星载赋形波束单馈源单偏置反射面天线设计

Design of a Satellite-born Contoured-beam Antenna with Single Feed and Single Offset Reflector

为了使星载赋形波束天线远场方向图与服务区形状匹配良好,并且在波束覆盖区内具有较平坦的方向性系数,将表征反射面形状的Zernike多项式展开系数作为优化变量,建立基于最小P乘法和Minmax方法的适应度函数,利用进化算法进行赋形反射面天线优化。利用该方法设计了覆盖中国大陆和巴西的赋形波束反射面天线。仿真结果表明,天线远场方向图与服务区形状均匹配良好,服务区内的方向性系数波动量分别为2.31 d B和11.23 d B,该值比现有方法小,并且该方法具有较高自由度及收敛性好的特点。

An optimization method is proposed to match the shape of the service area well with far-field pattern of satellite antenna,and maintain directivity as constant as possible within the desired beam coverage.In this method,the expansion coefficients of the Zernike polynomial charactering the reflector structure are optimized based on the fitness function which is a combination of the least Pth and Minmax methods.The evolutionary algorithm is adopted to calculate the optimal parameters.To verify the proposed method,shaped-beam reflector antennas covering China mainland and Brazil have been designed.The simulation results show that the far-field radiation pattern is in a good alignment with the service area,and the fluctuations of directivity are less than 2.31 dB and 11.23 dB,respectively,which outperforms the existing methods.And the method has the characteristics of high degree of freedom and good convergence.