G-S. Park
Seoul National University, -, South Korea
Keywords: Field electron emitter, cathode, HPM, Graphene film, Gigawatt
MILO, the Relativistic Backward Wave Oscillator (RBWO), and the Relativistic Magnetron are key gigawatt-level High-Power Microwaves (HPM) for defense. Their efficiency is largely linked to cathode quality, which generates and emits electrons. Ideal cathodes should have high current density, durability, uniform electron emission, and be compatible with pulse-power systems. Historically, HPMs used thermionic cathodes, but they were power-inefficient. Field emission cathodes introduced later faced tip degradation and gas ionization issues. Although Carbon nanotubes (CNTs) brought advancements, they grappled with fabrication issues and potential degradation. Enter the 2.5D graphene film: with conductivity at 1.95×10^6 S·m^-1, electron mobility of 818 cm^2·V^-1·s^-1, and thermal conductivities nearing 2000 W·m^-1·K^-1. This cathode sustains 50 mA emission at ~10 kV and remains resilient over 25 days. Leveraging our MILO and RBWO experience, we're examining this cathode's performance in HPMs.