The Experts below are selected from a list of 54078 Experts worldwide ranked by ideXlab platform
Koichi Ogawa - One of the best experts on this subject based on the ideXlab platform.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
Kazuhiro Honda - One of the best experts on this subject based on the ideXlab platform.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
Jian Zhao - One of the best experts on this subject based on the ideXlab platform.
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Wave propagation in the vicinities of rock fractures under obliquely Incident Wave
Rock Mechanics and Rock Engineering, 2016Co-Authors: Jianchun Li, Lei He, Lyesse Laloui, Jian ZhaoAbstract:Though obliquely Incident plane Wave across rock fractures has been extensively investigated by theoretical analysis, the quantitative identification of each Wave emerged from fractures has not been achieved either in numerical simulation or laboratory experiment. On the other hand, there are no theoretical results describing the stress/velocity state of the rocks beside a fracture. The superposition of the multiple Waves propagating in the media results in the variation of the stress/velocity state. To understand the superposition of the Wave components in the adjacent rocks of a facture, based on the geometrical analysis of the Wave paths, the lag times among passing Waves at an arbitrary point are determined. The normalised critical distances from the fracture to the measuring locations where the corresponding harmonic Waves depart from other Waves for a certain duration are then derived. Discussion on the correction for an arbitrary Incident Wave is then carried out considering the changes of the duration of the reflected and transmitted Waves. Under the guidance of the analysis, Wave superposition is performed for theoretical results and separated Waves are obtained from numerical model. They are demonstrated to be consistent with each other. The measurement and the data processing provide an approach for Wave separation in a relatively unbounded media. In addition, based on the mechanical analysis on the Wave front, an indirect Wave separation method is proposed which provides a possibility for laboratory experiments of Wave propagation with an arbitrary Incident angle.
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obliquely Incident Wave propagation across rock joints with virtual Wave source method
Journal of Applied Geophysics, 2013Co-Authors: Jian ZhaoAbstract:Due to the presence of joints, Waves are greatly attenuated when propagating across rock masses. Zhu et al. (2011) (Normally Incident Wave propagation across a joint set with virtual Wave source method. J. Appl. Geophys.73, 283–288.) studied normally Incident Wave propagation across a joint set with the virtual Wave source method (VWSM). The introduced VWSM has merits in some aspects, especially the capability of separating differently arriving transmitted Waves. However, normal Wave incidence is only the special case for Wave incidence with arbitrary Incident angles. Obliquely Incident Wave propagation across a joint set is more complicated than normally Incident Wave propagation due to Wave transformation at the joints. As a continuation of the previous paper, this work is extended to analytically study obliquely Incident Wave propagation across joints with VWSM. Complete theoretical reflection and transmission coefficients across single joint described by displacement discontinuity model are derived through plane Wave analysis. The superposition of P Wave and S Wave is for the first time mathematically expressed and studied. The VWSM is verified through comparison with the propagation matrix method. Through extensive parametric studies on Wave transmission across single and multiple parallel joints, it is shown that transmitted Wave energy is mainly constrained in the transmitted Wave of the same type as the Incident Wave. And with increasing joint stiffness, the transmission coefficients across single joint increases except those whose Wave type is different from the Incident Wave. The amplitude of superposed transmitted Wave for P Wave incidence increases with Incident angle, which is coIncident with field observations. Both joint spacing and number of joints have significant effects on transmission coefficients. We find that when joint spacing is sufficiently large, the transmission coefficient is no longer a constant as the normally Incident Wave propagation case (Zhu et al., 2011). And when joints are very closely spaced, Wave attenuation depends little on the number of joints, which is different from the conclusions from equivalent medium method.
Xiaolin Huang - One of the best experts on this subject based on the ideXlab platform.
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effect of filling humidity on the propagation of high amplitude stress Waves through an artificial joint
Geotechnical Testing Journal, 2019Co-Authors: Xiaolin Huang, Wei Yao, Kaiwen XiaAbstract:The purpose of this article is to further investigate the seismic response of an artificial filled joint under high-amplitude stress Waves considering the effect of filling humidity, following our earlier work on dry infill. A steel split Hopkinson pressure bar system is utilized to induce high-amplitude stress Waves to the filled joint. In this study, the wet infill is a mixture composed of quartz sand, kaolinite clay, and water. It is found that when the water content is relatively low, i.e., 8.25 %, the seismic response of the joint with wet infill is similar to that of the joint with dry infill, as shown in the literature. When the stress Wave amplitude increases, the infill is progressively compacted and the transmission coefficient increases. However, there exists a crushing deformation stage for the infill in which many particles are crushed, and the transmission coefficient decreases as the Incident Wave amplitude increases. The water in the infill can reduce the friction between grains, which may lead to the decrease of the joint stiffness. As a result, the transmission coefficient is smaller than the case with dry infill under similar loading conditions. When the water content is moderate, such as 16.75 %, particles are very difficult to crush and the infill dominantly experiences compaction even when loaded by very high-amplitude stress Waves. Consequently, the transmission coefficient through the wet infill always increases with the increase of the Incident Wave amplitude. When the infill is fully saturated (water content = 25.0 %), it can only experience approximately elastic deformation, and few particles can be crushed. In this case, the transmission coefficient is independent of the Incident Wave amplitude. When the infill is dry or fully saturated, the transmission coefficient is insensitive to the amplitude of the Incident Wave.
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numerical simulation on seismic response of the filled joint under high amplitude stress Waves using finite discrete element method fdem
Materials, 2016Co-Authors: Xiaolin Huang, Kaiwen Xia, Qi Zhao, Giovanni Grasselli, Xuguang ChenAbstract:This paper numerically investigates the seismic response of the filled joint under high amplitude stress Waves using the combined finite-discrete element method (FDEM). A thin layer of independent polygonal particles are used to simulate the joint fillings. Each particle is meshed using the Delaunay triangulation scheme and can be crushed when the load exceeds its strength. The propagation of the 1D longitude Wave through a single filled joint is studied, considering the influences of the joint thickness and the characteristics of the Incident Wave, such as the amplitude and frequency. The results show that the filled particles under high amplitude stress Waves mainly experience three deformation stages: (i) initial compaction stage; (ii) crushing stage; and (iii) crushing and compaction stage. In the initial compaction stage and crushing and compaction stage, compaction dominates the mechanical behavior of the joint, and the particle area distribution curve varies little. In these stages, the transmission coefficient increases with the increase of the amplitude, i.e., peak particle velocity (PPV), of the Incident Wave. On the other hand, in the crushing stage, particle crushing plays the dominant role. The particle size distribution curve changes abruptly with the PPV due to the fragments created by the crushing process. This process consumes part of Wave energy and reduces the stiffness of the filled joint. The transmission coefficient decreases with increasing PPV in this stage because of the increased amount of energy consumed by crushing. Moreover, with the increase of the frequency of the Incident Wave, the transmission coefficient decreases and fewer particles can be crushed. Under the same Incident Wave, the transmission coefficient decreases when the filled thickness increases and the filled particles become more difficult to be crushed.
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propagation of high amplitude stress Waves through a filled artificial joint an experimental study
Journal of Applied Geophysics, 2016Co-Authors: Xiaolin Huang, Kaiwen Xia, Hong Zheng, Bowen ZhengAbstract:Abstract This paper investigates the propagation of high amplitude stress Waves through a filled joint using a modified steel split Hopkinson pressure bar (SHPB) system. Quartz sand fillings with various thickness are placed in a steel tube and then sandwiched between the Incident and transmitted bars to simulate the filled rock joints. Using SHPB, the Incident stress Waves with similar frequency spectrum but varying amplitude are induced to load the artificial filled joints. The particle size distributions of the fillings after tests are analyzed. It is discovered that as the amplitude of the Incident Wave increases, the fillings experience three stages of deformation: initial compaction, crushing and crushing and compaction. In the initial compaction stage and the crushing and compaction stage, the fillings are mainly compacted, and thus the transmission coefficient increases with the amplitude of the Incident Wave. However in the crushing stage, the transmission coefficient decreases with the increase of the amplitude of the Incident Wave. This is a result of energy consumption due to particle crushing. The observed dependence of the transmission coefficient on the Wave amplitude is consistent with the particle size distribution of recovered fillings.
Taiki Fukushima - One of the best experts on this subject based on the ideXlab platform.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
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development of a circular phased array 4 4 mimo antenna for ad hoc connected car system
Asia-Pacific Microwave Conference, 2017Co-Authors: Kazuhiro Honda, Taiki Fukushima, Koichi OgawaAbstract:To ensure the success of upcoming vehicular ad hoc networks (VANETs), we are currently developing a 4 × 4 multiple-input multiple-output (MIMO) antenna system utilizing a phased array in a circular configuration. The circular phased array 4 × 4 MIMO antenna generates four radiation patterns with the peak gain at the angle of Incident Wave by reorganizing the antenna elements. The proposed antenna provides a high level of MIMO channel capacity regardless of the variations in the angle of Incident Wave, demonstrating that gigabit high-speed communications can be realized using the proposed antenna.
