加载介质透镜的超宽带平面螺旋天线设计

Design of an Ultra-wideband Planar Spiral Antenna Loaded with Dielectric Lens

针对乳腺癌检测、成像等医疗领域对天线高增益及宽频带的需求,研究设计了一款加载介质透镜的超宽带平面螺旋天线。该天线采用双臂平面阿基米德螺旋天线作为辐射单元,在辐射臂外围间隔一定距离处加载金属圆环以改善驻波性能,并由指数渐变式微带巴伦作为馈电结构。天线顶部加载介质透镜,底部设置金属圆台形反射背板,实现了调整波束形状和提高天线增益的目的。加装圆柱形天线罩后天线高度约为87.53 mm,直径约为46.50 mm。仿真结果显示,天线在3~12 GHz工作频带内回波损耗小于-10 dB,辐射方向图呈现良好的定向辐射特性,实测结果与仿真结果基本一致。

Aiming at the high gain and broadband requirements from the medical fields,such as breast cancer detec-tion,imaging,and so on,this paper presents an ultra-wideband planar spiral antenna loaded with a dielectric lens.The antenna adopts a dual-arm planar Archimedes spiral antenna as the radiation unit.A metal ring is loaded on the periphery of the radiation arms to improve the VSWR,and an exponential gradient microstrip balun is used as the feeding structure.The antenna utilizes a dielectric lens on the top and a metal truncated cone-shaped reflective backplate at the bottom to achieve unidirectional radiation,which can adjust the beam shape and improve the radiation gain.The height and the diameter of the antenna assembled with a cylindrical radome is 87.53 mm and 46.50 mm,respectively.The simulated results show that the return loss of the antenna is less than-10 dB in the frequency band of 3-12 GHz,and the radiation pattern presents good directional characteristics.The measured results are basically consistent with the simulated results.