Research On Electromagnetic Characteristic Of Balise System In High-Speed Railway

ABSTRACT:With the rapid development of high-speed railway, the way about how to ensure transport safety becomes much more important. CTCS(Chinese Train Control System) technical specifications were laid down by our country according to ETCS(European Train Control System), and much research about CTCS was carried out. The theory and technology of balise is a very important part of CTCS.A detailed research about the operation principles of balise and the theory of RFID has been done. The electromagnetic relationship between reader and transponder in RFID system was converted to analysis of circuit, which was the basis of later research. The contribution of this dissertation is presented as follows:First, the BTM antenna and balise antenna which operate at 27.095MHz and 4.234MHz respectively were designed. The effect of antenna size on inductance was analyzed and proper antenna parameters were chose to facilitate the design work of the matching circuit. The effect of Q factor on antenna was also analyzed and proper value was chose to get the desired bandwidth.Second, a method of capacitor matching was proposed, which could make the antenna operate at desired frequency and the resonant impedance equal to the output impedance of the cable. Simulation analysis of both BTM antenna and balise antenna has been done to verify the structure of the antenna. Meanwhile, the Doppler Effect when the train travels at high speed was analyzed to study the effect on signals received by the antenna.Third, the sample of BTM antenna was fabricated and the comparison between the test results and simulation results was made. It was shown in the test that the performance of the antenna could be better by adjusting the parameters of the matching components, that is to say, the return loss could be lower and the bandwidth could be wider. The effect of metal to the BTM antenna was also studied and the performance of the BTM antenna was compared when the distance between the BTM antenna and the metal plate varied.At last, a conclusion of the dissertation was made and the direction for future research was pointed out.