为了尽可能高效地吸收和整流分布在周围自然空间中的射频能量，提出了一种 工作在 GSM-1800 和 UMTS-2100 频段的双频射频能量收集系统的设计方法: 系统的接收 天线部分采用结构简单的宽带八木天线; 系统的整流电路部分为应用于低输入功率的双 频整流电路; 整流电路的匹配电路部分使用微带线匹配，没有使用任何分立贴片元件，以 保证整流电路在高频时稳定的性能，同时降低电路实际加工制作的复杂度． 最后对系统整 体进行了实验室和室外环境的联合测试． 实测结果表明，文中提出的双频无线射频能量收 集系统在 －20 ～ －5dBm 低输入功率下，能够在 1． 8GHz 和 2． 1GHz 频段获得良好的双频 匹配，并且在 －5dBm 输入功率下获 45%的整流效率，且具有从环境中收集射频能量并输 出一定直流电压的能力．

In order to absorb and rectify as efficiently as possible the radio frequency energy distributed in the sur- rounding environment，this paper proposes a dual-band ＲF energy harvesting system operating in GSM1800 and UMTS2100 frequency bands． The receiving antenna of this system adopts a planar broadband yagi antenna，which has compact structure，high measured average gain and stable directional radiation pattern in the working frequency bands． In the low input power circumstance from －20 dBm to －5 dBm，the rectifying circuit of this system can achieve good dual-band resonance at 1. 8GHz and 2. 1GHz． The maximum rectification efficiency can reach 45% in －5dBm． Finally，the overall system has been tested in the laboratory and ambience． The results show that the proposed dual-band system can achieve 45% ＲF-DC conversion efficiency in －5 dBm in the laboratory measure- ment，and the proposed system is qualified for harvesting ＲF energy and achieves a certain amount of DC power on the resistance load in ambient environment．