A new generation of security screening systems is being deployed in airports across the United States, promising to enhance safety while reducing the hassle and wait times for travelers. These walkthrough systems, based on advanced imaging technology, can detect metallic and nonmetallic threats without requiring passengers to stop, remove clothing, or empty their pockets. The technology, which was originally developed at MIT Lincoln Laboratory, is now being commercialized and adopted by the Transportation Security Administration (T.S.A.) to meet new mandates for employee screening, and it is also being evaluated for use in passenger lanes.
The new screeners are designed to address the bottlenecks and inefficiencies of traditional security checkpoints, which can be a major source of frustration for travelers and a challenge for airport operators. By allowing a continuous flow of people, the walkthrough systems can significantly increase throughput and create a more seamless and less intrusive screening experience. The technology is also being implemented in a variety of other high-security environments, including national laboratories, government buildings, and correctional facilities, demonstrating its versatility and effectiveness.
Advanced Imaging Technology
Microwave and Millimeter-Wave Scanning
The core of these new screening systems is advanced imaging technology that uses low-energy radio waves to detect concealed objects. Two of the leading technologies are microwave imaging and millimeter-wave scanning. The HEXWAVE system, for example, is based on microwave imaging technology developed at MIT Lincoln Laboratory. It works by transmitting radio waves that are less powerful than those from a cellphone toward a person’s body. These waves reflect off the skin and any hidden objects, and the reflected waves are then used to create a 3D image that can be analyzed for potential threats.
Another system, the QPS Walk2000, employs millimeter-wave scanners. This technology has been successfully implemented at Frankfurt Airport, the first in the world to use such a system on a large scale. Both microwave and millimeter-wave technologies are capable of detecting a wide range of threats, including both metallic and nonmetallic items, which is a significant advantage over traditional metal detectors.
Real-Time Imaging and Artificial Intelligence
A key innovation in these systems is their ability to capture and process images in real time, even as people are in motion. The MIT Lincoln Laboratory’s prototype, for example, can reconstruct 3D microwave images at a video rate, making it 100 times faster than previous systems using the same computing hardware. This high-speed processing is essential for enabling a continuous flow of people through the screening area.
NEC’s Invisible Sensing (IVS) system is another example of a walkthrough scanner that utilizes microwave radar and artificial intelligence to detect weapons in real time. The IVS system can distinguish between dangerous objects and everyday items, which helps to reduce the number of false alarms. By using AI-driven detection engines, these systems can achieve high levels of accuracy while maintaining a high throughput of passengers.
Implementation in U.S. Airports
T.S.A. Mandates and Adoption
The adoption of walkthrough screening systems in U.S. airports has been driven in part by a new T.S.A. mandate for enhanced employee screening. The mandate requires the detection of both metallic and nonmetallic threats, a capability that the new generation of scanners provides. As a result, airports across the country began deploying the HEXWAVE system in 2024 to meet the April 2026 deadline.
The T.S.A. is also evaluating the HEXWAVE system as a potential replacement for metal detectors in its PreCheck lanes. This move could bring the benefits of faster, more convenient screening to a wider range of travelers. The Department of Homeland Security’s Science and Technology Directorate sponsored the initial research and development of the technology, with the goal of providing a more effective and efficient way to screen large crowds in public spaces.
Improving the Passenger Experience
Beyond the security benefits, walkthrough screening systems offer a significant improvement in the passenger experience. The ability to walk through a scanner without stopping or removing personal items reduces stress and frustration for travelers. Sascha König, an official at Frankfurt Airport, noted that the QPS Walk2000 system provides “significantly greater comfort and convenience” for passengers. By creating a smoother and more efficient screening process, airports can improve customer satisfaction and overall operational efficiency.
Global Applications and Future Developments
International Adoption
The use of walkthrough screening technology is not limited to the United States. Frankfurt Airport’s successful implementation of the QPS Walk2000 system is a testament to the global interest in this technology. The airport is now looking to install the newest scanners available on the market in its new Terminal 3, with the goal of creating a centralized security checkpoint with remote screening capabilities.
NEC’s Invisible Sensing system is also being considered for use in other parts of the world, such as the Philippines, to address security concerns in its urban railway systems. The high throughput and user convenience of these systems make them an attractive solution for a wide range of security challenges in public transportation and other crowded venues.
Ongoing Research and Development
The development of walkthrough screening technology is an ongoing process, with researchers continuously working to improve its capabilities. The transition of the microwave imaging technology from MIT Lincoln Laboratory to the commercial sector through a cooperative research and development agreement with Liberty Defense is a successful example of how federally funded R&D can be brought to market to meet real-world needs. As the technology continues to evolve, we can expect to see even more advanced and effective screening solutions in the future. These advancements will likely focus on further improving detection accuracy, reducing false alarm rates, and enhancing the ability to distinguish between a wider variety of objects.
