A novel L-band metamaterial relativistic Cherenkov oscillator with high conversion efficiency

Abstract

A novel all-metal metamaterial slow wave structure (MSWS) which suits high-power microwave sources was proposed in our previous work. Recently, an experiment on the transmission characteristics of the MSWS was carried out. The experiment results show that the MSWS can transmit electromagnetic waves in the 1.40–1.60 GHz frequency band, while the same size circular waveguide TM01 mode has a cutoff frequency of 2.4 GHz. The experiment proved that the MSWS has the advantage of miniaturization. Then, based on the transmission characteristic experiment, a novel L-band relativistic Cherenkov oscillator with miniaturization and high conversion efficiency is proposed. By introducing a new coupled output structure and adjusting the MSWS period at both ends of the output structure, the electromagnetic field is better matched between the MSWS and the output coupler, and the conversion efficiency is increased from the previous 29.2% to 55.8%, with an average output power of 460 MW. Through the analysis of the electric field distribution at the main frequency of the generated microwave, it is determined that the working mechanism of the device is the Cherenkov mechanism.