A high-order mode extended interaction klystron at 0.34 THz

TLDR

High‑order mode extended interaction klystrons operate at the TM31‑2π mode, offering a larger structure and improved performance compared to conventional fundamental‑mode designs. The authors propose a high‑order mode extended interaction klystron for terahertz operation. The EIK comprises five identical cavities each with five gaps, and the design includes techniques to suppress mode competition and self‑oscillation in the high‑order mode cavity. Particle‑in‑cell simulations show the device operates at 342.4 GHz without self‑oscillation, achieving a 43 dB saturation gain and 60 W output power, indicating a promising high‑power terahertz source.

Abstract

We propose the concept of high-order mode extended interaction klystron (EIK) at the terahertz band. Compared to the conventional fundamental mode EIK, it operates at the TM31-2π mode, and its remarkable advantage is to obtain a large structure and good performance. The proposed EIK consists of five identical cavities with five gaps in each cavity. The method is discussed to suppress the mode competition and self-oscillation in the high-order mode cavity. Particle-in-cell simulation demonstrates that the EIK indeed operates at TM31-2π mode without self-oscillation while other modes are well suppressed. Driven by the electron beam with a voltage of 15 kV and a current of 0.3 A, the saturation gain of 43 dB and the output power of 60 W are achieved at the center frequency of 342.4 GHz. The EIK operating at high-order mode seems a promising approach to generate high power terahertz waves.