Dual-parameter mechanically tunable coaxial Cherenkov oscillator

Abstract This paper presents a novel dual-parameter mechanically tunable coaxial Cherenkov oscillator that achieves wide-band frequency tunability while maintaining high conversion efficiency. The proposed device incorporates two independently adjustable mechanical parameters: the inner slow-wave structure position and the tuning ring position. Through precise manipulation of these dual parameters, we demonstrate a continuous frequency tuning range of approximately 700 MHz with power conversion efficiency consistently maintained above 30% throughout the operational bandwidth, reaching peak values of 42% at 9.65 GHz. Particle-in-Cell simulations confirm stable output power levels ranging from 3-4 GW with excellent spectral purity across various tuning configurations. The comprehensive parameter mapping reveals clear interdependence between the tuning mechanisms, providing crucial insights for practical implementation. This approach offers significant advantages over conventional tuning methods, including simplified mechanical design, compact form factor, and enhanced operational flexibility, making it particularly suitable for high-power microwave applications requiring frequency agility in complex electromagnetic environments.