具有谐波抑制功能的宽带圆极化宽缝天线

针对微波无线输能系统中接收天线质量轻、体积小、剖面低、易与微波电路集成的特点，设计了一款新型的具有谐波抑制功能的宽带圆极化宽缝接收天线。通过在长方形缝隙中添加末端具有圆形贴片的交叉结构实现圆极化性能，添加切角结构展宽圆极化带宽。在馈线上添加具有一定长度的开路支节，配合使用缺陷地结构共同实现谐波抑制功能。研究并测试了天线的反射系数、轴比、增益以及远场辐射方向图，仿真与实测基本吻合。仿真结果显示，该天线很好地抑制了基频5.8 GHz的二次谐波和三次谐波，在4.5~6.2 GHz的范围内S11<-10 dB，相对阻抗带宽31.8%；基频5.8 GHz处的轴比AR=1.3 dB，在频率范围4.2~6.15 GHz内轴比AR<3 dB，相对轴比带宽37.7%；基频5.8 GHz仿真增益6.7 dB。

Wideband circularly polarized slot antenna with harmonic suppression

In the microwave power transmission system, the receiving antenna has preferred to meet the requirements of light weight, small size, low profile, and easy integration with microwave circuits. A new type of wideband circularly polarized wide slot antenna with harmonic suppression is designed that can meet these requirements. The circular polarization performance is achieved by adding a cross structure having a circular patch at the end in the rectangular slot, and the chamfering structure broadens the circular polarization bandwidth. Adding an open section with a certain length on the feed-line and DGS(Defected Ground Structure) structure supports to achieve the harmonic suppression function. Considerable efforts have been devoted to study and test the reflection coefficient, axial ratio, gain and far field radiation pattern. The simulation results are in a good agreement with the measured results. The simulation results show that the antenna works well to suppress the second and third harmonics of the fundamental frequency at 5.8 GHz. The measured bandwidths for the relative impedance(S11<-10 dB) are 31.8%(from 4.5 to 6.2 GHz) and axial ratio (AR<3 dB) 37.7%(from 4.2 to 6.15 GHz), respectively, and the antenna has a stable radiation pattern and a gain of 6.7 dB at a center frequency of 5.8 GHz.