Near-Field Antenna Measurements facility

At Fort Huachuca, Ariz., the U.S. Army constructed a compact radar range thought to be the world's largest.

To determine the best antenna location for a particular situation, Dr. R.C. Johnson of the Engineering Experiment Stations (now Georgia Tech Research Institute, GTRI) invented the compact radar range in the late 1960s. The technique simulates a plane wave over the entire antenna under testing and involves two main elements: a parabolic reflector and a mechanical device that lifts and rotates the target antenna.

Although the compact range operates in a relatively small space — most are indoors — it can measure the radiation patterns of antennas as they would occur over long distances. Advantages of indoor compact ranges are security and the ability to operate regardless of weather conditions.