost devices can penetrate into baggage without any dedicated devices or signals. The system only requires a WiFi device with 2 to 3 antennas and can be integrated into existing WiFi networks with low costs and deployment efforts, making it more scalable and practical than the approaches using dedicated instruments. Researchers evaluated 15 metal and liquid objects and 6 types of bags in a 6-month period. They said that Our system can be easily deployed to many places that still have no pre-installed security check infrastructures and require high-manpower to conduct security checks.”]
Source: https://gbhackers.com/wi-fi-devices-weapons-and-bombs/