太赫兹通信技术的研究与展望

太赫兹通信是一个极具应用前景的技术,太赫兹波有非常宽的还没分配的频带,并且具有传输速率高、方向性好、安全性高、散射小及穿透性好等许多特性.发展太赫兹通信技术已成为各发达国家研究的热点.该文分析了国内外太赫兹通信的研究情况;以太赫兹通信系统的整体框架,全面地介绍和分析了太赫兹通信的一些关键技术和最新研究成果;同时,对太赫兹的技术发展趋势和应用前景做了展望,提出了太赫兹技术的发展战略.     

基于共振隧穿二极管的近程太赫兹通信技术

太赫兹通信技术是实现6G愿景的关键底层技术之一,针对应用场景选择不同技术路线定制收发系统将是其发展趋势。RTD太赫兹收发模块具有室温、高频率、高灵敏度、易集成等特点,成为太赫兹通信技术领域的新星。通过介绍RTD太赫兹源、探测器及通信系统的工作原理和现状,分析了目前面临的效率及灵敏度提升挑战,并从器件和电路层面探讨和展望了可能解决方案和技术方向,为推动RTD太赫兹通信实用化提出思考。     

太赫兹波探测技术的研究进展

太赫兹波具有优越的特性,使其在物理、化学、生物医学、天文学、材料科学和环境科学等方面有重要的学术和应用价值,以及对国民经济发展、国家安全、反恐和新一代信息科学技术有重大的推动作用,作为太赫兹技术应用的关键器件之一的太赫兹探测器同样到了迅猛的发展。文章介绍了太赫兹探测技术的原理及其应用,并在此基础上分析了太赫兹探测器的最新进展、性能和发展趋势。     

光子太赫兹通信技术

随着无线数据传输速率需求的爆炸式增长,太赫兹频段(0.1~10 THz)以其丰富的频谱资源备受关注。太赫兹光子学的通信技术因具有超宽带、调制效率高、谐波干扰小等技术优势,被公认可以极大地促进数据传输速率向Tbit/s发展。本文以光子太赫兹通信3个方面关键技术的综述分析为基础,包括光子太赫兹通信的收发器件、基带信号处理技术、系统架构与实验验证等,探讨光子太赫兹通信技术的发展趋势,并从宏观与微观尺度展望光子太赫兹通信的潜在应用场景。     

太赫兹无线和有线融合通信技术的研究与展望

随着5G的移动互联及物联网相交织等新型业务的蓬勃发展,对未来通信系统传输容量、传输速度以及误码率等要求愈来愈高。介于毫米波与远红外光之间的太赫兹频段兼有微波和光波的特性,具有低量子能量、大带宽、良好的穿透性。近年来太赫兹通信系统成为研究热点之一,但太赫兹无线通信存在视距传播以及较大路径损耗缺点,太赫兹无线和有线融合传输则兼具两者优点。本文分析了光子太赫兹信号产生、光子太赫兹无线链路传输和光子太赫兹光纤链路传输过程中涉及的器件和技术,重点介绍了太赫兹有线传输的研究现状,并通过基于强度调制直接检测实现1.485 GBaud 350 GHz的1 m太赫兹光纤有线实时传输视频实验,展现了太赫兹有线传输巨大的发展潜力。     

太赫兹探测技术发展与展望

介绍了太赫兹探测技术的发展概况,简要阐述了太赫兹波的探测方法、主要特点、重要的学术应用价值和主要产品,并综述了国内外在太赫兹波领域的研究进展,对未来的发展与应用进行了乐观的展望.     

TEA太赫兹波远程探测数值模拟

太赫兹波具有许多独特的性质,有着广泛的应用 前景。然而,由于水汽对太赫兹波的强烈吸收,使 其在空气中的传输距离十分有限,应用受到了极大限制。TEA现象巧妙的将太赫兹波和光声 信号结合起来, 为太赫兹波的远程探测提供一种有效途径。本文初步探讨了TEA 现象的物理过程及其内在的 物理机制,推 导出了TEA过程的近似理论模型,得到了太赫兹辐射与光声信号幅度增强之间的定量关系。     

实时太赫兹探测与成像技术新进展

图像获取速率和空间分辨率一直是面向应用型太赫兹成像所要解决的关键问题。针对这一问题,学者们基于合成孔径雷达(SAR)成像技术、电磁干涉与压缩感知(CS)等理论,提出了太赫兹合成孔径成像、太赫兹干涉成像和太赫兹压缩感知成像技术,它们在成像速度和空间分辨率等方面具有良好的发展潜力。综述了上述三种方法,总结概括其各自的技术优势以及新近的研究进展。展望了太赫兹成像技术在军事、公共安全领域以及无损探伤等领域的应用前景。     

太赫兹波通信技术研究现状及展望

太赫兹波是介于微波与光波之间的尚未被完全开发利用的频段,基于太赫兹波的通信技术将是下一代通信技术的重点发展方向,并具有广阔的应用前景。首先介绍了太赫兹波通信的基本特性、太赫兹波通信系统的架构组成、以及太赫兹波通信的关键技术,然后对国内外太赫兹波通信的辐射源技术、信号调制技术、信号探测技术以及通信系统的研究进展情况进行了重点阐述,最后对太赫兹通信技术研发过程中面,l盏的困难进行了分析,并对未来太赫兹波通信技术的应用进行了展望。     

探测光波长对太赫兹波电光取样探测技术的影响

由于太赫兹波电光取样探测技术中电光晶体存在的色散关系, 探测光的波长会直接影响到电光取样的探测带宽和效率.由于该色散关系的存在, 不同的电光晶体在电光取样中响应函数不同.本文研究了两种典型的电光晶体-碲化锌和磷化镓晶体的响应函数, 发现在选取的四种探测激光波长内(600 nm、800 nm、1200 nm、1600 nm), 800 nm的探测激光更合适碲化锌晶体, 1200 nm的激光更合适磷化镓晶体.对于不同厚度的晶体, 存在一个最优化的探测激光波长, 使得该晶体的电光响应函数有最宽的带宽.     

太赫兹空间接入技术

随着网络通信的迅速发展,现有通信频段已趋于饱和,为了支撑日益增长的通信速率、频率及带宽需求,使用更高的载波频率将成为通信技术发展的必然。大带宽的太赫兹频段是一个全新的频谱空间,拥有广阔的应用前景,是最具潜力的可行解决方案。现存的相关通信技术仅局限在陆地的微波、毫米波频段,未来网络将扩展至太赫兹频段,不仅能够应对未来超高速率、超低时延无线移动通信网络应用,实现未来的全频谱接入,还可支撑空天地一体化的全覆盖需求。分析了太赫兹链路适用于未来海量遥感数据通信的场景,介绍了基于太赫兹链路的网络接入技术,探讨了太赫兹链路给未来通信带来的机遇与挑战,为太赫兹通信的后续研究发展提供了参考。     

自由空间相干光通信技术及发展

对比了相干探测和直接探测,以及自由空间相干光通信和光纤相干通信,对相干自由空间激光通信系统的特点和关键技术进行了讨论,回顾了近年来国外在自由空间相干光通信领域内开展的有关研究计划.最后对相干光通信技术的应用前景进行了展望.     

第三代移动通信系统无线传输技术的发展

本文简要地介绍了第三代移动通信及其无线传输技术的发展状况。分析比较了当前几种主要的候选无线传输技术，最后对发展我国第三代移动通信提出了几点建议。     

A Review on Terahertz Communications Research

The increasing demand of unoccupied and unregulated bandwidth for wireless communication systems will inevitably lead to the extension of operation frequencies toward the lower THz frequency range. Higher carrier frequencies will allow for fast transmission of huge amounts of data as needed for new emerging applications. Despite the tremendous hurdles that have to be overcome with regard to sources and detectors, circuit and antenna technology and system architecture to realize ultrafast data transmission in a scenario with extensive transmission loss, a new area of research is beginning to form. In this article we give an overview of emerging technologies and system research that might lead to ubiquitous THz communication systems in the future.     

Short-Range Ultra-Broadband Terahertz Communications: Concepts and Perspectives

We propose the concept of ultra-broadband terahertz communication, based on directed non-line-of-sight (NLOS) transmissions. Potential applications of such a system supporting multi-gigabit data rates are given, and put into the context of currently emerging WLANs/WPANs. The technology and propagation constraints serve as boundary conditions for the determination of the required antenna gain to support ultra-broadband communication. Resulting high-gain antenna requirements will necessitate highly directed transmissions. We propose the use of omni-directional dielectric mirrors to support directed NLOS paths. Their performance is investigated with ray-tracing simulations of a terahertz propagation channel in a dynamic office environment, which is calibrated with measured building-material and mirror parameters. We demonstrate that a directed NLOS path scheme will make a terahertz communication system robust to shadowing. Furthermore, we show that dielectric mirrors covering only parts of the walls will significantly enhance the signal coverage in a typical indoor scenario.     

多媒体通信的新发展

本文介绍了各种多媒体通信终端的新标准,对于开发PSTN 多媒体可视电话终端,提出了有关建议,分析了适用于多媒体通信的各种通信网络,最后论述了多媒体通信中的两项关键技术,即多媒体信息压缩技术和同步技术。     

IPTV的关键技术及发展现状

随着互联网宽带业务的不断发展,IPTV这一新的服务模式正在成为现实。本文主要介绍IPTV技术原理和关键技术,并对国内目前IPTV的发展状况进行分析。     

Recent Developments in Fault Detection and Power Loss Estimation of Electrolytic Capacitors

This paper proposes a comparative study of current-controlled hysteresis and pulsewidth modulation (PWM) techniques, and their influence upon power loss dissipation in a power-factor controller (PFC) output filtering capacitors. First, theoretical calculation of low-frequency and high-frequency components of the capacitor current is presented in the two cases, as well as the total harmonic distortion of the source current. Second, we prove that the methods already used to determine the capacitor power losses are not accurate because of the capacitor model chosen. In fact, a new electric equivalent scheme of electrolytic capacitors is determined using genetic algorithms. This model, characterized by frequency-independent parameters, redraws with accuracy the capacitor behavior for large frequency and temperature ranges. Thereby, the new capacitor model is integrated into the converter, and then, software simulation is carried out to determine the power losses for both control techniques. Due to this model, the equivalent series resistance (ESR) increase at high frequencies due to the skin effect is taken into account. Finally, for hysteresis and PWM controls, we suggest a method to determine the value of the series resistance and the remaining time to failure, based on the measurement of the output ripple voltage at steady-state and transient-state converter working.      

Millimeter Wave and Terahertz Communications： Feasibility and Challenges

In this paper, the challenges with and motivations for developing millimeter wave and terahertz communications are described. A high-level candidate architecture is presented, and use cases highlighting the potential applicability of high-frequency links are discussed. Mobility challenges at these higher frequencies are also discussed. Difficulties that arise as a result of high carrier frequencies and higher path loss can be overcome by practical, higher-gain antennas that have the added benefit of reducing intercell interference. Simulation methodology and results are given. The results show that millimeter wave coverage is possible in large, outdoor spaces, and only a reasonable number of base stations are needed. Network throughput can exceed 25 Gbit/s, and cell-edge user throughput can reach approximately 100 Mbit/s.