精密机械同轴扫描开关研制

在精密电测领域，鲜有面向交流自动测试系统的专用同轴扫描开关。针对于此，设计了一种4线制 15通道全同轴扫描开关装置。该装置以步进电机精密运动控制为基础，拖动快插式同轴线组件做X-Y双向定位运动，实现同轴测量通道的可靠自动切换。通过自主设计柔性对接机构，消除因运动失准导致的通道对接误差及不可逆物理损伤风险。通过分析通道热电势、泄漏阻抗、寄生电容、感性耦合电势等寄生参数的产生机理，明确了影响扫描开关电气特性的关键设计参数，进而提出针对性优化设计方法。测试结果表明，所研制扫描开关装置的通道热电势小于±50 nV，通道对地泄漏阻抗达到1014 Ω量级，通道间寄生电容小于1×10-5 pF，通道间的感性耦合系数小于1.2×10-10 H。

Development of precise mechanical coaxial scanner

In the field of precision electrical measurement, there are few special coaxial scanner for AC automatic test systems. Aiming at this, a 4-wire-15 channel all-coaxial scanner device is designed. The device is based on the precision motion control of the stepper motor, and drags the fast-plug-in coaxial axis component to do X-Y bidirectional positioning motion, realizing the reliable automatic switching of the coaxial measurement channel. By independently designing the flexible docking mechanism, the risk of channel docking error and irreversible physical damage caused by movement misalignment are eliminated. By analyzing the generation mechanism of parasitic parameters such as channel thermal electromotive force, leakage impedance, parasitic capacitance and inductive coupling potential, the key design parameters affecting the electrical characteristics of scanner are defined, and then the targeted optimization design method is proposed. The test results demonstrate that the thermal electromotive force in the scanner channel is less than ±50 nV, the leakage impedance of the channel to the ground reaches 1014 Ω, and the parasitic capacitance between the channels is less than 1×10-5 pF, additionally, the inductive coupling coefficient between channels is less than 1.2×10-10 H.