A Flake Graphite/Titanium Dioxide Composite Cathode for <i>S</i>-Band Relativistic Magnetron

As a source of intense current electron beams, the explosive electron emission cathode has long been the key component of relativistic magnetrons (RMs). However, its application has been hampered by significant limitations: pulse shortening due to plasma expansion and microwave power degradation stemming from emission defects. To mitigate these issues, in this article, a flake graphite/titanium dioxide composite cathode (FTC) with a simple preparation process is proposed. To validate the performance of this cathode, experiments were conducted using a ten-cavity rising-sun relativistic magnetron. The results show that, in comparison to graphite cathodes, the FTC exhibits a remarkable 90% increase in microwave output peak power and a 2-ns extension in pulsewidth. The work in this article aims to provide new ideas for relativistic magnetron cathode design.