平面接收阵列天线的反射测量

在微波无线能量传输(MWPT)中,接收阵列天线通常采用分布式整流将接收到的微波能量转换为直流能量,其天线单元的最大入射功率决定了整流电路的设计.然而,接收阵列天线边缘单元所能接收到的功率小,使所接整流电路阻抗发生变化,与阵列天线单元失配造成较大的反射.首先从理论上论证了随着接收天线单元输入功率的变化,接收阵列天线边缘单元的反射大于中间单元.然后设计了一个低剖面(0.05λ2)、高定向性(12.5 dBi)、高前后比(27 dB)的微带准八木天线作为探头.最后测量了10×10平面接收阵列天线连接整流电路时的反射和入射功率分布图,并计算得到反射因子(反射因子定义为到达接收阵列天线单元表面上的反射功率和入射功率的比值)分布图.实验结果与理论分析一致,该实验为提高MWPT中接收端的效率起到指导作用.

Reflectionmeasurement of planar reception antenna array

In the microwave wireless energy transmission(MWPT),in mostly,the received microwave energy was transformed into direct circuit(DC) energy by adopting distributed rectification.The maximal incident power on the receiver array antenna units determines the rectifier circuit design.However,the power received by the cell at the edge of the array antenna array is smaller than others,which resulting in a change to the impedance of Rectifier circuit,mismatchingwith array antenna cells also cause a larger reflection.In this paper,theoretically,The reflection of the receiving antenna array edge unit is greater than that of the intermediate unit,caused by the changes of the input power on the receiving antenna units and the mismatch between the planar antenna array and the rectifier circuits are presented.Then a low-profile (0.05λ2),high directivity (12.5 dBi),high front and rear ratio (27 dB) Quasi Yagi antenna were designed as probes.The reflection power distribution and the incident power distribution of the 10 × 10planar array antenna is measured,moreover the reflection factor (the reflection factor is defined as the ratio of the reflected power to the incident power reached in the surface of the reception antenna unit) is calculated.The experimental results is consistent with the theoretical analysis,which plays a guiding role in improving the efficiency of receiver in MWPT.