双冗余机制下的传输线特征阻抗分析

航天系统中双点双线等冗余机制, 可能造成传输线并联阻抗变化及信号恶化。针对该问题, 基于多导体传输线理论, 建立了冗余机制下的并联阻抗计算模型, 并对3种常用的共屏蔽结构下5种冗余连接方式的阻抗进行了理论分析和仿真分析。理论分析表明, 冗余电缆组件的阻抗受电缆参数分布矩阵和冗余特征矩阵共同影响。仿真结果表明，四扭结构具有较好的阻抗连续性。与独立的屏蔽结构相比，电缆的四扭结构可以在保持阻抗连续性的同时减轻电缆组件的重量，为运载火箭冗余电缆网的设计提供经验和参考。

Analysis of the characteristic impedance of the transmission line under dual redundancy mechanism

In aerospace system, the redundancy mechanism like dual-line back-up method may change the parallel impedance of the transmission line, which may lead to signal deterioration. In this paper, on the multiconductor transmission line theory, an impedance model in redundant condition is proposed. Theoretical and simulation analysis are performed to evaluate the impedance of five redundant connection styles under three commonly used structures with one shared shielding. Theoretical analysis indacates that the impedance of the redundant cable assemblies is determined by both the parameter matrix and the redundancy feature matrix of the cable. Simulation result indicates that the quad-twisted structure has better impedance continuity than the others. Compared with independent shielding structure, the quad-twisted structure of the cable could reduce the weight of cable assemblies meanwhile maintaining the impedance continuity, which shows an experience and a reference for the design redundancy cable network of launch vehicle.