Research Of New Dual-band Beltbutler Matrix

With the development of economy, the number of cars in our country is becoming more and more, which has been much higher to load of highway in our country.Due to the huge number, the efficiency of highway toll stations has seriously affected the smooth operation of the vehicle. Vehicle passes the toll station, need to stop and pay cost, thus affects the load of the highway, the ETC charge system, can realize the function without a stop payment, therefore, to improve the highway load has a great help.ETC charging system by transmitting antenna array, and the antenna feed network usually uses the Butler matrix, the matrix can through to the antenna position and phase adjustment, to achieve the beam synthesis effect of different directions.Firstly,this paper introduces the development status of the ETC, contrasted the Butler matrix and the advantages of other ways of feeding, at the same time, corresponding to the ETC charge system of radiation antenna and duplexers are introduced. In this paper, also the Butler matrix are analyzed from the aspects of theory, the theoretical foundation of the Butler matrix are introduced, transmission line theory; Analysis, multiport network theory, as well as the matrix of Butler, 3 db directional coupler and phase shifter, finally, the characteristics of the Butler matrix are analyzed.This paper also gives a 3 db directional coupler and general design method of phase shifter, over this basis, through the load line, the method of binary designed to 2.4 GHz and 5.8 GHz two frequency point can work simultaneously double-frequency 3 db directional coupler and phase shifter, through the calculation of its parameters, determine the geometry size, and modeling and simulation in the CST, get ideal results; Based on the designed double-frequency 3 db directional coupler and phase shifter through a transmission line connection, get the dual-band Butler matrix, the same simulation, can be seen from the results, the designed Butler matrix in the work frequency points, input port of the return loss under- 10 db, the transmission coefficient of output port are close to 6 db, showed that the dual-frequency Butler matrix has good characteristics.At the end of the paper for the designed double-frequency Butler matrix for processing and testing, the results show that the measured results and simulation results are in good accord with, can satisfy the application requirements.