Fin-Line Characteristics and Circuits

Bhartia, P.

doi:10.1016/b978-0-12-147699-1.50004-x

Cited by 1 publication

(1 citation statement)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Microwave radiation sources are one of the crucial technologies for modern society. High power sub-millimetre wave sources have attracted significant interest recently due to their potential applications in electron cyclotron resonance heating [1], plasma diagnostics [2], space radar systems [3], communication systems [4], materials science and medical imaging and spectroscopy [5,6].…”

Section: Introductionmentioning

confidence: 99%

Design and simulation of a ∼390 GHz seventh harmonic gyrotron using a large orbit electron beam

Li¹,

He²,

Cross³

et al. 2010

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Abstract. A~390 GHz harmonic gyrotron based on a cusp electron gun has been designed and numerically modelled. The gyrotron operates at the 7 th harmonic of the electron cyclotron frequency with the beam interacting with a TE 71 waveguide mode. Theoretical as well as numerical simulation results using the 3D Particle-In-Cell (PIC) code MAGIC are presented. The cusp gun generated an axis-encircling, annular shaped electron beam of energy 40 keV, current 1.5 A with a velocity ratio of 3. Smooth cylindrical waveguides have been studied as the interaction cavities and their cavity Q optimized for 390 GHz operation. In the simulations 600 W of output power at the design frequency has been demonstrated. [5,6]. The gyrotron is well known as a coherent millimeter wave source capable of high power and high frequency output which is extendable to the Terahertz (THz) frequency region. Recently a gyrotron achieved kilowatts of output power operated at the fundamental electron cyclotron frequency of 1 THz [7] by using a pulsed solenoid. However, continuous wave (CW) operation at such a frequency is a formidable task because of the large magnetic field (~40 T) that is required. As the output frequency increases, both larger magnetic fields and reduced interaction region size are needed when operating at the fundamental cyclotron frequency. An alternative approach to generate CW high frequency radiation is to work at higher cyclotron harmonics [8,9,10,11] which allow the use of larger cavity sizes and smaller magnetic fields by a factor of s, where s is the harmonic number. A CW high harmonic gyrotron operating at a frequency of~390 GHz at relatively lower B-field was designed and is presented in this paper. In this gyrotron cyclotron resonance takes place between the seventh harmonic of the electron cyclotron frequency (s = 7) and the TE 71 waveguide mode. A large orbit electron beam from a cusp gun is used to reduce the possibility of parasitic interactions. The small-signal theory of the beam-wave interaction was used to calculate the growth rate and the starting current. A smooth-bore cavity was designed with a suitable Q value by optimizing the angle of the output taper and the length of the cavity so that the starting current requirement is met. Finally, the beam-wave interaction of the gyrotron was simulated using the 3D Particle-In-Cell (PIC) code MAGIC and the results are presented. Keywords: Harmonic gyrotron, terahertz, large orbit electron beam

show abstract