基于外部调制的太赫兹空间高速通信关键技术研究

Terahertz communication is especially suitable for the application of space-based information network for its advantages such as high speed, good beam width and so on. The project will be committed to developing the key technology of terahertz space communication system based on the external modulation. Applying the combination of artificial microstructure (metamaterial) and high electron mobility transistor array structure, a new composite structure terahertz modulator will be constructed. The characteristics of the resonance mode, the internal electric field and the surface current distribution, and the influence on the transmission characteristics of the incident terahertz wave in cell structure under applied voltage will be deeply researched, and the modulation mechanism will be achieved. The design method and machining techniques of the terahertz electronic-control modulator will be grasped. On the basis of the sufficient researches above, the modulation device with switching frequency greater than 10GHz and the modulation depth more than 50% will be developed. An efficient, low power consumption, and reliable new scheme for high-speed signal processing based on one bit quantization will be developed to solve the bottleneck problem in Nyquist sampling of ultra wideband signals. The research on terahertz high-speed space communications scheme will be conducted, and the super-resolution tracking and alignment algorithm based on compressed sensing theories will be studied. The terahertz wireless communication theory verification system will be constructed and the principle of verification experiment will be implemented to obtain the 10Gbps communication rate. The project will provide new avenues for development of space-based information network technology, and it has great significance in enhancing the ability to transmit massive real-time data for space-based information network.

太赫兹通信具有高速率和良好的波束宽度等优点，特别适合空间信息网络应用。本项目将研究基于外调制方式的太赫兹空间通信系统关键技术。采用人工微结构与高电子迁移率晶体管阵列结构相结合构建一种新型复合结构的太赫兹调制器，通过深化研究在外加电压下单元结构中谐振模式、内部电场分布以及表面电流分布变化特性以及对入射太赫兹波传输特性的影响规律，掌握电控调制器的调控机制、设计方法与制备技术，研制出开关频率大于10GHz、调制深度大于50%的调制器件；掌握一比特量化高速信号处理新方法，为超宽带信号的耐奎斯特采样瓶颈问题提供低功耗的解决方案；开展太赫兹空间高速通信方案研究，掌握基于压缩感知的超分辨率跟踪对准算法。在0.2~1THz频段构建通信原理验证系统，开展原理验证实验，实现通信速率10Gbps。该项目的实施将为空间信息网络技术的发展提供新途径，对提升空间信息网络实时海量数据的传递能力具有重要的意义。

本课题针对太赫兹空间高速无线通信的发展需求，开展了太赫兹高速调制器、跟瞄对准算法和高速基带等关键技术研究，构建了10Gbps的太赫兹无线通信系统的原理验证装置，完成了实验室高速通信实验。探索新型相变材料的太赫兹波段电磁特性，结合人工电磁阵列结构，通过外加光信号控制实现太赫兹波的高速调制，研制出光控太赫兹波调制器；探索新型电磁阵列结构与AlGaN/GaN半导体调制掺杂异质结结合形成髙电子迁移率晶体管（HEMT）阵列，通过电压信号控制实现对自由空间传播太赫兹波的快速调制，研制出电控调制器芯片，在0.34THz频段调制速率实现了1Gbps；探索波导结合微带线加载调制器单元结构实现高速太赫兹调制的机理，初步研制出原理器件，在0.22THz频段实现了大于35dB的调制深度，调制速率具备10Gbps能力。针对太赫兹直接调制技术信号采样速率高、基带电路功耗大的难题，提出了太赫兹宽带信道估计和补偿技术、基于低量化比特的采样和接收方法、基于概率计算的电路设计方法，研制出低复杂度、低功耗和小型化的直接调制高速基带,基带速率达到10Gbps；开展了空间通信的超分辨率跟踪对准算法研究，利用张量并行分解的唯一性，以及接收端天线阵的瞄准向量的特殊结构，设计无需格点的超分辨率跟踪对准方法。在上述关键技术研究的基础，构建了0.34THz和0.22THz的太赫兹无线通信原理验证系统，单路传输分别达到了1Gbps和10Gbps传送速率。本课题共培养硕士研究生6名，博士研究生2名；发表SCI论文10篇，申请国内发明专利15项，授权1项，获得美国授权发明专利2项。