无线局域网络信号WLAN(Wireless Local Area Networks)的热点覆盖问题是网络工程中的难题,其难的原因有两点:一是WLAN信号工作于2.4GHz的高频段,信号绕射和穿透建筑材料的能力很差,每经过一层材料,信号衰减很严重;二是无线AP发射功率很...无线局域网络信号WLAN(Wireless Local Area Networks)的热点覆盖问题是网络工程中的难题,其难的原因有两点:一是WLAN信号工作于2.4GHz的高频段,信号绕射和穿透建筑材料的能力很差,每经过一层材料,信号衰减很严重;二是无线AP发射功率很小,受电脑终端发射功率也很小的牵制,又不能随意增大发射功率,覆盖范围很有限.所以实现无线网络信号的无盲点、无缝隙覆盖工程难度很大.通过实验,研究分析了2.4GHz频率的传播特性,结合邻频之间的重叠与非重叠干扰问题的因素,围绕大学校园的具体建筑特点,就无线网络信号的热点覆盖问题给出一种简单、高效、省时、省料的切实可行的施工方案,通过这个具体的案例,可以总结出WLAN信号覆盖的新思路.展开更多
Topological photonics provides a new opportunity for the examination of novel topological properties of matter,in which the energy band theory and ideas in topology are utilized to manipulate the propagation of photon...Topological photonics provides a new opportunity for the examination of novel topological properties of matter,in which the energy band theory and ideas in topology are utilized to manipulate the propagation of photons.Since the discovery of topological insulators in condensed matter,researchers have studied similar topological effects in photonics.Topological photonics can lead to materials that support the robust unidirectional propagation of light without back reflections.This ideal transport property is unprecedented in traditional optics and may lead to radical changes in integrated optical devices.In this review,we present the exciting developments of topological photonics and focus on several prominent milestones of topological phases in photonics,such as topological insulators,topological semimetals,and higher-order topological phases.We conclude with the prospect of novel topological effects and their applications in topological photonics.展开更多
文摘无线局域网络信号WLAN(Wireless Local Area Networks)的热点覆盖问题是网络工程中的难题,其难的原因有两点:一是WLAN信号工作于2.4GHz的高频段,信号绕射和穿透建筑材料的能力很差,每经过一层材料,信号衰减很严重;二是无线AP发射功率很小,受电脑终端发射功率也很小的牵制,又不能随意增大发射功率,覆盖范围很有限.所以实现无线网络信号的无盲点、无缝隙覆盖工程难度很大.通过实验,研究分析了2.4GHz频率的传播特性,结合邻频之间的重叠与非重叠干扰问题的因素,围绕大学校园的具体建筑特点,就无线网络信号的热点覆盖问题给出一种简单、高效、省时、省料的切实可行的施工方案,通过这个具体的案例,可以总结出WLAN信号覆盖的新思路.
基金the National Key Research and Development Program of China(Nos.2016YFA0301102 and 2017YFA0303800)the National Natural ScienceFund for Distinguished Young Scholars(No.11925403)+1 种基金the NationalNatural Science Foundation of China(Nos.11974193,91856101,and11774186)the Natural Science Foundation of Tianjin for DistinguishedYoung Scientists(No.18JCJQJC45700)。
文摘Topological photonics provides a new opportunity for the examination of novel topological properties of matter,in which the energy band theory and ideas in topology are utilized to manipulate the propagation of photons.Since the discovery of topological insulators in condensed matter,researchers have studied similar topological effects in photonics.Topological photonics can lead to materials that support the robust unidirectional propagation of light without back reflections.This ideal transport property is unprecedented in traditional optics and may lead to radical changes in integrated optical devices.In this review,we present the exciting developments of topological photonics and focus on several prominent milestones of topological phases in photonics,such as topological insulators,topological semimetals,and higher-order topological phases.We conclude with the prospect of novel topological effects and their applications in topological photonics.
