空间大功率微波无源互调的非接触电磁调控抑制方法研究

Passive intermodulation (PIM) is an important bottleneck problem of high power microwave components and systems, which seriously affects the normal operation of satellite communication systems. Metallic contact nonlinearity is the main source of PIM. Currently, the main method of PIM suppression is to improve the contact condition of the connection structure, requiring complicated process of surface treatment and assembly, which is high of cost and could not get a stable PIM performance. The PIM suppression requirement and the advantage of non-physical-contact structure of contactless electromagnetic control technology is combined in this project, and several scientific problems will be explored, to study a novel PIM suppression method based on contactless principle, for high power space applications. First, several novel contactless EBG structure with compact size and high power capacity have to be proposed and studied, which is suitable for the low frequency and high power applications. Then, high power contactless EM transmission channel will be constructed by contactless EBG technology and high power contactless microwave connection can be realized with no metallic contact, by which the low PIM connection can be realized with stable PIM performance. Furthermore, to solve the problem of introducing nonlinearity during the manufacturing, assembly and tuning process of traditional high power microwave components, the contactless assembly and contactless tuning method will be investigated, which is aimed to achieve a total contactless design of the high power microwave components, and the metallic contact nonlinearity of traditional microwave components will be completely eliminated, an efficient and stable PIM suppression method is therefore achieved, which can provide new approaches for low PIM design of high power microwave components and systems for space applications.

无源互调是大功率微波部件及系统中的重要瓶颈问题，严重影响着卫星通信系统的正常工作。金属接触非线性是产生无源互调的主要根源。目前的无源互调抑制技术主要通过改善接触实现，工艺复杂、成本高且性能不稳定。本项目将无源互调抑制需求同非接触电磁调控的非接触结构优势相结合，梳理其中的科学问题，开展基于非接触思想的空间大功率微波无源互调抑制方法研究。研究适用于空间大功率应用的多种新型小型化、高功率容量非接触电磁带隙结构，基于此构建大功率非接触式电磁传输通道，实现高效稳定的大功率低无源互调微波连接。此外，针对传统大功率微波部件在制造、装配及调试过程中引入接触非线性源的问题，研究大功率微波部件的非接触组装及非接触调谐技术，进而实现大功率微波部件的全面非电接触化设计，从根本上彻底消除产生无源互调的金属接触非线性，实现对大功率微波无源互调的高效、稳定抑制，为空间大功率微波部件及系统的低无源互调设计提供技术基础。

无源互调是微波系统中的一种常见干扰，对于航天器通信系统有着致命影响，是制约我国航天装备发展的瓶颈问题，无源互调抑制技术是卫星及地面通信中的核心关键技术。本项目独辟蹊径，开展了新型非接触式人工电磁带隙材料与无源互调干扰抑制的交叉融合创新研究及相关的设计验证，主要研究工作和进展如下：.1. 提出了金属板间周期性单元任意互补加载的新型非接触EBG材料模型，拓展了非接触EBG的广义内涵，降低了高频段下钉床式非接触EBG材料的加工制造难度，大幅提升了钉床式非接触EBG材料的工作频段范围，具有高度的设计及应用灵活度；.2. 提出了新型滑动对称褶皱型双间隙非接触EBG材料，相比传统双间隙EBG结构尺寸缩减近50%，为小型化双间隙非接触式微波毫米波器件电路应用提供了新途径。基于褶皱双间隙非接触EBG材料实现了新型的插入式低PIM适配技术，为实现波导类部件及系统接口间快速稳健的低PIM电连接提供了新途径，实测PIM抑制度＞25dB；.3. 发明了宽带小型化非接触式低PIM波导连接器，实测PIM抑制度＞30dB，获得了与表面状态及连接力矩无关的稳定低PIM性能，解决了低频非接触法兰尺寸过大难以应用的问题。.4. 发明了基片集成式低PIM垫片过渡技术，实现了小型轻量且快速便捷的低PIM电连接应用，完成了Ku频段矩形波导法兰的低PIM电连接技术验证，实测PIM抑制度＞20dB。.5. 针对航天器低PIM微波部件需求，提出了全非电接触式低PIM微波部件技术及多种小型化设计方法，可获得微波部件的近乎“无PIM”性能，有效解决了传统低PIM微波部件制造、装配及检测过程繁琐复杂，PIM性能稳定度不高的问题。.6. 研制了极高灵敏度PIM检测系统，PIM噪声指标较同类系统改善＞10dB，且具有极高的检测稳定度，为高性能、高效率PIM检测提供了新的方法和途径。