A dual‐band cavity‐backed circularly polarized crossed‐dipole antenna with double split‐ring resonators (SRRs) is investigated in this paper. A pair of crossed dipoles connected by concentric ring‐delay lines is firstly designed as a circularly polarized (CP) antenna with only one CP mode. To extend the operation of the original design, a pair of the λ/4‐resonance SRRs are used to realize wider axial ratio bandwidth at higher band. At the same time, another pair of the λ/4‐resonance SRRs with larger dimension is adopted to obtain a lower frequency band, although the effect is not very satisfying. Then the cavity‐backed technology and a defected ground structure are both employed to improve the working bandwidth. The dual‐band CP antenna can be tuned into a wide bandwidth one by changing the dimensions of the larger SRRs. A good agreement between the simulated and measured results can be observed. The measured impedance bandwidths are 6.90% (3.36‐3.60 GHz) and 53.58% (4.40‐7.62 GHz). The measured 3‐dB AR bandwidth is 7.93% (3.39‐3.67 GHz) and 59.15% (4.08‐7.51 GHz).

中文翻译：

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具有双裂环谐振器和有缺陷的接地结构的双频带圆极化交叉偶极子天线

本文研究了具有双裂环谐振器（SRR）的双频带腔背圆极化交叉偶极子天线。通过同心环形延迟线连接的一对交叉偶极子首先被设计为仅具有一种CP模式的圆极化（CP）天线。为了扩展原始设计的操作，使用一对λ/ 4共振SRR在更高的频带上实现更宽的轴向比带宽。同时，采用另一对较大尺寸的λ/ 4共振SRR获得较低的频带，尽管效果并不十分令人满意。然后，采用后腔技术和有缺陷的地面结构来提高工作带宽。通过更改较大的SRR的尺寸，可以将双频带CP天线调谐到一个宽带宽天线。可以观察到模拟结果与测量结果之间的良好一致性。测得的阻抗带宽为6.90％（3.36-3.60 GHz）和53.58％（4.40-7.62 GHz）。测得的3-dB AR带宽为7.93％（3.39-3.67 GHz）和59.15％（4.08-7.51 GHz）。