Investigation of a cross-band relativistic Cherenkov oscillator based on the cathode adjustment

Peng Zhang,Xingjun Ge,Xinbing Cheng,Chenyu Zhao,Qiang Zhang,Fangchao Dang,Chao Huang,Junpu Ling

doi:10.1063/1.5086190

Abstract

The mechanism and realization of a cross-band relativistic Cherenkov oscillator based on the cathode adjustment are presented. The device adopts coaxial dual-annular cathode to emit the inner and the outer electron beams, independently. When the inner annular cathode is extended and the outer annular cathode is retracted, the electron beams are emitted from the inner cathode and interact with the internal electromagnetic structure to generate Ka-band microwaves. On the contrary, the outer electron beams interact with the external electromagnetic structure to generate X-band microwaves. Thus, the cross-band microwave generation can be achieved only by adjusting the protrusion and retraction of dual-annular cathode. By the particle-in-cell (PIC) method, the physical process of beam-wave interaction in the device is studied, and the high efficiency internal-external double electromagnetic structures are designed. Simulation results show that the X-band microwave with a power of 1.50 GW and a frequency of 8.55 GHz is generated, corresponding to an efficiency of 32%. Meanwhile, the Ka-band microwave with power of 650 MW and frequency of 31.80 GHz is generated, corresponding to efficiency of 28%.

Highlights

There are so many reports on the relativistic Cherenkov oscillators1–5 operating in a single frequency,6–13 but discussions on frequency tuning devices are scanty
Schamiltoglu et al17 reported the X-band mechanical tuning RBWO, which got the frequency tuning bandwidth within 5% by varying the drift length between the SWSs and the reflector and the drift length between the cutoff neck and the SWSs
A cross-band relativistic Cherenkov oscillator based on the cathode adjustment is studied in this paper

Summary

INTRODUCTION

There are so many reports on the relativistic Cherenkov oscillators operating in a single frequency, but discussions on frequency tuning devices are scanty. It should be mentioned that the frequency tuning devices have very important applications in both military and industrial fields.. The investigation on the frequency tuning devices is of great interest to the high power microwave (HPMs) field.. In 2017, Xingjun Ge et al adopts the same technique to realize a relativistic backward-wave oscillator with frequency selectable across X- and Ku-bands. The operation frequency can jump across multi-bands (X- and Ka-bands). The device adopts double electromagnetic structures to make the beam-wave interaction independent.

DEVICE STRUCTURE

PHYSICAL DESIGN

The longitudinal mode selection

The typical simulation results

Guiding magnetic field

CONCLUSIONS