The ADS works by directing electromagnetic radiation at a frequency of 95 GHz toward the subjects. The waves excite (see Excited state) water molecules in the epidermis (skin) to around 55 C (130 degrees Fahrenheit), causing an intensely painful burning sensation. While not actually burning the skin, the burning sensation is similar to that of a light bulb being pressed against the skin. The focused beam can be directed at targets at a range of approximately one kilometer.
A higher radio frequency is chosen because, as a property of electromagnetic waves (known as "skin depth"), they are unable to penetrate the body as deeply as lower frequency waves, thereby affecting external organs only, such as skin. The United States military states the effect "penetrates the skin to a depth of less than 1/64 of an inch." A spokesman for the Air Force Research Laboratory described his experience as a test subject for the system: "For the first millisecond, it just felt like the skin was warming up. Then it got warmer and warmer and you felt like it was on fire.... As soon as you're away from that beam your skin returns to normal and there is no pain."
The ADS is currently only a vehicle mounted weapon, however, U.S. Marines and police are both working on portable versions.
A fully operational and mounted system was demonstrated Wednesday, Jan. 24, 2007, at Moody Air Force Base, Ga.