A circularly symmetric high impedance surface (HIS)-based low-profile circularly polarized antenna with stable phase center is investigated. The antenna consists of a series-fed eight-arm spiral slot antenna and a circularly symmetric HIS (CSHIS) used as the ground plane. As the use of CSHIS, the profile of antenna is decease to as low as 0.09λ (λ is the free space wavelength), while the phase center of the antenna maintains stable. Also, the gain of the presented antenna is enhanced compared with that utilizing HIS with rectangular unit cell. For verifying, a prototype of the antenna was fabricated and measured. The measured results show that the overlap bandwidth of 3-dB axial ratio and impedance matching covers 1.14–1.45 GHz (23.9%), and the gain can reach as high as 7.79 dBic. Over the operation band, stable phase center also can be observed.

中文翻译：

---

基于圆对称高阻抗表面的低剖面圆极化天线

研究了一种基于圆对称高阻抗表面 (HIS) 的具有稳定相位中心的低剖面圆极化天线。天线由串联馈电的八臂螺旋缝隙天线和用作接地平面的圆形对称 HIS (CSHIS) 组成。由于使用了 CSHIS，天线的轮廓降低到 0.09 λ ( λ是自由空间波长），而天线的相位中心保持稳定。此外，与使用矩形单位单元的 HIS 相比，所提出的天线的增益得到了增强。为了验证，制作并测量了天线的原型。实测结果表明，3-dB轴比与阻抗匹配的重叠带宽覆盖1.14-1.45 GHz（23.9%），增益可达7.79 dBic。在工作频带上，也可以观察到稳定的相位中心。