一种双频段圆极化移动导航终端天线的设计

给出了一款应用于北斗导航卫星系统(CNSS)B1频段/S频段的双频圆极化缝隙天线的设计方法。该天线采用微带线进行馈电,在地板上开有两个方形螺旋槽,其总槽长度大约均为一个自由空间操作波长。通过调节螺旋槽的终点处的长度即可获得最适宜的轴比,从而实现圆极化。另外,还可以通过调节螺旋槽的宽度来获得较大的轴比带宽。在地板中央切去一个圆环形槽可增大感应电流的路径,从而降低圆极化的中心频率。通过仿真软件HFSS对天线结构参数进行优化设计,并制作实物。其仿真及实测结果表明:回波损耗小于-10 dB的阻抗带宽为38.5%,且在阻抗带宽内天线的相对轴比带宽也达到了大约5%。

Design of a dual-band circularly polarized mobile navigation terminal antenna

A design method of dual-band circularly polarized slot antenna is proposed, which is used in B1 frequency band and S frequency band of Beidou navigation system. The antenna use microstrip line to feed. Two square spiral grooves were opened on the lfoor, and the length of total slot is about a free space operating wavelength. By adjusting the length of the spiral groove in terminal, the optimum axial ratio can be obtained, thus circular polarization can be achieved. In addition, a greater axial ratio bandwidth can be achieved by adjusting the width of the spiral groove. An annular groove is cut off in the middle of the lfoor to increase the path of induced current, thus to reduce the center frequency of the circular polarization. The structure parameters of the antenna are optimized by HFSS, and an antenna is fabricated based on the simulation. The simulation and measured results show that the impedance bandwidth with S11＆lt;-10 dB is 38.5%, and the relative axial ratio bandwidth of antenna within the impedance bandwidth has reached about 5%.