scholarly journals High‐speed target imaging for vortex electromagnetic wave radar

2021 ◽  
Author(s):  
Yu‐Ang Zhou ◽  
Yong‐Zhong Zhu ◽  
Yi‐Jun Chen ◽  
He‐Feng Zhao ◽  
Wen‐Xuan Xie
Keyword(s):  
Electromagnetic Wave ◽  
High Speed ◽  
Wave Radar ◽  
Target Imaging

scholarly journals Use of Active Metamaterial as a Phase Shifter Integrated into the Waveguide

2021 ◽  
Vol 7 (1) ◽  
pp. 54-62
Author(s):  
Yu. Pasternak ◽  
E. Ishchenko ◽  
V. Pendyurin ◽  
S. Fedorov
Keyword(s):  
Electromagnetic Wave ◽  
Crystal Lattice ◽  
Fundamental Mode ◽  
High Speed ◽  
Phase Shifter ◽  
Control Method ◽  
Pin Diodes ◽  
Active Metamaterials ◽  
Electrodynamic Modeling ◽  
Electromagnetic Crystal

Active metamaterials usage is one of the most promising ways to control the characteristics of antennas, waveguides, and other microwave devices. This article proposes the controlled metamaterial design in the form of an electromagnetic crystal with switches located at the nodes of the crystal lattice. This metamaterial application for changing the fundamental mode phase of the WR-137 waveguide is investigated. Controlling the characteristics of the metamaterial is performed by switching pin diodes at the nodes of the lattice, so this control method allows you to achieve a high speed system, as well as to switch only certain pin diodes. Electrodynamic modeling was carried out, on the basis of which the characteristics of the waveguide were obtained for different metamaterial closed nodes combination, which changes the the electromagnetic wave phase.

scholarly journals Railway Track Recognition Based on Radar Cross-Section Statistical Characterization Using mmWave Radar

2022 ◽  
Vol 14 (2) ◽  
pp. 294
Author(s):  
Shuo Li ◽  
Jieqiong Ding ◽  
Weirong Liu ◽  
Heng Li ◽  
Feng Zhou ◽  
...  
Keyword(s):  
Real Time ◽  
High Speed ◽  
Continuous Wave ◽  
Great Influence ◽  
Railway Track ◽  
Support Vector ◽  
Data Set ◽  
Statistical Characterization ◽  
Wave Radar ◽  
Track Surface

The track settlement has a great influence on the safe operation of high-speed trains. The existing track settlement measurement approach requires sophisticated or expensive equipments, and the real-time performance is limited. To address the issue, an ultra-high resolution track settlement detection method is proposed by using millimeter wave radar based on frequency modulated continuous wave (FMCW). Firstly, by constructing the RCS statistical feature data set of multiple objects in the track settlement measurement environment, a directed acyclic graph-support vector machine (DAG-SVM) based method is designed to solve the problem of track recognition in multi-object scenes. Then, the adaptive chirp-z-transform (ACZT) algorithm is used to estimate the distance between the radar and the track surface, which realizes automatic real-time track settlement detection. An experimental platform has been constructed to verify the effectiveness of the proposed method. The experimental results show that the accuracy of track classification and identification is at least 95%, and the accuracy of track settlement measurement exceeds 0.5 mm, which completely meets the accuracy requirements of the railway system.

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