Ka波段冷阴极磁控管启动特性研究

冷阴极磁控管是一种性价比很高的可靠微波源,它具有瞬时启动、寿命长、可靠性高、系统容易实现小型化的优点。选用钯钡合金和难熔金属钽作为冷阴极材料,钽环作为一次发射体,由场致发射提供一次电子,钯钡合金为二次发射体,钯钡合金在一次电子的轰击下产生二次电子,两者提供磁控管阴阳极电流,实现磁控管正常振荡。从理论上详细分析了钽环厚度和钯钡合金温度对冷阴极启动特性的影响,基于理论分析结果,开展不同钽环厚度和阴极温度条件下磁控管工作性能研究,最终选用厚度为0.05 mm 的钽环作为冷阴极一次发射体,阴极工作温度在315~836 益之间,成功研制输出功率20 kW的Ka 波段冷阴极磁控管,冷启动稳定时间小于5 s,工作寿命超过500 h

Research on Starting Characteristics of a Ka-Band Magnetron with Cold Secondary Emission Cathode

Cold cathode magnetron is one of the cost-effective and reliable microwave sources. It has many advantages of instantaneous start-up, long lifetime, high reliability, and being easy to realize miniaturization of the system. A cold secondary emission cathode with Tantalum (Ta) and Palladium-barium (PdBa) alloy is proposed in this paper. The Ta disk is selected as the primary emitter and could provide primary electrons by field emission. The PdBa alloy is selected as the secondary emitter and produces the secondary electrons under the back bombardment of the primary electrons. Both of them provide the current of oscillation magnetron together. The influences of Ta-disk thickness and PdBa alloy temperature on starting characteristics of cold cathode are theoretically analyzed in detail. After that, the experimental researches on magnetron with different Ta-disks and cathode temperatures are built. Based on the experimental results, with 0.05 mm Ta-ring as the primary emitter, a 20 kW Ka-band cold secondary emission cathode magnetron is produced successfully and the starting time is less than 5 seconds. The lifetime of this magnetron is more than 500 hours.