冷阴极高阻抗相对论速调管放大器的模拟研究*(高功率微波专题组稿)

采用MAGIC 2.5-D模拟软件,建立了基于冷阴极发射实心束的高阻抗相对论速调管放大器模型。该模型由一个带屏蔽环的二极管,5个简单药盒型谐振腔和1个锥形收集极构成。为了给具有高效率的高阻抗相对论速调管提供实心束,同时实现设备的简单化和紧凑化,采用冷阴极取代传统的热电子枪,不仅易操作而且大大降低能耗和经费。通过在传统二极管阴极侧面引入屏蔽环,利用屏蔽极大地提高电子束阻抗,同时其位置和形状能明显降低非发射区的场强,并且有效改善阴极端面发射的均匀性。在束波互作用区,通过依次调节末前腔和输出腔的位置并结合导引磁场的大小对输出的微波进行优化,结果表明：在二极管发射电压525 kV、电流328 A的实心束及外加磁场0.35 T的条件下, 当注入功率为1 kW时, 在11.424GHz的中心频率处获得了功率81 MW,效率47 %,增益49 dB的微波。

Simulation of a high impedance relativistic klystron amplifier with a cold cathode

A high impedance relativistic klystron amplifier (RKA) with a cold solid cathode is designed and investigated by 2.5-D particle-in-cell simulations. The model is composed of a diode with a shielding ring, five pill-box cavities and a cone collector. In order to simplify and minimize the cathode structure, a cold cathode is designed and adopted in a high-impedance RKA with rather high conversion efficiency. A shielding ring is introduced to achieve the desired high impedance and reduces the surface electric ?eld to avoid unexpected explosive emissions and ensures the emission uniformity. In the beam-wave interaction region, with optimization of the position of the last two cavities and the magnetic field, the performance of the klystron is validated. It reveals that microwaves with a power of 81 MW are generated at a frequency of 11.424 GHz when the beam voltage and current are 525 kV and 328 A respectively, under a guiding magnetic ?eld of 0.35 T. The corresponding power conversion efficiency is as high as 47 %, and the gain reaches 49 dB when the net injection power is 1 kW.