A Carbon Nanotube Cold Cathode Microwave Electron Gun

Microwave cold cathode electron gun is an advanced gun type for achieving high current and current density which is very helpful for high frequency microwave vacuum electron devices. To improve the efficiency of microwave generated field emission, a novel cylindrical reentrant resonant cavity with a tapered gradient circular truncated cone and an input coaxial line was designed to minimize the area of the coupling ring and increase the electromagnetic energy transferred to the cavity. Simulation results showed that when applying an input microwave power of 200 W, the cathode surface electric field was up to 3.65 × 10
⁶
V/m, with a maximum field emission current of 1.14 A and a corresponding current density of 9.07 A/cm
²
.