Haotian Zhu

太赫兹空间探测系统正向多通道、多谱段和超宽带方向快速发展. 提出基于波导混合网络型的WR-4频段全频带双工器, 用于双频段固态系统中本振信号的合路泵浦. 该双工器基于混合网络的防反射、高隔离耦合等特性, 结合高阶数低通滤波器级联实现, 整体结构鲁棒, 且易于计算机数控(CNC)制备并系统集成. 研究内容主要包括WR-4全频带覆盖混合网络型双工器的原理设计, 分立单元器件混合器、滤波器的电路设计, 混合网络型双工器的电路综合、优化及其E面分裂式CNC铣削加工. 实测结果表明, 该WR-4频段双工器能够实现全频带划分, 含170～210 GHz和210～260 GHz两个通道, 通道内插损低至–1.5 dB和–1 dB, 其中一个通道的隔离高达50 dB, 所有测试结果与仿真数据高度一致. 此外, 该固态双工器电路具有易结构加工、易系统集成、易通道扩展和易频率拓展等特点.

空间被动探测的目标信号通常非常微弱, 并且探测系统需要实现高灵敏度和低噪声的要求. 此时, 冷光学的引入成为必然——通过将光学器件(例如透镜和反射镜)集成到低温环境中, 并结合低温探测器, 实现探测需求. 但由于星载设备的冷量有限, 对传统的光学设计提出了约束与实现难度. 基于冷光学理论, 提出了一种基于多重反射的冷光学模型, 并依据该模型对窗口尺寸进行了优化. 完成了10 THz焦平面阵列成像系统方案设计与漏热计算, 系统采用脉冲管耦合节流制冷的空间制冷技术. 完成了冷光学实验, 理论模型与实验结果相互印证.

太赫兹固态肖特基谐波混频技术是空间天文、行星、大气探测的重要手段, 显然研究太赫兹单片集成谐波混频器具有重要意义. 本文克服了传统混合集成方法(即将分立的肖特基二极管与石英匹配电路胶接而成)存在的装配难、热效应不平衡、可靠性差等系列问题, 基于全自主国产砷化镓流片工艺线, 完成了550 GHz频段单片集成谐波混频器的研制与验证. 二极管设计方面, 建立精确的肖特基变阻管非线性和3D模型; 匹配电路方面, 采用典型的减高波导、高低阻抗悬置微带线(实现RF与LO信号的隔离)、矩形探针等结构, 结合场路分析方法, 实现最简化匹配电路设计; 整体电路含二极管对集成在3 μm厚的GaAs (Gallium Arsenide)薄膜上, 并通过两侧的梁氏引线实现与腔体的固定安装. 测试结果表明: 混频器模块在548～572 GHz单边带变频损耗优于13.4 dB, 并基于此结果实现了设计的反馈仿真研究.

This paper presents the transmission characteristics of flexible solid circular dielectric waveguides in the terahertz frequency band. In this paper, we measured the electrical properties of certain polymers within 325–500 GHz. Through simulation and measurement, the transmission loss, bending loss, and electric field distribution of solid-core polymer dielectric waveguides were analyzed and discussed. Additionally, we considered the surrounding cladding of the dielectric waveguide, the signal-feeding mode transmitter, and the interconnection of the dielectric waveguide. Ultimately, in the operating frequency range of 325–500 GHz, we selected PTFE rods with diameters of 0.5 mm and 1 mm as the dielectric waveguides, with measured transmission loss of less than 30 dB/m and 33 dB/m, respectively, and bending loss of less than 1 dB/m. The described dielectric waveguide has engineering significance for short-distance connections in complex geometric environments and provides a reference for subsequent research.

In this paper, a high-power 170 GHz frequency doubler based on a Schottky diode is proposed using an in-phase power-combining structure. Unlike a conventional power-combining frequency doubler, the proposed frequency doubler utilizes the combination of a T-junction power divider and two bend waveguides to eliminate the phase difference between the two output ports of the T-junction power divider, so as to achieve in-phase power combining with a concise structure. The frequency doubler was fabricated on a 50 μm thick AlN high-thermal-conductivity substrate to reduce the impact of the thermal effect on the performance. The measured results show that the doubler exhibits a conversion efficiency of 11–31.3% in the 165–180 GHz band under 350–400 mW of input power, and a 118 mW peak output power with a 31.3% efficiency was measured at 174 GHz `when the input power was 376 mW. A good agreement was achieved between the simulation results and the measured performance of the doubler, which proves the effectiveness of the proposed in-phase power-combining structure.