全电子太赫兹星地高速通信关键技术

摘要：面向低轨卫星高速数据下传需求，针对太赫兹星地通信中大气衰减显著、星载资源受限及波束跟踪精度要求高等问题，本文结合太赫兹传播特性和现有技术，开展系统级分析。通过比较地面验证系统与空间载荷架构，推荐“星载端简化、地面端增强”的非对称全电子学架构；综合大气吸收、天线口径、传输容量和器件性能，建议采用220 GHz中心频率。结合青海站气象衰减参考值及前瞻性器件参数，以64APSK调制、码率5/6为代表工况，参考DVB-S2X公开性能参数进行链路预算。在40 Gbaud下，理论有效信息速率约197.5 Gbit/s，估算链路余量约为8.7 dB。进一步讨论高功率发射、低温高灵敏度接收、分层波束跟踪及高能效基带处理的实现途径，为系统设计与试验验证提供参考。

关键词：全电子太赫兹；星地通信；高速通信；太赫兹收发机

Abstract: To meet the demand for high-speed data downlink from low Earth orbit (LEO) satellites, this paper presents a system-level analysis of all-electronic terahertz satellite-to-ground communications, addressing challenges such as significant atmospheric attenuation, limited onboard resources, and stringent beam tracking requirements. By comparing terrestrial demonstration systems and spaceborne payload architectures, an asymmetric all-electronic architecture featuring a simplified spaceborne terminal and an enhanced ground terminal is recommended. Considering atmospheric absorption, antenna aperture, transmission capacity, and device performance, 220 GHz is recommended as the operating center frequency. Based on atmospheric attenuation estimates for the Qinghai ground station and prospective device parameters, a link budget analysis is conducted using 64APSK modulation with a coding rate of 5/6 as a representative configuration, with reference to published DVB-S2X performance parameters. At a symbol rate of 40 Gbaud, the theoretical effective information rate is approximately 197.5 Gbit/s, with an estimated link margin of 8.7 dB. Key implementation approaches for high-power transmission, high-sensitivity cryogenic reception, hierarchical beam tracking, and energy-efficient baseband processing are further discussed, providing guidance for system design and experimental validation.

Keywords: all-electronic terahertz; satellite–ground communication; high-speed communication; terahertz transceiver