微波传输系统真空法兰密封结构设计特点

为了提高微波传输系统最大输出功率,将波导管内维持真空状态,真空度达到或优于10-5Pa时,通过功率可提高几个数量级。但真空波导法兰密封结构设计是关键,对应不同的条件有不同的要求。首先,在橡胶密封圈的波导法兰上设计抗流结构,利用“等效电路”、“短路”和高频电流波节等相互关系,使法兰机械设计和制造工艺满足微波功率输出的要求;其次,金属密封垫片法兰根据方波导管高频电流分布的特点,采用法兰方波导宽边良好的电接触与真空密封结构分开设计的方式;再次,另一种在金属密封垫片法兰上加工一个与方波导管内壁一致的方形刀口,在螺栓力作用下刀口与密封圈四周挤压接触,既达到真空密封,又满足良好的电接触,设计、加工、装配简单。这三种法兰都不影响波导管电磁能量的传播,但真空密封性能、机械设计、加工等方面存在差异。

Different Vacuum Sealing and Microwave Transport

The influence of vacuum sealing,with diferent materials and geometries,on microwave transport was tentatively discussed.In the case of viton O-ring,anti-current structure on the flange should be designed,on the basis of the interdependence of the equivalent circuit,short circuit,and high frequency current wave node,to meet the power output requirement.For rectangular-shaped flange with metal gasket sealing,good electric contact and vacuum sealing should be designed separately.In addition,the knife edge with square cross-section on the flange improves the contact and sealing after tightening the bolts.We concluded that the different flange designs discussed above little affect the transport of microwave.