MrSeb writes "Up there with invisibility, teleportation, and being able to cancel mid-season TV breaks, x-ray vision is one of the most sought after superpowers — and that seems to be what a couple of researchers from MIT have managed to do. It isn’t quite x-ray vision — it uses microwaves instead — but MIT’s radar array, made by Gregory Charvat and John Peabody, can see through 8-inch concrete walls. Basically, it works just like a normal radar system: 44 antennae send out S-band microwaves (2-4GHz, about 10cm peak to peak). Most of these microwaves — 99.4% — bounce off the solid concrete wall. The 0.6% that make it through bounce off any objects on the other side, and then come back through the wall, losing another 99.4% of the waves. By the time the microwaves return to the array, the signal is just 0.0025% of its original strength. The reflected waves are then amplified, subtracted from the concrete wall's echo using an analog crystal filter, and then converted into moving blobs by a computer. The entire rig is about 8 feet wide, and it is designed to be mounted on a military truck for urban warfare — but it could revolutionize emergency response, too, with the ability to see through rubble and collapsed buildings for survivors."
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