| With the wide application of technologies such as radio,wireless communication and wireless local area network,the electromagnetic energy of various frequencies in free space is increasing.It is a research hotspot of many scholars and experts to collect and reuse these RF energy.The rectenna is a key component in the RF energy harvesting system.It is mainly composed of a receiving antenna and a rectifying circuit.The receiving antenna collects electromagnetic energy in free space.The rectifying circuit converts the collected electromagnetic energy into direct-use DC energy,to power some low-power devices.The electromagnetic energy distributed in space has the characteristics of low power density,multi-band,multi-polarization,etc.Therefore,this paper aims to design a wideband circularly polarized receiving antenna and a high-efficiency wideband rectifying circuit.Details are as follows:1)A wideband circularly polarized antenna for RF energy harvesting is proposed.The antenna adopts two perpendicularly rectangular dipole structures.The dipole arms of the same face are connected by a three-quarter ring delay line,to realize circularly polarized radiation;Adding two L-shaped branch lines and cutting the corners in each rectangular effectively widen the impedance bandwidth and the axial ratio bandwidth of the antenna.2)Based on a double stub matching network,a broadband rectifier circuit is proposed.The 1.78-2.48 GHz wideband rectifier circuit is realized by paralleling two double stub matching networks.When the input power is-5d Bm,0d Bm and 5d Bm,the conversion efficiency in the working frequency band can reach 35%,45%,50% respectively.3)Based on a single stub matching network,a broadband rectifier circuit is proposed.The 1.82-2.48 GHz wideband rectifier circuit is realized by paralleling two single stub matching networks.When the input power is-5d Bm,0d Bm and 5d Bm,the conversion efficiency in the working frequency band can reach 39.8%,50.9%,60.4% respectively. |
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