A Novel 2-D Slotted Structure Extended Interaction Oscillator

Numerous vacuum electronic devices (VEDs) have been widely studied, among which extended interaction oscillators (EIO) exhibit appealing characteristics, such as high frequency, high efficiency, lightweight, low working voltage, and stable working frequency. The slow wave structure typically adopts the coupled-cavity, folded-waveguide, ladder line, and other structures. The ladder line has a simple structure and is easy to process, with desirable heat dissipation and large power capacity. In this study, a novel slow wave structure being longitudinally slotted in the transverse grating of the original ladder line is proposed, and the 2-D slotted structure can be obtained. Encouragingly, the structure not only increases the cross-sectional area of the electron beam but also, more importantly, increases the effective interaction area to considerably improve the output power. The dispersion characteristics and field distribution are first studied through numerical and simulation calculations, and the optimal slotted structure parameters and working parameters are analyzed using PIC software. Next, a 94-GHz 2-D slotted structure EIO is designed. Finally, compared with the ladder line, the cavity characteristic impedance $\textit{R}$ / $\textit{Q}$ is increased by 52.5%, and the output power is increased by 21.1%. This novel structure is expected to provide a new idea for the power enhancement of millimeter-wave and terahertz EIOs.