基于特征模理论的共形阵列天线散射对消设计

Design of Scattering-cancellation Conformal Array Antenna Based on Characteristic Mode Theory

摘要:

针对共形阵列天线的散射对消设计进行研究，基于特征模理论指导对共形微带天线单元的辐射和散射进行特征模式分析，设计了一种加载寄生贴片的新型微带天线结构，实现了对共形单元辐射和散射模式的独立调控；在保证辐射模式不变基础上，通过调节寄生贴片枝节长度调控共形单元的散射模式相位，使参考单元和设计单元的散射模式电流方向相反，将其组成4×4共形阵列天线，通过两种单元的散射模式对消实现RCS缩减；仿真结果表明，在工作频段5.09~5.89 GHz内，设计共形阵列天线增益下降小于0.1 dB，在4~8 GHz频带内实现了RCS缩减，带内x极化RCS缩减均值为19.4 dB，缩减峰值达21.8 dB；与传统平面微带阵列天线散射对消设计方法相比，采用特征模理论进行共形阵列天线散射对消设计综合了共形单元散射模式相位及空间相差引入的相位，为准确指导共形阵列天线散射对消设计提供了新的设计方法。

Abstract:

The scattering cancellation design of a conformal array antenna is investigated, and the radiation and scattering modes of a con-formal microstrip antenna is analyzed by characteristic mode theory. The new microstrip antenna structure loaded with parasitic patches is designed which is realizing the independent regulation of the radiation and scattering modes of the conformal cell. The phase of the scattering pattern of the conformal unit is regulated by adjusting the length of the parasitic patch branches, so that the scattering pattern currents of the reference unit and the design unit are in the opposite direction, and the radiation pattern can re-main unchanged. The 4×4 conformal array antenna will be composed of the reference cell and the designed cell to realize the RCS reduction through the scattering cancellation of the two types cells. Simulation results show that the gain reduction of the proposed conformal array is less than 0.1 dB within the operating band 5.09~5.89 GHz, and the RCS reduction is achieved within the 4~8 GHz band. The mean value of the RCS reduction of the in-band x-polarization is 19.4 dB and the peak value of the RCS reduction reaches 21.8 dB. Compared with the traditional scattering cancellation design method used in planar microstrip array antennas, the scattering cancellation method for conformal array antenna is based on characteristic mode theory. The phase of scattering modes of the conformal units and the spatial phase difference is both taken into consideration, which provided a new design method for accurately guiding the conformal array antenna.