Thermal rectification is an exotic thermal transport phenomenon,an analog to electrical rectification,in which heat flux along one direction is larger than that in the other direction and is of significant interest in...Thermal rectification is an exotic thermal transport phenomenon,an analog to electrical rectification,in which heat flux along one direction is larger than that in the other direction and is of significant interest in electronic device applications.However,achieving high thermal rectification efficiency or rectification ratio is still a scientific challenge.In this work,we performed a systematic simulation of thermal rectification by considering both efforts of thermal conductivity asymmetry and geometrical asymmetry in a multi-segment thermal rectifier.It is found that the high asymmetry of thermal conductivity and the asymmetry of the geometric structure of multi-segment thermal rectifiers can significantly enhance the thermal rectification,and the combination of both thermal conductivity asymmetry and geometrical asymmetry can further improve thermal rectification efficiency.This work suggests a possible way for improving thermal rectification devices by asymmetry engineering.展开更多
A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to...A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to the nonlinear characteristics of the diodes, a new band-stop structure is introduced to reduce the imaginary part impedance and suppress harmonics. A novel structure with double branches and an optimized λ/4 microstrip line is proposed to realize the power division ratio adjustment by the input power automatically. The proposed two branches can satisfy the two cases with input power of-20 dBm to 0 dBm and 0 dBm to 15 dBm, respectively. Here, dBm = 10 log(P mW), and P represents power. An impedance compression network(ICN) is correspondingly designed to maintain the input impedance stability over the wide input power range. A rectifier that works at 2.45 GHz is implemented. The measured results show that the highest efficiency can reach 51.5% at the output power of 0 dBm and higher than 40% at the input power of-5 dBm to 12 dBm.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.12274355)Xiamen University Malaysia Research Fund(Grant Nos.XMUMRF/2022C9/IORI/003 and XMUMRF/2022-C10/IORI/004)。
文摘Thermal rectification is an exotic thermal transport phenomenon,an analog to electrical rectification,in which heat flux along one direction is larger than that in the other direction and is of significant interest in electronic device applications.However,achieving high thermal rectification efficiency or rectification ratio is still a scientific challenge.In this work,we performed a systematic simulation of thermal rectification by considering both efforts of thermal conductivity asymmetry and geometrical asymmetry in a multi-segment thermal rectifier.It is found that the high asymmetry of thermal conductivity and the asymmetry of the geometric structure of multi-segment thermal rectifiers can significantly enhance the thermal rectification,and the combination of both thermal conductivity asymmetry and geometrical asymmetry can further improve thermal rectification efficiency.This work suggests a possible way for improving thermal rectification devices by asymmetry engineering.
基金Key Laboratory of Chinese Academy of Sciences Foundation,China(No. 20190918)。
文摘A rectifier circuit for wireless energy harvesting(WEH) with a wide input power range is proposed in this paper. We build up accurate models of the diodes to improve the accuracy of the design of the rectifier. Due to the nonlinear characteristics of the diodes, a new band-stop structure is introduced to reduce the imaginary part impedance and suppress harmonics. A novel structure with double branches and an optimized λ/4 microstrip line is proposed to realize the power division ratio adjustment by the input power automatically. The proposed two branches can satisfy the two cases with input power of-20 dBm to 0 dBm and 0 dBm to 15 dBm, respectively. Here, dBm = 10 log(P mW), and P represents power. An impedance compression network(ICN) is correspondingly designed to maintain the input impedance stability over the wide input power range. A rectifier that works at 2.45 GHz is implemented. The measured results show that the highest efficiency can reach 51.5% at the output power of 0 dBm and higher than 40% at the input power of-5 dBm to 12 dBm.
