Abstract
In this paper, we use the method of high order TMn1 mode selection from the concept of narrow-band Smith-Purcell radiation (SPR) for powerful, over-mode, multi-gap extended interaction circuit designs toward millimeter wave and Terahertz (THz) region. As a core part, the multiple gaps interaction structure, equivalent to a subwavelength hole array (SHA), excites the narrow band SPR when an electron beam is injected. The SPR energy is collected by a pair of closed cavities, which satisfies (n-1) standing wave units. The SPR energy in the optimized cavity allows a high index n TMn1 mode operation to achieve the strongest Ez field and high characteristic impedance in a closed multi-gap resonant circuit. This provides an effective design to establish a stable high-order TMn1 mode that supports extended interaction circuits with large cross sections. A 0.46 THz extended interaction circuit, employing the novel high order TM51-2π mode operation output structure, has been designed to demonstrate the efficient beam-wave interaction in the proposed system. The method of TMn1 mode selection provides new insight into the understanding of the high-frequency extended interaction circuits by introducing the SPR concept, benefiting the development of millimeter wave and THz vacuum electron devices (VEDs).
Funder
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Natural Science Foundation of Sichuan Province
Subject
Atomic and Molecular Physics, and Optics