A Novel Cold Cathode Design for S-Band Continuous-Wave Magnetron

An effective design for cold cathode named as the interdigitated field electron emission driving-secondary electron emission (FEE-SEE) cathode is proposed in this article. The cathode consists of an FEE region and an SEE region, which integrates the advantages of the field emission and secondary emission on the M-type device. The excellent FEE performance of the directional single-wall carbon nanotubes (SWCNTs) with an effective method of directly imprinting the SWCNTs sludge on a substrate is studied for obtaining higher primary excitation current. Meanwhile, the cathode prebunch technique is implemented by imposing a fivefold azimuthal variation on the SEE cathode of a ten-cavity magnetron, which could prebunch the electrons into the desired mode at birth to enhance stability and speed startup time. A 3-D particle-in-cell simulation analysis is used to predict a novel cold cathode magnetron with high output power of 3144 W with 6.2% efficiency enhancement with reference to the conventional thermionic cathode applied to the 2450-MHz magnetron. Its startup time is about 100 ns with excellent stability and pure output spectrum.