四频段高效率、低交叉极化双偏置反面天线设计道.doc

四频段高效率、低交叉极化双偏置反射面天线设计 何山红1 郝文倩2 陈敏2 安徽工业大学电气信息学院马鞍山 2430021 南京理工大学电光学院南京 2100942 摘 要论文设计了一幅工作于Ku/Ka四频段的高效率低交叉极化的偏置双反射面天线。馈源采用宽频带小张角环加载混合模波纹喇叭。为了提高天线效率及降低天线交叉极化电平反射面采用了对称结构的双偏置赋形反射面。在优化得到馈源结构并计算得出馈源幅度、相位方向图后论文最后利用物理光学方法计算了天线的远场方向图并和标准双偏置反射面天线进行了对比分析结果表明在所有频带内天线具有的平均天线效率且交叉极化电平低于-35dB。 2.77关键词四频段宽频带双偏置赋形反射面高效率交叉极化 Design of Four Bands Dual-Offset Shaped Reflector Antenna and With Low Cross-Polarization and High Efficiency ShanHong HE1 WenQian HAO2 Min Chen2 Sch.of Elec.Eng. Infor.Anhui University of Technology.Ma??anshan243002China1 Sch.of Elec.Eng. OpticsNanjing University of Science Technology. Nanjing 210094China2 Abstract: In this papera high efficiency dual-offset shaped reflector antenna operating in the four bands of Ku/Ka bands with low cross-polarization levels is designed. The ring loaded corrugated horn with small flare angle operating in hybrid mode is used as the feed of the reflector antenna. In order to decrease the cross-polarization level of the antennathe dual-offset shaped reflector with symmetrical structure is adopted. Based on these radiation patters of magnitude and phase of the optimized feedthe far field radiation patterns of the reflector antenna are obtained by the physical opticsPOmethod and are compared with these of the normal dual-offset reflector antenna. The simulated results show that the average efficiency of the designed antenna in the whole bands is 77.2 and the cross-polarization levels are less than -35dB. Keywords: Four band Broad bandwidth Dual offset shaped reflector High efficiency Cross-polarization 1 引言 随着卫星通信事业的蓬勃发展Ku和Ka收发共用四频段反射面天线的研究受到了广泛的重视。卫星通信天线不但需要效率高交叉极化电平低还需要满足特定的旁瓣包络电平等特性。双偏置反射面天线避免了副面对主面的遮挡和馈源及支杆对副面的遮挡进而改善了次级辐射方向图的近轴旁瓣特性和馈源的输入电压驻波比特征在车载卫星通信等领域得到了广泛应用。对称转换的标准双偏置反射面天线虽然具有良好的交叉极化电平但效率较低1。因此论文采用了具有对称结构的赋形双偏置反射面2。由于该天线最高工作频率与最低工作频率的比值超过了2.5对波纹喇叭馈源的设计提出了苛刻的要求34。论文通过优化小张角混合模环加载波纹喇叭的结构尺寸并辅以合理选择反射面的几何结构参数在副面照射区域内在所有 ·619· 频段内获得了近似一致的幅度、相位馈源方向图。得到馈源幅、相方向图后论文再利用口面分布函数赋形设计了反射面的几何结构并用物理光学方法计算了该反射面天线的性能。 a b c 图1 仿真的馈源幅度和相位