Design And Research Of High Efficiency Rectifier With Wide Dynamic Range For Wireless Power Transmission

Wireless Power Transmission(WPT)technology can transfer power to receiver without using traditional connection wire.Microwave Power Transmission(MPT)is one of the most widely used method of WPT,which featrues merits such as wide transmission range,high transmission power level and so on.Rectifier is one of the key components of WPT system,which can transfer received microwave power into DC energy for using.However,due to the nonlinerty of rectifying diode,the dynamic range of rectifier is limited which is critical for practical application.Thus,in this work,multiple methods of rectifier designing is proposed to improve the dynamic range of rectifier.(1)A high-efficiency rectifier with wide input power range based on power recycling is proposed.In the proposed topology,two output ports of the coupler are connected with two sub-rectifiers dealing with higher power level(main branches),while the isolation port is connected with the sub-rectifier dealing with lower power level(power recycling branch).By using the branch-line coupler,the power reflected from the two main branches can be efficiently transmitted to the power recycling branch.Consequently,the power can be reused and thus the RF-dc conversion efficiency can be improved.In this way,the rectifier can maintain high efficiency in a wide input power range.Theoretical analysis and performance comparison are carried out,which show that the proposed topology features recycling ability within a wide input power range.For validation,a rectifier working at 2.45 GHz is implemented and compared to other designs.The measured efficiency remains over 50% from 8.5 to 32.5 dBm,indicating that high efficiency can be obtained within wide input power range.(2)In this paper,a single-branch RF rectifier utilizing integrated impedance compression network(IICN)is proposed.The circuit consists of a matching network,a rectifying circuit with the IICN and a dc-pass filter.Different from the previous reported resistance/impedance compression networks which can only work with dual-branch topology,the IICN connects two diodes in parallel in a single-branch.The nonlinear variation of the diode impedances is reduced when the input power varies owing to the ICN.Thus,the matching performance of the rectifier at wide input power range is improved without degrading the conversion efficiency.The proposed IICN help the rectifier to maintain high efficiency within a wider input power range via a simpler configuration than the previous reported resistive/ impedance compression networks,which results in size reduction and lower circuit complexity.Theoretical analysis and simulation of the IICN are carried out.A prototype operating at 2.45 GHz is optimized,fabricated and measured.Good agreement can be found between simulation and measurement.(3)Reserch on rectifier with wide input power range based on rectifying diode voltage modulation.Firstly,at this work,a rectifying diode volage modulation method is introduced to control the maximum conversion efficiency corresponding input power of the circuit by ultizing a groundline which is connected to the diode.Secondly,a modulation network is designed to improve the input power range of the circuit,which is consisted of two parallel diodes connected to groundlines with differnet length.In addition,the network enable that the circuit maintain high efficiency in different power level.For validation,a rectifier working at 2.45 GHz is implemented and compared to other designs.At last,the possibility of co-design with other technique is discussed.(4)An ultra-wideband rectifier with compact size is designed.The circuit is simply combined of two voltage doubler rectifying structure.In this work,the impedance charactism is analyzed and the harmonic compression capability of voltage doubler is firstly discussed,a compact size matching network is able to realize due to the advantage of the impedance charactism.For validation,a compact size circuit is designed.Both simulation and tested results suggest that the circuit can maintain high conversion efficiency over 50% in a wide bandwidth ranges from 0.1 to 4GHz.