Effect of Antenna Location and Polarization on Radio Wave Propagation in Tunnel

Zhao, Zhenyu; Hou, Weibin; Wang, Junhong

doi:10.1109/icmmt45702.2019.8992522

Cited by 7 publications

(9 citation statements)

References 9 publications

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“…Content may change prior to final publication. difference between the path loss curves obtained by a diversity antenna pair and a single antenna, this paper uses the median field intensity proposed in [22] and the system field strength flatness factor proposed in [23] to evaluate the slow and fast fading characteristics of the received power, respectively, for the cases of a single antenna and a diversity antenna pair. The isolation between two receiving or transmitting antennas of a transmitting diversity antenna pair or receiving diversity antenna pair and the channel capacity are provided.…”

Section: Diversity Results and Discussionmentioning

confidence: 99%

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Optimized Scheme of Antenna Diversity for Radio Wave Coverage in Tunnel Environment

et al. 2020

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To suppress the deep fading of radio waves caused by the tunnel waveguide effect, this paper presents an optimized scheme for the spatial and polarization diversities of tunnel antennas. Through the correlation coefficient analysis of path loss curves obtained by antennas placed at different positions, the two antenna positions that generate path loss curves with the lowest correlation coefficient are found, and these two antennas are defined as a diversity antenna pair. Using this scheme, the spatial diversity properties of the transmitting antenna and receiving antenna, as well as the spatial-polarization combined diversity property of the transmitting antenna, are obtained. Furthermore, the impact of antenna polarization on the spatial diversity property is investigated. The performance of the proposed scheme for spatial and polarization diversities is evaluated in terms of the intensity and uniformity of the path loss. The simulation results illustrate that the proposed diversity optimization scheme can suppress the influence of the waveguide effect and achieve more uniform and flatter radio wave coverage in a tunnel environment.

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Section: Diversity Results and Discussionmentioning

confidence: 99%

“…x is the length of the tunnel and s A is the system median field intensity defined in [22]. The expressions of the system field strength flatness factor, which reflects the flatness characteristics of the received power, are given by…”

Section: Diversity Results and Discussionmentioning

confidence: 99%

Optimized Scheme of Antenna Diversity for Radio Wave Coverage in Tunnel Environment

et al. 2020

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“…To observe the impact of environment on radio wave coverage more intuitively, in addition to directly comparing the difference between the received power curves, this paper also uses the parameters, median field intensity (MFI) proposed in [28] and system field strength flatness factor (FLmax) proposed in [29], to evaluate the large-scale fading and small-scale fading characteristics of the radio wave coverage along the receiving path, respectively. For the simulation environment of this paper, the formula of MFI is expressed as…”

Section: Evaluation Parameters For Different Simulation Casesmentioning

confidence: 99%

Effect of Beam Angle of the Transmitting Antenna on Radio Wave Coverage in the Region Containing Tunnel Entrance

2022

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Radio wave coverage in open-confined mixed space along the railway is studied in this paper. The space along the railway can be classified into three kinds of spaces, that are, open space, confined space and the open-confined mixed space. The open-confined mixed space locates between the open space and confined space. In order to reveal the radio wave coverage mechanism in the open-confined mixed space and find out the important influence factors, the influence of antenna gain, antenna position, tunnel crosssection shape, and beam angle on the radio wave coverage in the open-confined mixed space are studied. Considering the complexity of environment, the radio wave coverage is modeled by finite difference time domain method. The simulation results show that the radio wave coverage is sensitive to the beam angle of transmitting antenna. And the variation law of radio wave coverage with the beam angle shows a certain correlation with the transmitting antenna position and tunnel cross-section shape. 11 12 157 utilizes a one-cell overlap region to exchange the information 158 between adjacent sub-domains. In the algorithm, only the 159 tangential magnetic fields are exchanged at each timestep. 160 B. MODELING OF OPEN-CONFINED MIXED AREA 161 In this paper, the Yagi-Uda antenna is placed along x-axis 162 in open space. The fine mesh numbers for simulating the 163 antenna region are 300 × 200 × 300 cells, and the equivalent 164 surface for output the tangential field component occupy 46, 165 31 and 46 coarse cells in x, y, and z directions, respectively. 166 For the total simulation environment, there are 1064 × 224 167 × 200 coarse mesh cells, which contain a 10-meter-long 168 open area and a 25-meter-long tunnel. Two tunnels with 169 different cross-sectional shapes are considered, namely rect-170 angular tunnel and arched tunnel. The specific dimensions

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“…The size of a reception sphere should guarantee at least one hit per wavefront in order not to underestimate the electric field. On the other hand, a radius of the reception sphere given by (12) does not exclude the possibility of several hits per wavefront. This leads to a doubling of the field strength, i.e., to a power error of +6 dB per erroneously counted ray.…”

Section: B Double Countingmentioning

confidence: 99%

Inconsistent Rays in Propagation Prediction by Ray Launching in Rectangular Tunnels

Novak

2022

IEEE Access

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Ray tracing is replacing the less accurate statistical and empirical approaches of radio channel modeling. Although being high-frequency asymptotic method, ray tracing has been shown to be mathematically equivalent to purely analytical modal methods in rectangular tunnels and waveguides. The equivalence applies to modeling reflections using image theory, while other variants of the ray tracing algorithm are still subject to approximation errors that can systematically add up. Failure to recognize this leads to indiscriminate use of the less appropriate algorithmic variants. In particular, the use of ray tracing by ray launching can be questionable in tunnel environments, at least when characteristic sequences are used to avoid double counting errors. In addition to the known path inaccuracies, we first identify previously untreated inconsistent rays as the most problematic, leading to a significantly overestimated signal at distances greater than 100 m. We show that the problem is not equivalent to double counting of rays since the inconsistent rays represent valid wavefronts for the points in space at which they are detected. The discrepancy arises from the use of reception spheres, which allow some spatial displacement of ray paths. We quantify the errors in terms of estimated power, channel impulse response, and delay spread in a rectangular tunnel. We propose an improvement in the double-count filters to detect inconsistent rays. However, evaluation of signals deeper in the tunnel at frequencies below 1 GHz must be avoided by ray launching due to the remaining path inaccuracies.

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Effect of Antenna Location and Polarization on Radio Wave Propagation in Tunnel

Cited by 7 publications

References 9 publications

Optimized Scheme of Antenna Diversity for Radio Wave Coverage in Tunnel Environment

Optimized Scheme of Antenna Diversity for Radio Wave Coverage in Tunnel Environment

Effect of Beam Angle of the Transmitting Antenna on Radio Wave Coverage in the Region Containing Tunnel Entrance

Inconsistent Rays in Propagation Prediction by Ray Launching in Rectangular Tunnels

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