Design And Research On Vehicle Mounted Measuring Antennas

The rapid development of wireless communication technologies leads to a complicated electromagnetic environment, which has spawned various wireless measuring systems. At the same time, some practical demands such as high mobility, real time, low cost and low profile make people install the wireless measuring systems on the vehicles. Therefore, the technologies of vehicle-mounted wireless measuring system have become hot research topics, one important part of which is the vehicle-mounted measuring antenna.In this paper, two kinds of vehicle-mounted antennas are proposed and measured. The first one is a vehicle-mounted amplitude-compare direction finding antenna array. At First, a monopole Vivaldi antenna is designed to lower the profile of the antenna, which is based on the traditional Vivaldi antenna. Then in order to achieve a relative consistent main lobe width, a minimized beam forming multiplexing network is proposed. In this network, three antenna units work with array in the low frequency band and single antenna unit works alone in the high frequency band. Finally after the integration of the array, a metal round plate is used to reduce the vertical radiation and improve the horizontal gain. The measured resultsis good. The measured results shows that each antenna unit has a 3dB beamwidth closing to 45 degrees in 790-960MHz and 1710MHz-2700MH, at the same time, the gain changes linearly in the main lobe.The second one is a vehicle-mounted continuous wave Doppler radar antenna. Based on the substrated intergrated waveguide technology, we summarized the design procedure of the low sidelobe longitudinal slot antenna array is summarized and three kinds of low sidelobe longitudinal slot antenna array used in vehicle mounted system is designed. They are 8×12 array with tree shaped power divider,8×12 array with T-shaped power divider and 8×12 array with dual feeding ports. According to the measuring results, the 8 X 12 array with tree shaped power divider has a E-plane sidelobe below-25dB and H-plane sidelobe below-30dB. The second array based on a T-shaped divider has a-25dB E-plane sidelobe and-30dB H-plane sidelobe. Finally, the 8 X 12 array with dual feeding ports has a-25dB E-plane sidelobe and-30dB H-plane sidelobe compared with the simulation.