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Attenuation constants of radio waves in lossy-walled rectangular waveguides.

Authors
Zhou-C; Waynert-J; Plass-T; Jacksha-R
Source
Prog Electromagn Res 2013 Aug; 142:75-105
NIOSHTIC No.
20043133
Abstract
At the ultra-high frequencies (UHF) common to portable radios, the mine tunnel acts as a dielectric waveguide, directing and absorbing energy as a radio signal propagates. Understanding radio propagation behavior in a dielectric waveguide is critical for designing reliable, optimized communication systems in an underground mine. One of the major parameters used to predict the power attenuation in lossy waveguides is the attenuation constant. In this paper, we theoretically and experimentally investigate the attenuation constants for a rectangular waveguide with dielectric walls. We provide a new derivation of the attenuation constant based on the classic Fresnel reflection coefficients. The new derivation takes advantage of ray representation of plane waves and provides more insight into understanding radio attenuation in tunnels. We also investigate the impact of different parameters on the attenuation constant, including the tunnel transverse dimensions, permittivity, conductivity, frequency, and polarization, with an aim to find their theoretical optimal values that result in the minimum power loss. Additionally, measurements of the attenuation constants of the dominant mode at different frequencies (455, 915, 2450, and 5800 MHz) for a straight concrete tunnel are presented and compared to theoretical predictions. It is shown that the analytical results match the measured results very well at all four frequencies.
Keywords
Radio-waves; Underground-mining; Wave-propagation; Communication-systems; Audiofrequency; Sound-attenuation; Sound-propagation
Contact
Chenming Zhou, National Institute for Occupational Safety and Health, Pittsburgh, PA 15236
CODEN
PELREX
Publication Date
20130806
Document Type
Journal Article
Email Address
czhou@cdc.gov
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Identifying No.
M102013
ISSN
1559-8985
NIOSH Division
OMSHR
Priority Area
Mining
Source Name
Progress in Electromagnetics Research
State
PA
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