Research On Performance Of Signal Transfer In Leaky Waveguide Of CBTC

ABSTRACT:Nowadays, CBTC have been applied in more and more lines of urban mass transits with its development. Leaky waveguide has a good anti-disturbance capacity with the stable signal through the results of test for operation line and testing line. Leaky waveguide has been applied in DCS of CBTC successfully.As leaky waveguide is mainly applied in elevated bridge section of line of urban mass transits, it will be influenced by extremely bad weather. It is important for guaranteeing the system to operate normally to simulate and test the extreme case, such as absorbing water, absorbing metal, and covered by snow, during operation and testing.This paper simulates and analyzes leaky waveguide with HFSS, a software for high frequency electromagnetic simulation, aiming at the related problems caused from operating leaky waveguide of CBTC. Combining data of testing lines and operation lines, this paper analyzes the performance of WLAN signal, which is used to transmit data in CBTC.First, this paper introduces the principle of leaky waveguide, describing the methods of modeling for leaky waveguide with finite element theory; then this paper establishes the transmission model of leaky waveguide with HFSS, simulating and analyzing three extreme cases:absorbing water, covered by snow, and absorbing metal. Combining with data in lines, the results of simulation are analyzed, and the models are optimized. The results of simulation can be considered as reference for applying and maintence of leaky waveguide.Due to the limited context and theory knowledge of author, this paper has not researched the electromagnetic theory deeply. Therefore, some problems, such as that how does relative permittivity the performance of WLAN signal in leaky waveguide, need to be solved further.