If you’ve traveled by plane in recent years, you know the airport security drill: Put all your possessions through the X-ray detector, empty your pockets and step into one of the full-body scanners — or millimeter-wave holographic scanner, to use its official name. After you raise your hands above your head, the scanner sends out millimeter waves (mm-waves) that penetrate your clothing and bounce off your skin — or any other object you might be trying to conceal under your clothing, like a weapon of some sort. (The mm-wave radiation is 10,000 times less powerful than a single cellphone call, so you need not be concerned about any health effects.) An antenna array in the sweeping scanner device detects the reflected mm-waves and reconstructs an image of your body.
Airport mm-wave scanner
Security personnel see only a generic 3D human form on their screen; any suspicious area detected by the scanner is highlighted. It may be just a stray coin left in your pocket, or a piece of paper, but if the scanner detects anything you then have to undergo an additional wand search by security personnel.
Though it’s a step most of us would like to skip, if only for the extra time it takes, mm-wave full body scanning increases our confidence that we are boarding a safe airplane, and that none of our fellow passengers is carrying a weapon. Enhanced airport security is necessary in today’s troubled world.
We can thank the engineers of the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, for the mm-wave scanner, which they developed and tested in the field in 2003. They licensed and the sold the technology to commercial enterprises in 2006.
But PNNL engineers never stopped working on improving the full-body scanner. Unlike the first time around, when they used a mannequin coated with reflective paint and a standard laboratory scanner to test physical prototypes, they now have ANSYS engineering simulation solutions to improve the design virtually. Simulation enables engineers and designers to develop and test devices more thoroughly and quickly than was ever possible using physical prototypes, so new products can get to market sooner.
With ANSYS HFSS SBR+ technology to simulate the antennas, PNNL engineers have been able to study the effects of the mm-wave bandwidth (the span in GHz), beamwidth (the angular coverage) and polarization (cross-circular versus vertical polarization) on the quality and resolution of the 3D holographic images they obtained from the full-body scanner.
PNNL researchers varied bandwidth and beamwidth
to determine the best-quality image.
To speed up the design and testing process, they coupled the simulation software with high-performance computing to run 10 simulations simultaneously. The engineers obtained realistic simulated image datasets in less than a day.
To learn more about the details of how PNNL engineers used ANSYS technology to detect concealed weapons with even greater accuracy while reducing false alarms, read the article in the latest issue of ANSYS Advantage magazine.
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