Active Denial System

Active Denial System (ADS) / Heat Ray

Active Denial System (ADS) or Heat Ray is a directed energy weapons in development, which uses a millimetre wave beam to heat the skin and cause a painful burning sensation. The weapon, developed by the US military is non-lethal and is designed for area denial, perimeter security and crowd control. Informally, the weapon is also called the heat ray, since it works by heating the surface of targets, such as the skin of targeted human subjects. In 2010, US military had deployed the ADS in Afghanistan War. ADS is currently only a vehicle-mounted weapon, though U.S. Marines and police are both working on portable versions.

How does it work?

ADS works by firing a high-powered beam of 95 GHz extremely high frequency waves at a target, which corresponds to a wavelength of 3.2 mm (thus called millimeter wave). The ADS millimeter wave energy works on a similar principle as a microwave oven, exciting the water and fat molecules in the skin, and instantly heating them via dielectric heating. However, microwave oven uses the much lower frequency (and longer wavelength) of 2.45 GHz. The short millimeter waves used in ADS only penetrate the top layers of skin, with most of the energy being absorbed within 0.4 mm (1/64"), whereas microwaves will penetrate into human tissue about 17mm (0.67")