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A novel security scanner that individuals can easily pass by might soon be arriving at an airport close to you. Last year, airports across the U.S. began integrating HEXWAVE — a commercialized walkthrough security screening system rooted in microwave imaging technology created at MIT Lincoln Laboratory — to comply with a fresh Transportation Security Administration (TSA) requirement for improved employee screening aimed at identifying metallic and nonmetallic threats. The TSA is currently assessing HEXWAVE as a possible substitute for metal detectors for screening PreCheck travelers.
Generally, upon reaching an airport security checkpoint line, you place your carry-on belongings on the conveyor belt, take off your shoes and any metallic objects, and step into a body scanner. While you remain still for a few seconds with your feet apart and arms raised above your head, the scanner generates a basic, featureless 3D outline of your body, revealing any concealed weapons or other forbidden items.
Asking individuals to halt, remove garments and possessions, and pose for scans disrupts the flow of traffic in airports and other crowded locations, such as stadiums, shopping centers, mass transit hubs, and educational institutions. To enable more effective screening of unstructured crowds and ensure public safety, the Department of Homeland Security (DHS) Science and Technology Directorate (S&T) funded Lincoln Laboratory to develop a high-resolution imaging system capable of scanning people and their belongings as they pass. This research and development initiative was part of S&T’s Surface Transportation Explosive Threat Detection Program, which aims to equip the surface-transportation community (e.g., mass transit) with a layered and integrated solution to identify threat items at the pace of the traveling public.
The laboratory’s microwave imager prototype, which is made up of a series of antennas mounted on flat panels, operates under the same fundamental principle as current body scanners: low-energy radio waves (less potent than those emitted by a cell phone) are sent from antennas towards a person’s body and bounce off their skin and any concealed objects. The returning waves are captured by the antennas and processed by a computer to generate an image, which security personnel review to recognize possible concealed threats.
The uniqueness of the laboratory’s invention lies in its ability to discreetly manage a continuous stream of moving subjects, measuring each one rapidly (within tens of milliseconds) and reconstructing 3D microwave images at a video-like rate. To meet these demanding specifications, the laboratory team developed a cost-effective antenna array and efficient image-reconstruction algorithms. When compared to existing systems, the laboratory’s 3D microwave imager operates 100 times faster using the same computational hardware. In 2017, the team showcased the prototype’s capability to detect various simulated threat items at varying distances on a rail platform at the Massachusetts Bay Transit Authority (MBTA) Emergency Training Center in Boston.
“The aim of our endeavor is to equip security personnel with more efficient tools to safeguard public areas. Accordingly, microwave imaging technology can swiftly and unobtrusively provide insight into items brought into a location,” states William Moulder, who spearheaded the technology’s development at Lincoln Laboratory.
In 2018, the security firm Liberty Defense obtained a license for the imaging technology and entered into a cooperative research and development agreement (CRADA) with Lincoln Laboratory. Transitioning technology to the industry for commercialization forms part of the laboratory’s role as a federally supported research and development center, and CRADAs provide a framework for such transitions. Through the CRADA, Liberty Defense preserved Lincoln Laboratory’s core image-reconstruction intellectual property and implemented the technological enhancements necessary for commercialization, including a completely new hardware framework, radio frequency (RF) antenna modules, and a transceiver system that complies with Federal Communications Commission waveform and RF performance criteria for indoor and outdoor usage. The collaborative team facilitating the technology’s transition was honored by the Federal Laboratory Consortium for Technology Transfer with a 2019 Excellence in Technology Transfer Award for the Northeast region.
By 2021, Liberty Defense had developed a walkthrough security screening system, HEXWAVE. That same year, through the TSA’s On-Person Screening Capability Program, Liberty Defense secured a contract to showcase HEXWAVE’s advanced threat-detection and high-throughput capabilities for screening aviation personnel. After successful trials of HEXWAVE at sports venues, entertainment arenas, and shopping centers, both domestically and internationally, Liberty Defense commenced offering the product for sale.
“HEXWAVE exemplifies how federally funded research and development can be effectively transitioned to industry to fulfill genuine security demands,” remarks Asha Rajagopal, the laboratory’s chief technology transfer officer. “By collaborating with Liberty Defense, we expedited the delivery of a vital capability to those safeguarding public spaces.”
In 2023, TSA initiated testing for HEXWAVE as a possible replacement for metal detectors employed in TSA PreCheck lanes. Airports nationwide commenced implementing HEXWAVE in 2024 to fulfill TSA’s employee screening directive by the April 2026 deadline. Liberty Defense highlights various additional markets for HEXWAVE; the initial units for commercial use were supplied to Los Alamos National Laboratory in 2023, and the technology has subsequently been deployed at other national laboratories, correctional institutions, government facilities, and courthouses.
“Liberty was incredibly fortunate to license the technology from MIT Lincoln Laboratory,” expresses Bill Frain, CEO of Liberty Defense. “From the beginning, they’ve been an authentic partner — providing not only profound innovation and technical know-how but also a clear vision for commercialization. Together, we’ve effectively brought next-generation technology to market to help ensure the safety of individuals in public areas.”
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