Scaled Modeling and Measurement for Studying Radio Wave Propagation in Tunnels

Jacob Gerasimov,Egor Liokumovitch,Yosef Pinhasi,Michael Gerasimov,Gad A Pinhasi,Yair Richter,Nezah Balal,Eran Bamani

doi:10.3390/electronics10010053

Jacob Gerasimov, Egor Liokumovitch + Show 6 more

Open Access

https://doi.org/10.3390/electronics10010053

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Journal: Electronics	Publication Date: Dec 31, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Ariel University

Abstract

The subject of radio wave propagation in tunnels has gathered attention in recent years, mainly regarding the fading phenomena caused by internal reflections. Several methods have been suggested to describe the propagation inside a tunnel. This work is based on the ray tracing approach, which is useful for structures where the dimensions are orders of magnitude larger than the transmission wavelength. Using image theory, we utilized a multi-ray model to reveal non-dimensional parameters, enabling measurements in down-scaled experiments. We present the results of field experiments in a small concrete pedestrian tunnel with smooth walls for radio frequencies (RF) of 1, 2.4, and 10 GHz, as well as in a down-scaled model, for which millimeter waves (MMWs) were used, to demonstrate the roles of the frequency, polarization, tunnel dimensions, and dielectric properties on the wave propagation. The ray tracing method correlated well with the experimental results measured in the tunnel as well as in a scale model.

Highlights

Over recent decades, changes in lifestyle and frequent drives between cities have led to a large increase in roads for transportation and increased use of underground infrastructures, such as tunnels, mines, corridors, and other underground passways
radio frequencies (RF) propagation in tunnels significantly differs as compared to above ground propagation. One reason for this is that, in tunnels, the far-field attenuation is generally lower than that of freespace [1,2,3]; researchers are working toward the understanding and the ability to precisely model the propagation of radio waves as a tool for improving communication and tracking systems
Evaluation of the radio wave propagation in an underground tunnel environment is important for the appropriate design of wireless links and networks

Summary

Introduction

Changes in lifestyle and frequent drives between cities have led to a large increase in roads for transportation and increased use of underground infrastructures, such as tunnels, mines, corridors, and other underground passways. The prediction of wave propagation in an underground environment is troublesome due to the short wavelength relative to objects of different dimensions and shapes. The main differences between pedestrian and transport tunnels and mines are the dimensions and cross-sections, parameters that significantly impact the wave propagation [19,20] and electromagnetic properties [21]. Car and train tunnels are usually wide with low ceilings while pedestrian tunnels are narrow and have high ceilings These differences affect the frequency and polarization of the transmitted waves. In this paper we report on the results of a field experiment performed in a pedestrian tunnel with a relatively small cross-section: a height of 1.85 m and width of 1 m. A good fit between the scale model experiments and the simulation demonstrates that scale models can be used to imitate real-world experiments in a laboratory environment

Properties of Tunnels and Systems and Their Effect on Propagation

Scaling the Ray Tracing Model

Wave frequencies and respective scaling

4.4.Experiments

53 PEER REVIEW

ScaleAs

Conclusions