In this letter, a probe-fed reconfigurable dual-/triple-band circularly polarized (CP) Spidron fractal dielectric resonator antenna (SFDRA) is proposed. Initially, a dual-band CP SFDRA is designed. An eigen-mode simulation of an isolated SFDR concludes that the quasi-TM$_{11\delta }$ and quasi-TM$_{21\delta }$ are excited in the lower band, whereas the quasi-TE$_{12\delta }$ mode is excited in the upper CP band. The modes of the lower CP band are separated by etching a T-shaped slot from the ground plane, thereby achieving overall triple-band circular polarization. In addition, the TSS being $\lambda _g/2$ in length at 2.64 GHz produces a band-notch function. CP band reconfigurability is attained by placing a diode D1 across the width of the TSS such that the on-/off-state of the D1 radiates dual-/triple-band CP waves. The measurement results in the on-[off]-state show the impedance bandwidths for $\mathopen |$$S_{11}\mathclose |< $ $-$10 dB of 57.60% (2.2–3.98 GHz) [14.44% (2.12–2.45) and 40.48% (2.64–3.98 GHz)] and the 3 dB axial-ratio bandwidths of 24% (2.31–2.94 GHz) and 6.82% (3.68–3.94 GHz) [6.34% (2.29–2.44 GHz), 6.65% (2.76–2.95) and 7.09% (3.67–3.94 GHz)] in an ascending order of the frequency. A reasonable match is observed between the simulated and experimental data.

中文翻译：

---

可重构双/三波段圆极化介质谐振天线

在这封信中，提出了一种探针馈电可重构双/三频带圆极化 (CP) Spidron 分形介质谐振器天线 (SFDRA)。最初，设计了双频CP SFDRA。隔离 SFDR 的本征模式仿真得出的结论是，准 TM$_{11\delta }$ 和准TM$_{21\delta }$ 在低频段激发，而准 TE$_{12\delta }$模式在高 CP 波段激发。通过从接地平面蚀刻 T 形槽来分离较低 CP 波段的模式，从而实现整体三波段圆极化。此外，TSS 是$\lambda_g/2$在 2.64 GHz 的长度产生带陷函数。通过在 TSS 的宽度上放置一个二极管 D1 来实现 CP 波段的可重构性，使得上-/离开-D1 的状态辐射双/三频 CP 波。测量结果在上-[离开]-state 显示阻抗带宽 $\mathopen |$$S_{11}\mathclose |< $ $-$10 dB 的 57.60% (2.2–3.98 GHz) [14.44% (2.12–2.45) 和 40.48% (2.64–3.98 GHz)] 以及 24% (2.31–2.94 GHz) 和 6 . 3.68–3.94 GHz) [6.34% (2.29–2.44 GHz)、6.65% (2.76–2.95) 和 7.09% (3.67–3.94 GHz)]，按频率升序排列。在模拟数据和实验数据之间观察到合理的匹配。