Modeling RF propagation in tunnels

Zhou, Chenming; Waynert, J. A.; Plass, Timothy; Jacksha, Ronald

doi:10.1109/aps.2013.6711616

Cited by 8 publications

(11 citation statements)

References 4 publications

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“…Note that the same assumption of grazing incidence has been made in both (13) and (14). The grazing incidence assumption is valid if the wavelength of interest is small compared to the tunnel transverse dimensions.…”

Section: Electric Field Polarized Predominantly In the Horizontal Dirmentioning

confidence: 99%

“…Those two-dimensional images are located within the same x-y plane as the source, with their coordinates given by [13]:…”

Section: Image Theorymentioning

confidence: 99%

“…In addition to the analytical form derived, the attenuation constant of the dominant mode can also be evaluated based on simulated or measured power distributions along the tunnel, provided that the separation distance is sufficiently long such that all the higher modes are significantly attenuated as compared to the dominant mode which has the lowest attenuation constant [13]. For a sufficiently long distance, the power decays linearly with the distance and the slope of the decay is the attenuation constant of the dominant mode.…”

Section: Introductionmentioning

confidence: 99%

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Attenuation Constants of Radio Waves in Lossy-Walled Rectangular Waveguides

Zhou¹,

Waynert²,

Plass³

et al. 2013

PIER

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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.

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Section: Electric Field Polarized Predominantly In the Horizontal Dirmentioning

confidence: 99%

“…Those two-dimensional images are located within the same x-y plane as the source, with their coordinates given by [13]:…”

Section: Image Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Attenuation Constants of Radio Waves in Lossy-Walled Rectangular Waveguides

Zhou¹,

Waynert²,

Plass³

et al. 2013

PIER

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“…The measured power distribution in a concrete tunnel with smooth walls is also plotted for reference. The details of the measurement can be found in [3]. The simulated results based on both the modal (dashed line) and ray tracing (marked with circles) methods are compared and shown to agree with each other well.…”

Section: B Ray Tracing Methodsmentioning

confidence: 74%

“…1) Tunnels with smooth walls: Based on the ray tracing theory, the electric field at an arbitrary point R(x, y, z) within a rectangular waveguide can be obtained by summing the scalar electric fields of the rays from all the images of the point source as [3]:…”

Section: B Ray Tracing Methodsmentioning

confidence: 99%

Modeling the influence of wall roughness on tunnel propagation

Zhou

Waynert

2014

2014 IEEE Radio and Wireless Symposium (RWS)

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At the ultra-high frequencies (UHF) common to portable radios, a mine tunnel is often modeled as a hollow dielectric waveguide. The roughness condition of the tunnel walls has an influence on radio propagation and therefore should be taken into account when accurate power predictions are required. In this paper, we derive a general analytical formula for modeling the influence of the wall roughness. The formula can model practical tunnels formed by four dielectric walls, with each having an independent roughness condition. It is found that different modes are attenuated by the same wall roughness in a different way, with higher order modes being significantly more attenuated compared to the dominant mode. The derivation and findings are verified by numerical results based on both ray tracing and modal methods.

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