Xiaolin Jin

Recent Developments to the Microwave Tube Simulator Suite

Recent developments to microwave tube simulator suite (MTSS) are reported in this paper. The MTSS is a full-featured tightly integrated software package for microwave tube analysis and design. It includes a commercial grade user interface and three physics simulators. The electron optics simulator is a finite-element (FE) 2-D and 3-D electrostatic steady-state beam trajectory code that has been used to design beam optics, including electron gun and collector. High-frequency circuit simulator is a full 3-D FE computational electromagnetic code that aims to get the accurate electromagnetic wave character spreading in high-frequency structures, such as dispersion, coupling impedance, and attenuation. Beam wave interaction simulator is a large-signal simulation code for helix traveling wave tubes (TWTs), coupled-cavity TWTs, and klystrons. The first version of MTSS was released in 2007, and all of these three physics simulators and user interface are improved and updated over the past six years. This paper reports on some significant advances to MTSS; new Ribbon style user interface, a lot of component modeling templates, more abundant postprocessing features, parallel version, full 64-bit version, more physics, and computation methods improvement.

Recent advances of MICROWAVE TUBE SIMULATOR SUITE

Microwave tube simulator suite (MTSS) is a fully featured software package for microwave tube analysis and design. it consists of four modules now, microwave tube design environment (MTDE), electron optics simulator (EOS), high frequency circuit simulator (HFCS), and beam-wave interaction simulator (BWIS).

Application and validation of Microwave Tube Simulator Suite

Microwave Tube Simulator Suite (MTSS) is a full-featured software package for microwave tube analysis and design. It has been developed by University of Electronic Science and Technology of China (UESTC) and validated against some helix traveling wave tubes.

BWIS_KLY: A 1D large-signal beam wave interaction simulator for klystron

One dimensional beam wave interaction simulator for klystron (BWIS_KLY) which is one module of the microwave-tube simulator (MTSS) was developed. The main features of BWIS_KLY are described.

Design of circular waveguide tapers for a ka-band two-cavity gyroklystron amplifier

Three different kinds of circular waveguide taper are designed for a Ka-band two-cavity gyroklystron amplifier, which are radially shaped to follow a Dolph-Chebyshev profile, a Modified Dolph-Chebyshev Profile and a linear profile respectively. With almost the same taper length, the amplifier using the taper following the Modified Dolph-Chebyshev profile has the appropriate mode conversion and meets the desired performance.

Hybrid genetic algorithm for optimization design of traveling wave tubes

In this paper, an optimization algorithm has been developed to provide robust designs for nonlinear beam-wave interaction of high-frequency traveling-wave tubes (TWTs). The algorithm utilizes the optimization method of hybrid genetic algorithm (Goldberg, 1990) in the TWT simulation code which is much like CHRISTINE-1D (Antonsen, 1998). By considering the effects of dimensional helix pitch variations during the optimization, the desired performance characteristics has been achieved.

Study on the attenuation characteristic of terahertz wave through a non-uniform magnetized plasma

Abstract In this paper, the interaction between terahertz wave and a non-uniform magnetized plasma slab is investigated. The electric field distribution in non-uniform plasma is presented and used to calculate the attenuation of the electromagnetic wave through plasma. Several types of electron density profiles are proposed and discussed. Effects of different plasma parameters (electron density, collision frequency, plasma thickness) and magnetic field amplitudes on THz wave attenuation characteristic are investigated. The transmission ratios at several typical THz signal frequencies in both unmagnetized and magnetized plasma are presented as well. These simulation results are meaningful for the flight communication.

Effects of magnetized plasma on the propagation properties of obliquely incident THz waves

In this paper, the propagation of obliquely incident terahertz (THz) wave in a non-uniform magnetized plasma slab is investigated. The electron density and the collision frequency across the plasma are assumed to have a Gaussian profile. To deal with the non-uniform profile, the plasma slab is divided into a series of subslabs. For more accuracy, twice reflection between the interfaces of each subslab is considered, and the corresponding transmitted and reflected power are derived. Effects of collision frequency, magnetic field amplitude and incident angle on THz wave propagation characteristics are investigated. Specifically, the refraction angles in each subslab are presented. These simulation results are meaningful for the hypersonic flight communication.

The FDTD simulation for scattering characteristics in vacuum tubes

A FDTD code has been developed to calculate the scattering parameter of input and output windows in vacuum tubes. In the code, the FDTD plus CPML1 methods were used with stair mesh approximation. The advantage of FDTD method is that the simulation results of wide frequency can be obtained with single calculation. The CPML absorbing boundary technique was applied to get a reflection below about -95dB with 10 layers. The input and output windows were designed to make sure that the microwave can go in or out of the vacuum tube with reflection as small as possible.

The study of PML in rectangular waveguide for sheet-beam vacuum devices

In this paper, the absorbing boundary condition of Perfectly Matched Layers (PML) is studied for sheet-beam vacuum devices. As a simplified model, the standard rectangular waveguide of the R100 type is simulated with the Finite Differential in Time Domain (FDTD) method and PML. The reflection errors of different absorbing boundary conditions and different microwave modes are given and compared with theoretical numerical error.