一种基于缝隙结构的小型双频段射频能量接收天线

A Small Dual-frequency Antenna based on Slot Structure for Wireless Energy Collection

随着超低功耗芯片技术的发展,无线传感器节点的功耗已进入微瓦(μW)级范围,使低功耗传感器利用周围环境中的射频无线能量为自身供电成为可能。提出了一种用于无线传感器节点的小型射频能量接收天线。该天线采用微带缝隙结构,基于缝隙天线设计理论,应用全波电磁场工具对其进行了设计及仿真优化,并获得了该结构谐振点随尺寸变化的一般规律。在常用FR4材料的小尺寸双面PCB板上,通过开槽加载和微带线馈电方法使天线可以同时工作在GSM和ISM两个频段。在1.9 GHz和2.4 GHz频率点上,天线的回波损耗分别为-39.4 dB和-20.8 dB,最大增益分别达到1.4 dBi和2.9 dBi,测试与仿真结果基本吻合。该天线含地平面在内的尺寸为5 cm×5 cm,实现成本低,可同时接收两个频段的射频能量,有效地扩展了频率适应范围,提高了能量接收效率。

With the technical development of ultra-low power consumption chip technology, the power consumption of wireless sensor node is reduced to a micro-watt（μW） magnitude, so it is possible for the sensor node to power itself by collecting ambient wireless energy. The paper describes a small energy-collec- ting antenna for wireless sensor node. With microstrip slot structure and based on the slot antenna theory, this antenna is simulated and optimized by full-wave electromagnetic field tools, and the general rules for the relations between resonance frequency and size are acquired. By slotting and feeding microstrip on the small FR4 PCB, the antenna can work at the dual-frequency of GSM and ISM, and has the return losses of -31.6 dB and -20.8 dB respectively at 1.9GHz and 2.4 GHz, the maxim gain of the antenna is 1.5 dBi and 2.9 dBi respectively. The measurement results of antenna fairly agree with the simulation results. The antenna including the ground plane is 5 cm×5 cm in size and low in cost. Meanwhile, this antenna can receive RF energy at dual-frequency, thus could effectively expand the frequency range and improve the efficiency of the energy collection.