In this letter, a characteristic mode analysis method is presented for ultra‐wideband radar cross‐section (RCS) reduction of microstrip antenna. By analyzing the magnitude of the modal weighting coefficients (MWCs), the important scattering modes can be found, which contribute a lot to the RCS of the antenna. Then, these scattering modes are suppressed through shape modification. To realize an ultra‐wideband RCS reduction (RCSR) of a ring‐shaped microstrip antenna, three pairs of slots are placed at suitable locations of the reference antenna to disrupt the current path, so as to suppress the important scattering modes while keeping the radiation modes work properly. Compared to the reference antenna, the proposed antenna achieves 6 dB RCSR on average over the frequency band of 0.5 GHz−5 GHz (163.64%) for x‐polarization incident wave. The peak reduction at 3.0 GHz is up to 23 dB. Meanwhile, the radiation performance keeps well. The measured and simulated results are in good agreement, which validates the presented method.

中文翻译：

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基于特征模态分析的环形微带天线超宽带雷达截面缩减

在这封信中，提出了一种特征模式分析方法，用于减少微带天线的超宽带雷达横截面（RCS）。通过分析模态加权系数（MWC）的大小，可以找到重要的散射模式，这对天线的RCS贡献很大。然后，通过形状修改来抑制这些散射模式。为了实现环形微带天线的超宽带RCS减小（RCSR），在参考天线的合适位置放置三对缝隙以扰乱电流路径，从而在保持辐射的同时抑制重要的散射模式模式正常工作。与参考天线相比，建议的天线在x的0.5 GHz-5 GHz（163.64％）频段上平均可实现6 dB的RCSR。极化入射波。3.0 GHz处的峰值降低高达23 dB。同时，辐射性能保持良好。实测结果与仿真结果吻合良好，验证了所提方法的有效性。