A real-time location system using near-field electromagnetic ranging

Near-field electromagnetic ranging (NFER) technology is emerging as a preferred real-time locating system (RTLS) solution for operation in complicated indoor propagation environments [H. Schantz and R. DePierre, 2005]. Operating at low frequencies, typically within the AM broadcast band (530-1710kHz), NFER systems exploit the near-field behavior of radio signals within about one-third of a wavelength. This paper explores the performance of NFER systems and the propagation of NFER signals.