设计了一款具有陷波功能的天线,用来提高射频能量收集系统的能量采集效率。由于射频能量收集系统后端整流电路中二极管具有非线性效应,在整流过程中会产生高次谐波。产生的高次谐波会反向传输至天线并向外辐射,从而造成能量损耗,降低整个射频能量收集系统的效率。为了抑制高次谐波,通常可在整流二极管前加载带通滤波器。但滤波器的使用会增加系统尺寸并引入额外插损。针对此问题,将该谐波抑制天线与设计的2.45 GHz整流电路相连接,可制成具有谐波抑制的整流天线。对该谐波抑制整流天线进行实测,并与另一无谐波抑制的整流天线进行了对比。实测结果表明:具有谐波抑制功能的整流天线比无谐波抑制的效率高4.1%。由此可知,在射频能量收集系统的应用中,具有谐波抑制功能的陷波天线作为接收天线,可提高系统能量收集效率;同时,由于在整流电路中免去了滤波器,可实现整个能量收集系统的小型化。

An antenna with a notch function is designed to improve the energy harvesting efficiency of the radio frequency (RF) energy harvesting system. Because the diode in the rectifier circuit of the RF energy collection system has a nonlinear effect, high-order harmonics are generated during the rectification process. The generated higher harmonics will be transmitted to the antenna in the reverse direction and radiate outward, thereby causing energy loss and reducing the efficiency of the entire RF energy collection system. In order to suppress higher harmonics, a band-pass filter can usually be loaded in front of the rectifier diode. However, the use of filters will increase the size of the system and introduce additional insertion loss. In response to this problem, the harmonic suppression antenna is connected with the designed 2.45 GHz rectifier circuit to make a rectifier antenna with harmonic suppression. The harmonic suppression rectifier antenna is measured and compared with another rectifier antenna without harmonic suppression. The measured results show that the rectifier antenna with harmonic suppression function is 4.1% more efficient than without harmonic suppression. It can be seen that in the application of the RF energy collection system, with harmonic suppression function designed as the receiving antenna in this work can improve the energy collection efficiency of the system; at the same time, because the filter is eliminated in the rectifier circuit, the entire energy harvesting system can be miniaturized.

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