Demonstration of a Low-Voltage High-Efficiency Continuous-Wave Millimeter-Wave Gyrotron

This brief presents a millimeter-wave gyrotron that operates at a low voltage (below 5 kV) and achieves medium-power, high-efficiency, continuous-wave output. The gyrotron reaches a peak output power of 140 W at a frequency of 30.192 GHz, with an operating voltage and beam current of 4.2 kV and 280 mA, respectively, resulting in an impressive interaction efficiency of 11.9%. Remarkably, even at a reduced voltage of 1.9 kV, the gyrotron can still produce an output power of 5.0 W. The numerical calculation and particle-in-cell (PIC) simulation are conducted to verify the experiment. These results indicate that the gyrotron has the potential to generate medium power with high efficiency at low voltages. The size and cost of the power supply unit for gyrotrons can be significantly reduced. This investigation could advance the development of compact gyrotrons for various applications.