超导混频接收中全固态本振的若干关键技术研究

With the high resolution and high sensitivity requirements to astronomical observations and atmospheric sounding, the LO's contribution to the low frequency noise performance of the receiving system are the ongoing focus of these areas. We propose two key issues to be carried out about the solid-state local oscillator in superconducting mixer receiver research. They are the low frequency noise analysis of the local oscillator reference & noise-reduction technology, and the thermoelectric model of the high power local oscillator frequency multiplying devices & its low-frequency noise analysis separately. Using the sapphire oscillator as a microwave reference in the THz solid source source, the Output THz signal has a merit of low frequency noise performance. We intends to carry out theoretical model analysis of the noise-reduction & frequency-locking loop design techniques to accomplish a ultra-low phase noise circuit design which can reduce the low frequency noise of the local oscillator reference itself and low frequency noise introduced to the frequency multipliers. To THz multiplier's research, the high power THz multiplier and its low frequency noise characteristics is the new critical facing issue. We intend to carry out the thermoelectric model analysis of the high power THz frequency multiplier and the more detailed re-discussion about the multiplying mechanism. By building the THz multiplier thermoelectric model, improving our self-design THz frequency multiplier design process, we wish to accomplish the optimization of the high power multiplier, low frequency noise characteristics and the impaction to the stability of the system. The research and its conclusions can be used for THz local oscillator design, system measurement and the optimization to the observation strategy.

随着天文观测和大气探测对接收越来越有着高分辨率及高灵敏度的要求，本振对于系统低频噪声的贡献渐渐受到关注。拟开展超导混频接收中全固态本振的关键技术研究，分别是本振基准源低频噪声分析及低频噪声减小技术研究、高功率倍频器件热电模型及倍频器件低频噪声分析等内容。 在太赫兹波波段，若采用蓝宝石振荡器作为THz固态源的微波基准源，所输出THz信号低频噪声性能优异，可降低本振基准源低频噪声，有效减少其对后续本振倍频链路及超导混频电路的低频噪声引入。 高功率THz倍频输出以及THz链路低频噪声的特性分析，是全固态源研究面临的新问题。亟需开展对倍频机理的再讨论，即高功率THz倍频器件热电模型研究，进一步完善THz倍频电路特性分析与电路设计流程，完成高功率倍频电路优化设计以及低频噪声特性分析，有效提高系统稳定性。 本项目研究及其结论可作THz本振设计、系统测试及观测策略优化的参考依据。

建立了本振基准源主振环路及锁频电路相噪模型，完成了振荡电路相噪指标与鉴频灵敏度、谐振器耦合度及分立器件关联性分析和讨论，所得结论对实际振荡电路的研制具有重要的理论指导意义；具有放大、衰减、移相、耦合、环形、隔离等功能的各类有源/无源微波二端口器件是超低相噪基准源的重要组成部分，基于干涉理论，研制出二端口器件1/f噪声干涉测量系统，测试系统底噪为-170dBc/Hz，达到国际同类系统底噪指标，该测试平台非常有助于低1/f噪声器件的选型，并利用该测试系统完成了若干二端口器件的1/f噪声测试；研制出超低相位噪声基准源，根据对关键相噪指标的实测，表明该基准源性能优越，相噪指标在偏离载频1 kHz处相位噪声为-112 dBc/Hz@10GHz，偏离载频10 kHz处相位噪声为-142 dBc/Hz@10GHz。.完成了高功率条件下太赫兹肖特基器件的倍频机理与工作机制的分析研究，设计出新型倍频电路合成结构，该新型倍频电路在高功率推动条件下，不需改变原有肖特基器件功率承载能力，通过增加倍频器件的数量来提高倍频链路的功率承载能力，同时优化后的电路倍频效率并无损失，并得到两倍原先倍频设计的输出功率；开展了太赫兹肖特基器件噪声模型及热电模型分析研究，并完成各自模型的器件级及电路级表征技术的研究 。所开展的器件噪声模型、热电模型、模型电路表征，倍频拓扑、倍频机制、导波模式等方面的基础理论和技术方法研究，对于建立并完善太赫兹倍频电路协同仿真设计平台有重要的意义；研制出可应用于成像的太赫兹肖特基检波电路，检测灵敏度达到3500mV/mW左右，线性度0.998，性能优越；研制出0.2THz、0.3THz、0.6THz高效倍频电路实物，倍频效率和功率指标性能优越，并实际应用与欧盟优先级最高的L-1级空间探测项目- Jupiter Icy Moon Explorer（JUICE）中0.6THz和1.2THz亚毫米波探测器。