Two-Wave Ka-Band Nanosecond Relativistic Cherenkov Oscillator

TLDR

The wavelength λ is a wavelength. The study presents numerical and experimental results of a Ka‑band relativistic Cherenkov oscillator with slow‑wave structure diameter ≈ 2.6 λ. The experiment used combined mode selection with diffraction loss control and a high‑current accelerator SINUS200 to generate a thin‑walled annular electron beam at 350‑420 kV, 2.9‑3.8 kA, and 10‑ns pulses. The oscillator produced 2.5‑3‑ns pulses at 36.4‑36.8 GHz with 400‑600 MW peak power and achieved a 42 % ± 5 % conversion efficiency.

Abstract

This paper presents the results of numerical and experimental study of a Ka-band relativistic Cherenkov oscillator with average diameter of the slow-wave structure D ≈ 2.6λ. (λ is a wavelength). The combined mode selection including the diffraction loss in the electron diode was applied. The high-current accelerator SINUS200 provided the thin-walled annular electron beam in the range of voltages 350-420 kV and currents of 2.9-3.8 kA at pulsewidth of 10 ns. The generation of 2.5-3-ns pulses at the central frequency 36.4-36.8-GHz and 400-600-MW output microwave peak power was realized. The corresponding efficiency of 42% ± 5% in power conversion has been obtained.