Electromagnetic field generators based on circular ring resonators,whose perimeters are integer times of equivalent wavelength,are well known to have attractive potential for producing radio vortexes carrying orbital ...Electromagnetic field generators based on circular ring resonators,whose perimeters are integer times of equivalent wavelength,are well known to have attractive potential for producing radio vortexes carrying orbital angular momentum(OAM).We study the radiation characteristics of the generators based on radiation vector and antenna array theory.The behaviors of radiation patterns,field intensity and phase distribution are investigated in detail,and show classical features of OAM beams.The evolution of the generators performance versus the OAM state is also analyzed.The proposed generators can be realized by all kinds of microwave transmission lines,verified by two different prototypes.The discussions and conclusions drawn in this study are useful and meaningful for the radio OAM generator design.展开更多
Based on two-step coordinate transformation along the radial direction, an optical device with three functions is proposed. The proposed device functions as a transparent device, a vision-enabling internal cloak, and ...Based on two-step coordinate transformation along the radial direction, an optical device with three functions is proposed. The proposed device functions as a transparent device, a vision-enabling internal cloak, and a movement-allowing external cloak. The general expressions of material parameters for the optical device are determined, and each function of the device is confirmed using full-wave simulation. The effect of material loss on device performance is also investigated. Future applications for the proposed device include antenna protection and military stealth.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61461052the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20135301110003+1 种基金the Seventh of Yunnan University Graduate Student Scientific Research Project under Grant No ynuy201443the Doctoral Award for the Academic Newcomers(2014)of Yunnan Province under Grant No C6155501
文摘Electromagnetic field generators based on circular ring resonators,whose perimeters are integer times of equivalent wavelength,are well known to have attractive potential for producing radio vortexes carrying orbital angular momentum(OAM).We study the radiation characteristics of the generators based on radiation vector and antenna array theory.The behaviors of radiation patterns,field intensity and phase distribution are investigated in detail,and show classical features of OAM beams.The evolution of the generators performance versus the OAM state is also analyzed.The proposed generators can be realized by all kinds of microwave transmission lines,verified by two different prototypes.The discussions and conclusions drawn in this study are useful and meaningful for the radio OAM generator design.
基金supported by the National Natural Science Foundations of China(Nos.61161007 and 61261002)the Scientific Research Fund Major Project of the Education Bureau of Yunnan Province(No.ZD2011003)+1 种基金the Natural Science Foundation of Yunnan Province(No.2011FB018)the Doctoral Program of Higher Education(No.20125301120009)
文摘Based on two-step coordinate transformation along the radial direction, an optical device with three functions is proposed. The proposed device functions as a transparent device, a vision-enabling internal cloak, and a movement-allowing external cloak. The general expressions of material parameters for the optical device are determined, and each function of the device is confirmed using full-wave simulation. The effect of material loss on device performance is also investigated. Future applications for the proposed device include antenna protection and military stealth.
