title: Simulation and Measurement of Medium-Frequency Signals Coupling From a Line to a Loop Antenna.
abstract: The underground-mining environment can affect radio-signal propagation in various ways. Understanding these effects is especially critical in evaluating communications systems used during normal mining operations and during mine emergencies. One of these types of communications systems relies on medium-frequency (MF) radio frequencies. This paper presents the simulation and measurement results of recent National Institute for Occupational Safety and Health (NIOSH) research aimed at investigating MF coupling between a transmission line (TL) and a loop antenna in an underground coal mine. Two different types of measurements were completed: 1) line-current distribution and 2) line-to-antenna coupling. Measurements were taken underground in an experimental coal mine and on a specially designed surface test area. The results of these tests are characterized by current along a TL and voltage induced in the loop from a line. This paper concludes with a discussion of issues for MF TLs. These include electromagnetic fields at the ends of the TL, connection of the ends of the TL, the effect of other conductors underground, and the proximity of coal or earth. These results could help operators by providing examples of these challenges that may be experienced underground and a method by which to measure voltage induced by a line.
authors: Office of Mine Safety and Health, National Institute for Occupational Safety and Health, Pittsburgh, PA 15236 USA.
authors: Nicholas W
authors: NW
authors: Damiano
authors: Office of Mine Safety and Health, National Institute for Occupational Safety and Health, Pittsburgh, PA 15236 USA.
authors: Jingcheng
authors: J
authors: Li
authors: Office of Mine Safety and Health, National Institute for Occupational Safety and Health, Pittsburgh, PA 15236 USA.
authors: Chenming
authors: C
authors: Zhou
authors: Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 USA.
authors: Donovan E
authors: DE
authors: Brocker
authors: Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 USA.
authors: Yifeng
authors: Y
authors: Qin
authors: Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 USA.
authors: Douglas H
authors: DH
authors: Werner
authors: Department of Electrical Engineering, The Pennsylvania State University, University Park, PA 16802 USA.
authors: Pingjuan L
authors: PL
authors: Werner
keywords: Medium-frequency (MF) communications; parasitic coupling; transmission line (TL)