Undoped and copper(Cu)doped zinc oxide(Zn_(1-x)Cu_(x)O,where x=0-0.065)nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering technique.The aim of this work is to investigate t...Undoped and copper(Cu)doped zinc oxide(Zn_(1-x)Cu_(x)O,where x=0-0.065)nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering technique.The aim of this work is to investigate the crystal structure of ZnO and Cu doped ZnO thin films and also study the effect of Cu doping on optical band gap of ZnO thin films.The identification and confirmation of the crystallinity,film thickness and surface morphology of the nano range thin films are confirmed by using X-ray diffractometer(XRD),scanning electron microscope and atomic force microscope.The XRD peak at a diffractive angle of 34.44°and Miller indices at(002)confirms the ZnO thin films.Crystallite size of undoped ZnO thin films is 27 nm and decreases from 27 nm to 22 nm with increasing the atomic fraction of Cu(x_(Cu))in the ZnO thin films from 0 to 6.5%respectively,which is calculated from XRD(002)peaks.The different bonding information of all deposited films was investigated by Fourier transform infrared spectrometer in the range of wave number between 400 cm^(-1) to 4000 cm^(-1).Optical band gap energy of all deposited thin films was analyzed by ultraviolet visible spectrophotometer,which varies from 3.35 eV to 3.19 eV with the increase of x_(Cu) from 0 to 6.5%respectively.Urbach energy of the deposited thin films increases from 115 meV to 228 meV with the increase of x_(Cu) from 0 to 6.5% respectively.展开更多
With the rapid development of the mobile internet and the massive deployment of the Internet of Things, mobile devices, including both the consumer electronics and the sensors, become hungrier for the energy than ever...With the rapid development of the mobile internet and the massive deployment of the Internet of Things, mobile devices, including both the consumer electronics and the sensors, become hungrier for the energy than ever before. Conventional cable based charging largely restrict the movement of the mobile devices. Wireless charging hence emerges as an essential technique for enabling our ultimate goal of charging anytime and anywhere. By efficiently exploiting the legacy of the existing communication infrastructure, we propose a nov- el data and energy integrated network （DEIN） in order to re- alise the radio frequency （RF） based wireless charging with- out degrading the information transmission. In this treatise, we focus on the implementation of the DEIN in both the theoretical and practical aspects, concerning the transceiver architecture design and the rectifier circuit design. Furthermore, we also present a Wi-Fi based testbed for demonstrating the availability of the RF based wireless charging.展开更多
The abundance of telecommunications systems makes it possible to have somewhat significant quantity of radiofrequency energy in the environment. This energy can be recycled to power ultra-low-power devices such as Wir...The abundance of telecommunications systems makes it possible to have somewhat significant quantity of radiofrequency energy in the environment. This energy can be recycled to power ultra-low-power devices such as Wireless Sensor Network (WSN). In this paper, the performance of a miniature RF/DC converter is evaluated in order to enslave a WSN’s per-formance to the amount of the recovered energy. More precisely, a highly sensitive and efficient rectifier is designed to achieve optimum performance in the GSM band. The design method relies on a judicious choice of the rectifying diode which is the basis of most losses in a rectifying antenna (rectenna). Optimum performance is achieved by using the gradient method search proposed in the Advanced Design System (ADS) software. A rectifier based on Schottky diodes HSMS 2850 used in a voltage doubler topology is thus obtained. A maximum RF/DC conversion efficiency of 36% is reached for an RF input power level of 10 dBm. An energy budget of a sensor node in a WSN having an equitable distribution of network loads is then defined and used to evaluate the performance of the WSN regarding the distance at which the Base Station (BS) can be located. The Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is used for this purpose. The distance separating the WSN from the BS is used as the enslavement parameter. Our analysis shows that increasing the duration of each round results in an increase in the range of the WSN. As an example, a network with 100 nodes distributed over an area of may be located at 1.3 km from the base station when each node of the WSN must perform measurements every 1 min.展开更多
传统桥式全波RF-DC变换电路在设计过程中忽略了二极管导通损耗,从而影响系统效率。采用了E类零电压开关(Zero Voltage Switching,ZVS)RF-DC变换电路,设计了谐振频率为8 MHz,输入功率为1.21 W的无线电力传输系统接收模块。并利用multisi...传统桥式全波RF-DC变换电路在设计过程中忽略了二极管导通损耗,从而影响系统效率。采用了E类零电压开关(Zero Voltage Switching,ZVS)RF-DC变换电路,设计了谐振频率为8 MHz,输入功率为1.21 W的无线电力传输系统接收模块。并利用multisim软件进行了仿真。结果表明,该设计方法降低了二极管导通损耗,有效避免了传统桥式全波RF-DC变换电路存在的缺陷,效率可达92%。展开更多
基金Maulana Azad National Fellowship(MANF)Scheme of University Grants Commission,New Delhi,India。
文摘Undoped and copper(Cu)doped zinc oxide(Zn_(1-x)Cu_(x)O,where x=0-0.065)nano crystal thin films have been deposited on glass substrate via RF/DC reactive co-sputtering technique.The aim of this work is to investigate the crystal structure of ZnO and Cu doped ZnO thin films and also study the effect of Cu doping on optical band gap of ZnO thin films.The identification and confirmation of the crystallinity,film thickness and surface morphology of the nano range thin films are confirmed by using X-ray diffractometer(XRD),scanning electron microscope and atomic force microscope.The XRD peak at a diffractive angle of 34.44°and Miller indices at(002)confirms the ZnO thin films.Crystallite size of undoped ZnO thin films is 27 nm and decreases from 27 nm to 22 nm with increasing the atomic fraction of Cu(x_(Cu))in the ZnO thin films from 0 to 6.5%respectively,which is calculated from XRD(002)peaks.The different bonding information of all deposited films was investigated by Fourier transform infrared spectrometer in the range of wave number between 400 cm^(-1) to 4000 cm^(-1).Optical band gap energy of all deposited thin films was analyzed by ultraviolet visible spectrophotometer,which varies from 3.35 eV to 3.19 eV with the increase of x_(Cu) from 0 to 6.5%respectively.Urbach energy of the deposited thin films increases from 115 meV to 228 meV with the increase of x_(Cu) from 0 to 6.5% respectively.
基金supported by University of Electronic Science and Technology of China under Grant No.ZYGX2016KYQD103
文摘With the rapid development of the mobile internet and the massive deployment of the Internet of Things, mobile devices, including both the consumer electronics and the sensors, become hungrier for the energy than ever before. Conventional cable based charging largely restrict the movement of the mobile devices. Wireless charging hence emerges as an essential technique for enabling our ultimate goal of charging anytime and anywhere. By efficiently exploiting the legacy of the existing communication infrastructure, we propose a nov- el data and energy integrated network （DEIN） in order to re- alise the radio frequency （RF） based wireless charging with- out degrading the information transmission. In this treatise, we focus on the implementation of the DEIN in both the theoretical and practical aspects, concerning the transceiver architecture design and the rectifier circuit design. Furthermore, we also present a Wi-Fi based testbed for demonstrating the availability of the RF based wireless charging.
文摘The abundance of telecommunications systems makes it possible to have somewhat significant quantity of radiofrequency energy in the environment. This energy can be recycled to power ultra-low-power devices such as Wireless Sensor Network (WSN). In this paper, the performance of a miniature RF/DC converter is evaluated in order to enslave a WSN’s per-formance to the amount of the recovered energy. More precisely, a highly sensitive and efficient rectifier is designed to achieve optimum performance in the GSM band. The design method relies on a judicious choice of the rectifying diode which is the basis of most losses in a rectifying antenna (rectenna). Optimum performance is achieved by using the gradient method search proposed in the Advanced Design System (ADS) software. A rectifier based on Schottky diodes HSMS 2850 used in a voltage doubler topology is thus obtained. A maximum RF/DC conversion efficiency of 36% is reached for an RF input power level of 10 dBm. An energy budget of a sensor node in a WSN having an equitable distribution of network loads is then defined and used to evaluate the performance of the WSN regarding the distance at which the Base Station (BS) can be located. The Low Energy Adaptive Clustering Hierarchy (LEACH) protocol is used for this purpose. The distance separating the WSN from the BS is used as the enslavement parameter. Our analysis shows that increasing the duration of each round results in an increase in the range of the WSN. As an example, a network with 100 nodes distributed over an area of may be located at 1.3 km from the base station when each node of the WSN must perform measurements every 1 min.
文摘传统桥式全波RF-DC变换电路在设计过程中忽略了二极管导通损耗,从而影响系统效率。采用了E类零电压开关(Zero Voltage Switching,ZVS)RF-DC变换电路,设计了谐振频率为8 MHz,输入功率为1.21 W的无线电力传输系统接收模块。并利用multisim软件进行了仿真。结果表明,该设计方法降低了二极管导通损耗,有效避免了传统桥式全波RF-DC变换电路存在的缺陷,效率可达92%。
