Research On "A" Interface Antenna Of Controlled Balise

The balise is a vehicle-to-ground information transmission device based on the electromagnetic coupling mechanism,which is widely used in China's high-speed rail and urban orbit,but the existing balise system is unidirectional transmission.The two-way transmission of the balise can make the ground obtain more vehicle information and realize closed loop of the point.It can also verify whether the code sequence uploaded from the balise is correct and replace the part of the rail next to the equipment in order to detect whether the train enters are in or out of a section.But also it can help the traffic in a larger place to achieve a safe double door in the subway.In order to realize the bidirectional transmission of the controlled balise system,this thesis proposed a two-way balise implementation method by studying the working principle of the bidirectional balise.The key part to realize the bidirectional communication is the bidirectional communication of the "A" interface antenna.The main work of this thesis is as follows:(1)The principle of bidirectional communication controlled balise system is analyzed,and the initial implementation scheme of bidirectional communication is proposed.It is pointed out that the key to realize two-way communication lies in the two-way communication of "A" interface antenna.(2)According to the transmission demand and antenna design theory of the controlled balise downlink,the antenna with the required requirements is designed.The electromagnetic field model of the balise "A" interface antenna is established by using the electromagnetic simulation software.The correctness of the model is verified by the theoretical calculation and the analysis The transmission performance of the downlink antenna,the simulation results show that the antenna can meet the transmission needs.(3)In this thesis,the realization of the antenna transceiver isolation is proposed to join the duplexer between the antenna and the receiver and the transmitter to solve the mutual interference caused by balise uplink and downlink information transmission at the same time.The simulation verifies the performance of duplexer and the results show that the designed duplexer can realize the isolation.(4)It is verified whether the designed antenna and transceiver isolation meet the requirements.The simulation results show that the designed antenna and transceiver isolation meet the transmission requirement of the controlled balise by connecting with the A / C interface antenna,duplexer,receiver and transmitter.