基于THz QCL 和THz QWP 的数字通信演示系统

随着无线通信速率需求的增加和材料生长、器件工艺制作水平的提高,太赫兹（THz）通信已成为未来高速无线通信系统发展的一个重要方向。介绍了太赫兹通信的特点以及国际上太赫兹通信系统的发展现状,并报导了一种利用太赫兹量子级联激光器（THz QCL）作为发射源,太赫兹量子阱探测器（THz QWP）作为接收器的太赫兹数字通信演示系统。该系统采用On-Off-Key（OOK）调制和直接强度检测方式,通信频点为3.9 THz,通信距离为2.2 m,传输速率可达1 Mbps 以上。最后探讨了该系统的带宽限制因素及其在通信速率方面的潜力。     

太赫兹量子阱探测器研究进展

太赫兹量子阱探测器具有皮秒级的响应时间和1 GHz以上的高速调制性能,是太赫兹快速成像和高速无线通信应用领域非常有前景的探测器.文章综述了太赫兹量子阱探测器的探测原理和设计方法、器件主要性能指标和基于该探测器的应用技术研究进展.研究表明,基于太赫兹量子阱探测器的快速成像系统可以获得物体的细节信息,有望用于安全检查和无损...     

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。     

用于太赫兹高速直接调制技术研究进展

分析了近年来太赫兹直接调制技术的发展情况,技术特点以及应用前景。随着外调制技术的快速发展,调制速率有大幅度的提高,并且与目前主流的基于肖特基二极管等固态器件太赫兹发射链路易于集成等特点,已被认为是一种在太赫兹高速通信领域中具有应前景的太赫兹调制技术。     

太赫兹通信系统的研究现状与应用展望

随着无线通信技术的发展,对无线通信速率和频率的要求逐年提高。现有无线通信频段已趋于饱和,而太赫兹频段是一个全新的空间。本文按照产生方式分类对近年国内外太赫兹通信研究最新进展进行了综述,并给出未来太赫兹通信系统在光载无线通信、空间领域、军事领域上的可能应用方向。     

太赫兹高速无线通信：体制、技术与验证系统

对太赫兹高速无线通信的国内外现状和发展趋势进行了全面的综述与分析。首先介绍了太赫兹通信的特点、频段和调制体制。在此基础上详细讨论了太赫兹无线通信的关键技术,包括太赫兹产生和功率放大技术、太赫兹接收检测技术、太赫兹调制解调技术、太赫兹传输技术、太赫兹高速通信数据流和网络协议技术、太赫兹集成微系统技术;然后重点介绍了日本、德国、美国和中国的几个典型的太赫兹通信验证系统;最后对太赫兹高速无线通信的应用和发展进行了展望。     

140GHz高速无线通信技术研究

随着经济的发展以及互联网技术的进步,人们对于无线通信的速率要求越来越高。高速无线通信从传统的Mbps转变为Gbps已经成为一个研究热点之一,现阶段已经取得了较大的进步。目前140GHz高速无线通信技术主要存在的弱点是辐射功率不够高、调节调制过程中比较困难以及受到天气的影响较重等,本文将从太赫兹通信验证系统、光通信系统以及微波毫米波通信系统等角度出发,研究显示太赫兹通信验证系统对140GHz无线通信技术的应用前景比较广泛。     

基于硅基石墨烯的全光控太赫兹波强度调制系统研究

在太赫兹通信等系统中需要利用太赫兹波调制器对信号进行调制.基于GaAs 等传统半导体材料设计和制作的调制器在太赫兹波段的响应过低,因而很难应用于太赫兹系统.为了弥补传统调制技术在带宽和调制深度不够的缺点,设计了一种全新的基于硅基石墨烯的全光控太赫兹强度调制系统.该调制系统利用材料中光生载流子对太赫兹波的吸收特性,通过调节照射到材料上的可见光光强来改变光生载流子浓度,从而实现对太赫兹波强度调制.从理论和实验两方面对这种新型太赫兹强度调制系统的调制深度和调制带宽进行了研究.研究结果表明,在泵浦光功率密度为18 mW/mm2时,该调制系统能在实验使用的THz-TDS 测试系统(0.1~2.5 THz)的整个频谱范围内进行有效的调制,调制深度可达到12 %.且随着泵浦光能量的增大,调制深度增大.     

太赫兹探测与通信技术新进展

回顾了太赫兹技术的最新进展,并总结了未来的几个重要方向,重点介绍几种关键的太赫兹技术,包括太赫兹源、太赫兹传输、太赫兹调制和太赫兹检测。简要介绍了当前太赫兹技术的发展现状和应用情况,如射电天文学、物体无损检测、医疗成像、安检等太赫兹探测应用和太赫兹通信概况。对太赫兹探测和通信最新技术进展进行了回顾,给出了该领域的前瞻研究方向。     

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。     

THz wireless communication system based on wavelet transform

With a very wide frequency band not allocated at present, THz waves have many optimal characteristics such as high transmission rate, large capacity, and high security. The research of THz communication technology has become a hotspot in wireless communication. For THz wireless communications, it is crucial to study advanced electrical signal processing techniques. In this paper, in view of the shortcomings of traditional orthogonal frequency division multiplexing (OFDM) technology, we propose wavelet transform orthogonal multicarrier modulation method in THz system. In addition, we study THz channel coding technology to ensure that the THz wireless communication baseband system has better bit error rate (BER) performance and low computational complexity. Based on above, a THz wireless communication baseband system is conceived.     

0.14 THz 10 Gbps无线通信系统

太赫兹通信由于其固有的宽带特性,在Gbps以上的高速无线通信领域受到广泛关注。本文描述了一种工作在0.14 THz频段的无线通信系统,传输速率达10 Gbps。该系统基于超外差结构,中频采用数字信号处理技术进行16QAM高阶数字信号调制解调,依靠肖特基二极管次谐波混频技术实现从中频到太赫兹信号的频谱搬移。目前该系统已经通过了500 m 10 Gbps距离无线传输实验验证,通信频段为133.8 GHz～137.4 GHz,带宽3.6 GHz,发射功率0 dBm,传输误码率低于10-6。     

（英）Orthogonal frequency division multiplexing for improving the performance of terahertz channel

Terahertz (THz) communication is considered to be one of the demanding technology for the upcoming 5G standards. The incredible demand for high rate through wireless channel necessitates the use of THz frequency for communication. The development of communication systems in this frequency band possess technical challenges as the characteristic of THz band is very much different from the present wireless channel. However, the advancements in the development of transceiver and antenna systems are rapidly bringing the THz communication into reality. The high path loss in THz band limits the communication range of this channel. Even, for a distance of few meters (>5m), the absorption coefficient is very high and hence the performance of the system is poor. Performance over this frequency channel can be enhanced by considering transmission windows over this band instead of the entire band. The transmission windows are the frequencies over which the absorption is relatively low. Though there is an improvement in the performance with this adaptive modulation scheme, but not sufficient for longer distance. Apart from path loss, the frequency selective nature of this high bandwidth channel is also a major reason for the poor performance of THz channel. Orthogonal Frequency Division Multiplexing (OFDM) is a promising solution to mitigate the effects of frequency selective nature of the wireless channel. OFDM has been exploited in this paper to improve the performance of terahertz channel. The results show that the Bit Error Rate (BER) of the terahertz channel is considerably improved with OFDM.     

地空路径太赫兹波雨天衰减特性分析

雨滴的散射和吸收作用会严重增加地空链路上太赫兹波的传输损耗,降低无线通信的性能。为实现太赫兹波在地空链路上的传输应用,必须对太赫兹波在降雨环境中的传输特性进行深入研究。本文对原有的雨衰模型进行了修正,基于Mie理论,分析了降雨率的变化对地空链路上太赫兹波传输的影响,并与原有模型的计算结果进行了对比。结果表明：在整个太赫兹频段,雨衰减损耗会随降雨率的增加而增大,随频率的增加先增大后减小,且高频太赫兹波段相对0.1~1 THz频段范围的雨衰损耗更小;同时,当频率超过1 THz时,大气窗口越靠近10 THz,损耗越小,在降雨天气环境进行无线通信传输时将更具有通信优势,且频率越低,天顶角越大,模型修正前后的差异性更加明显。     

Study of atmospheric attenuation characteristics of terahertz wave based on line‐by‐line integration

Terahertz band communication promises new solution for satisfying the increasing demand for ultrahigh‐speed wireless communication. Channel models capturing the unique peculiarities of the terahertz (THz) band are required for communication systems designing. Extreme high molecular absorption is a distinctive phenomenon that has to be involved in terahertz communication models. Research in this field has mainly focused on the characteristics along the horizontal propagation path. In this paper, we developed a unified molecular absorption model along the slant propagation path of the THz wave, based on the line‐by‐line integration method developed by Van‐Vleck and Weisskopf and combining the molecular spectral line in the HITRAN database. Then, an in‐depth analysis on the THz channel characteristics is carried out by the developed propagation models. The attenuation characteristics of terahertz waves with frequencies in the range of 0.1 to 1 THz are analyzed by theoretical and mathematical modeling. The results show that the terahertz communication channel has a strong dependence on both the molecular composition of the medium and the transmission distance. The experimental results also indicate the strong absorption frequency points, weak absorption frequency points, and spectral windows.     

基于Lambertian模型的星间太赫兹通信信道特性分析

随着数据传输速率的不断增长,6G无线通信系统需要采用新的频谱资源.太赫兹频段因其具有高带宽、高速率等特点,在未来的无线通信领域具有极大的优势.另一方面,为了应对未来无线通信网络全球覆盖的要求,6G通信网络需要集成地面通信网络和空间通信网络.本文利用射线追踪理论,对太赫兹频段的星间通信链路的确定性信道模型进行了研究.由于...     

Performance of terahertz channel with multiple input multiple output techniques

Terahertz (THz) communication is being considered as a potential solution to mitigate the demand for high bandwidth. The characteristic of THz band is relatively different from present wireless channel and imposes technical challenges in the design and development of communication systems. Due to the high path loss in THz band, wireless THz communication can be used for relatively short distances. Even, for a distance of few meters (>5m), the absorption coefficient is very high and hence the performance of the system is poor. The use of multiple antennas for wireless communication systems has gained overwhelming interest during the last two decades. Multiple Input Multiple Output (MIMO) Spatial diversity technique has been exploited in this paper to improve the performance in terahertz band. The results show that the Bit Error Rate (BER) is considerably improved for short distance (<5m) with MIMO. However, as the distance increases, the improvement in the error performance is not significant even with increase in the order of diversity. This is because, as distance increases, in some frequency bands the signal gets absorbed by water vapor and results in poor transmission. Adaptive modulation scheme is implemented to avoid these error prone frequencies. Adaptive modulation with receiver diversity is proposed in this work and has improved the BER performance of the channel for distance greater than 5m.