面向LCT望远镜的345GHz亚毫米波边带分离接收机研制及其关键技术研究

亚毫米波涵盖了超过一半的宇宙空间光子、星际分子及冷暗天体的辐射特征，因此在射电天文领域具有独特的研究价值。再加上天文探测所具有的高噪声、弱信号、被动探测等特点，亚毫米波天文探测技术已成为现代物理学最前沿和最具有挑战性的研究领域之一。本项目基于我们主导LCT亚毫米波望远镜运行、维护和升级的机会，就降低亚毫米波望远镜系统噪声温度，进一步提升望远镜探测灵敏度的目标进行研究。和双边带SIS接收机相比，边带分离型SIS接收机将上下边带分离，能减小一半的大气噪声温度，从而大大降低望远镜的系统噪声温度。项目中，我们将重点进行345GHz亚毫米波边带分离接收机的设计，研究噪声温度、镜像抑制比和稳定性等核心指标和关键技术问题，分析接收机各子系统噪声来源、确定边带分离技术的制约因素，解决开发高性能亚毫米波边带分离接收机中的关键技术问题。研究为未来LCT望远镜双边带接收机的全面升级提供技术支撑与可行性验证。

Sub-millimeter (Sub-mm) EM radiation has quite unique research values in radio astronomical observation in that more than one half space radiation from cosmos, interstellar molecules, and cold dark celestial bodies has such ‘fingerprint’characteristics. The technologies of sub-mm detection in astrophysics have been one of the most exciting cutting edge fields in modern physics nowadays thanks to high noisy, faint and passive signal features. Based on the opportunities of dominating the LCT operation, maintenance and technology upgrade, the project aims on how to decrease the system noise temperature and further to improve the detection capabilities of LCT telescope. Compared to the dual side-band (DSB) SIS receivers, the atmosphere noise temperature of side-band separation (2SB) receivers is only a half, resulting in a drastic decrease in the system noise temperature. The study focuses on the crucial indices and key technologies including the noise temperature, the image rejection ratio and the stability of 2SB receivers. This helps the physical understanding on the noise origin of the sub-systems and the exploration of the bottle-neck factor of 2SB technologies, enabling the development of high-performance 345 GHz sub-mm 2SB receivers instead of the old DSB receivers. We believe the project provides vital technological references and supports on the exploration of the overall upgrade on 230, 460, and 650 GHz DSB receivers in LCT in the near future.