基于频率选择表面的宽角扫描阵列

Wide-angle scanning array based on frequency selective surface

设计并加工了一种基于双层频率选择表面(frequency selective surface,FSS)的一维Vivaldi阵列天线.首先采用周期边界条件分析无限大阵列中的单元特性,利用等效传输线原理和广义散射参数矩阵来设计优化加载在Vivaldi阵列上方的介质宽角匹配层.然后,在所加载的双层介质匹配层表面直接印制FSS结构使阵列扫描特性得到极大改善.仿真和实测结果表明,一维Vivaldi阵列中心单元在7~12GHz的有源驻波比均小于2.5,在8~10GHz波束扫描范围能够达到±60°.仿真结果还表明:采用双层FSS结构的Vivaldi阵列与未加载匹配层的Vivaldi阵列相比,在7~11.5GHz增益有2~4dB的提高;同时在扫描至±60°时,FSS结构的加载使得阵列在对应扫描角下的交叉极化下降了5~10dB.

A dimensional Vivaldi antenna array with double layer of frequency selective surface（FSS） is designed and processed in the paper. The periodic boundary condition is adopted to analyze infinite element characteristics of array, and the equivalent transmission principle and the generalized scattering matrix is used to design and optimize all parameters of loading layer of the wide angle matching on the top of the Vivaldi array. Then, FSS is printed directly on the surface of dielectric layer and scanning characteristics of the array is improved significantly. Simulation and measured results show that, active standing wave ratio of the center element in the array is less than 2.5 around 7-12 GHz, and beam scanning range can reach 60° in 8-10 GHz. The simulation results show that gain of Vivaldi array with double FSS structure is 2-4 dB higher than that without matching layer in range of 7-11.5 GHz. Meanwhile, when scanning to 60°, the cross polarization of the array loaded with FSS is decreased by 5-10dB.