A compact antenna formed by three concentric split rings for ultra-high frequency(UHF)radio frequency identification(RFID)tag is proposed in this paper.The antenna is composed of two parts,an outer short-circuited rin...A compact antenna formed by three concentric split rings for ultra-high frequency(UHF)radio frequency identification(RFID)tag is proposed in this paper.The antenna is composed of two parts,an outer short-circuited ring modified from a traditional split-ring resonator(SRR)antenna and an inner SRR load,so the antenna can be regarded as a short-circuited ring loaded with SRR.According to the transmission line theory,to conjugate match with the capacitive input-impedance of a tag chip,the length of the short-circuited ring isλg/4 shorter than that of an open-circuited dipole of a traditional SRR antenna,whereλg is the wavelengh of the operating frequency.Hence,the size of the proposed antenna is more compact than that of the traditional SRR antenna.Thereafter,the proposed antenna is simulated and optimized by ANSYS high-frequency structure simulator(HFSS).The impedance,efficiency,and mutual coupling of the fabricated antenna are tested in a reverberation chamber(RC).The results show that the size of the presented antenna is 83%smaller than that of the traditional SRR antenna and the proposed antenna can cover the whole UHF RFID operating frequency band worldwide(840—960 MHz).The measured read range of the tag exhibits maximum values of 45 cm in free space and 37 cm under dense tag environment.展开更多
目的应用CiteSpace和VOSviewer软件对蛇咬伤领域的研究现状、热点及趋势进行可视化分析。方法采用文献计量学方法从Web of Science核心库中收集相关文献,并使用CiteSpace和VOSviewer进行数据可视化和分析。结果通过446篇相关文献研究,...目的应用CiteSpace和VOSviewer软件对蛇咬伤领域的研究现状、热点及趋势进行可视化分析。方法采用文献计量学方法从Web of Science核心库中收集相关文献,并使用CiteSpace和VOSviewer进行数据可视化和分析。结果通过446篇相关文献研究,发现蛇咬伤的临床研究主要集中在蛇咬伤的治疗与护理、预防与控制、诊断与治疗以及蛇毒成分。其中,蛇毒成分的研究最为热门,而蛇咬伤患者的临床治疗与护理管理则是重点研究方向。结论本研究系统分析了蛇咬伤临床研究的趋势和热点,为今后蛇咬伤的临床决策和急诊医学研究提供进一步参考。展开更多
文摘A compact antenna formed by three concentric split rings for ultra-high frequency(UHF)radio frequency identification(RFID)tag is proposed in this paper.The antenna is composed of two parts,an outer short-circuited ring modified from a traditional split-ring resonator(SRR)antenna and an inner SRR load,so the antenna can be regarded as a short-circuited ring loaded with SRR.According to the transmission line theory,to conjugate match with the capacitive input-impedance of a tag chip,the length of the short-circuited ring isλg/4 shorter than that of an open-circuited dipole of a traditional SRR antenna,whereλg is the wavelengh of the operating frequency.Hence,the size of the proposed antenna is more compact than that of the traditional SRR antenna.Thereafter,the proposed antenna is simulated and optimized by ANSYS high-frequency structure simulator(HFSS).The impedance,efficiency,and mutual coupling of the fabricated antenna are tested in a reverberation chamber(RC).The results show that the size of the presented antenna is 83%smaller than that of the traditional SRR antenna and the proposed antenna can cover the whole UHF RFID operating frequency band worldwide(840—960 MHz).The measured read range of the tag exhibits maximum values of 45 cm in free space and 37 cm under dense tag environment.
文摘目的应用CiteSpace和VOSviewer软件对蛇咬伤领域的研究现状、热点及趋势进行可视化分析。方法采用文献计量学方法从Web of Science核心库中收集相关文献,并使用CiteSpace和VOSviewer进行数据可视化和分析。结果通过446篇相关文献研究,发现蛇咬伤的临床研究主要集中在蛇咬伤的治疗与护理、预防与控制、诊断与治疗以及蛇毒成分。其中,蛇毒成分的研究最为热门,而蛇咬伤患者的临床治疗与护理管理则是重点研究方向。结论本研究系统分析了蛇咬伤临床研究的趋势和热点,为今后蛇咬伤的临床决策和急诊医学研究提供进一步参考。