基于双层人工表面等离激元的高扫描率漏波天线

A High-Scanning-Rate Leaky-Wave Antenna Based on Double Layer Spoof Surface Plasmon Polaritons

针对传统人工表面等离激元(SSPPs)漏波天线扫描速率低的现象,提出了一种新型双层SSPPs单元,并基于此实现了拥有高扫描率特征的漏波天线。所提出的双层SSPPs单元由具有“H”形的顶层SSPPs单元和具有“I”形的底层SSPPs单元组成。所提出的单元通过分别控制顶层和底层SSPPs单元的色散特性,能够实现对色散曲线的截止频率和斜率的独立控制。所提出的漏波天线的辐射是通过对顶层的“H”形单元进行正弦表面阻抗调制来实现的。由于底层“I”形的SSPPs单元的存在,引入了强色散特性,提高了周期相移的增长速率,从而实现了高扫描速率。此外,通过在周期辐射结构上引入短路枝节,该漏波天线的开阻带(OSB)现象被几乎完全抑制。通过对所提出的漏波天线的原型进行仿真、加工和测量,该漏波天线能够在8.8~10.8 GHz之间的窄频段实现从后向-63°到正向63°的大角度连续扫描。测试结果与仿真结构一致证明了提出双层SSPPs单元与设计理论的正确性。

With the scanning rate of traditional spoof surface plasmon polaritons(SSPPs)leaky-wave antenna being low,a novel double layer SSPPs element is proposed,and a leaky-wave antenna with high scanning rate is realized on the basis of this.The proposed double layer SSPPs element consists of a top SSPPs element with a“H”cell and a bottom SSPPs element with a“I”element.The proposed element is characterized by independently controlling the cut-off frequency and slope of the dispersion curve,realizing the cut-off frequency and slope of dispersion curve to be controlled independently by controlling the dispersion property of the top and bottom SSPPs elements respectively.The radiation of the proposed leakywave antenna is realized by sinusoidal surface impedance modulation of the“H”elements on the top layer.Due to the existence of the bottom“I”SSPPs elements,the strong dispersion property is introduced to improve the growth rate of period phase shift,thus achieving the high scanning rate.In addition,the open stopband(OSB)phenomenon of the leaky-wave antenna is almost completely suppressed by introducing short open-ended stubs in the periodic radiation structure.The prototype of the proposed leaky-wave an tenna is simulated,machined and measured.The leaky-wave antenna is capable of achieving continuous wide-angle scanning from-63°to 63°at a narrow band between 8.8 GHz and 10.8 GHz.The consistency between the experimental and the simulated results proves the correctness of the proposed double-layer SSPPs element and the design theory.