Equalization for antenna-pattern measurements: established technique - new application

This paper describes a novel system that overcomes the inaccuracies in antenna radiation-pattern measurements caused by multipath propagation. The system operates by specifically correcting for the effects of unwanted signals, rather than by attempting to remove, or minimize, them through the use of screens, or baffles, or an anechoic chamber. An equalization technique is used, the parameters of the equalizer(s) being determined from a special measurement of the antenna range under consideration. The method is generally applicable; it may be implemented ab initio in new indoor or outdoor ranges, or retrofitted to existing ranges to improve accuracy. Most importantly, however, the basic idea leads to the design of a completely new type of real-time three-dimensional range, in which sensors are placed on the surface of an imaginary sphere surrounding the antenna under test (AUT), and an anechoic chamber is not required.