VSim for Microwave Devices

VSim for Microwave Devices LogoThe perfect tool for RF and Microwave Engineers, increasing productivity and reducing time to design.



VSim for Microwave Devices Includes the Full Suite of Electromagnetic and Particle Modeling Features for Accurately Simulating RF and Microwave Devices

VSim for Microwave Devices (VSimMD) is a flexible, multiplatform, high-performance, parallel software tool for computationally intensive simulations of microwave devices with accurate simulation of dielectric and metallic shapes using a conformal mesh. Shapes can be easily imported from CAD files or constructed in the user-friendly front end, VSimComposer, and are rapidly meshed with the proprietary VMesh algorithm. The advanced graphics capability of VSim for Microwave Devices displays detailed profile and particle distribution data.

Simulate electron beams with primary and secondary electron emission. Primary emission mechanisms include Child-Langmuir space-charged limited emission, Fowler-Nordheim tunnelling emission, Richardson-Dushman, and user specified. For secondary electron emission, use the pre-installed SEY models, Furman-Pivi, or implement your own. Simulate multipacting at multiple power levels in just one run with field-scaled electrons.VSimMD can be used in the design cycle of specific components such as electron guns, collectors, and couplers. Perform microwave simulation and model high power microwave devices, including kinetic electromagnetic simulation of magnetrons, TWTs, and klystrons. VSimMD enables you to optimize your simulation for multipacting, shunt impedance, and S-Matrix coefficients. Use VSimMD to determine multipacting and perform electromagnetic simulation software with kinetic beams. Multipacting at multiple power levels can be computed in one simulation with the variable coupling electrons.

Examples of simulations of devices and components are included with the product, giving you a jump start for creating your own simulations.

Powerful Technology

VSimMD is a powerful and fast finite-difference code that uses advanced algorithms for handling conformal (non-grid aligned) boundaries. VSimMD implements distributed-memory (MPI) parallelism to enable you to solve any size problem, including the most electromagnetically large device setup. Whether you run VSim on a laptop, a computing cluster, or a supercomputer, your models will run rapidly  using algorithms designed for the exacting demands of high performance computing systems.The full suite of electromagnetic and particle modeling features is available at an affordable price. 


VSim is a flexible, multiplatform, software tool for running computationally intensive electromagnetic, electrostatic, and plasma simulations. VSim easily installs and runs on a variety of systems, including Windows, MacOS, and Linux platforms. Switching between 1, 2, and 3 dimensions is simple with VSim. Work easily in the required dimensionality, whether 1D for the basics, 2D to capture transverse effects, or fully 3D to ensure all geometric effects are included. Design your simulation using a laptop and run it there, or run the simulation on a cluster.

Examples Make VSim Easy to Learn and Reduce Time to Product

Reduce your time from simulation to manufacture of microwave devices with VSimMD.  With its Visual Setup capabilities, the VSimComposer interface enables the user to set up RF device simulations quickly and easily. Through a point and click interface, the user can select solvers and set boundary conditions. The user can also specify absorbing boundaries, controlled voltages, surface emissions, current densities, ports, and waveguides. As with all other VSim simulation packages, both data analysis and visualization functionality are integrated into VSimMD. VSimMD provides 19 ready-made simulation examples for problems such as radiation from an airplane mounted antenna, propagation in a dielectric waveguide, and radar scattering from a metallic object.

Easy to Upgrade

Each VSim package can be used stand-alone or in combination with one or more other specialty VSim packages. Start with VSim for Basic Physics to model classical physics. Then when you are ready to simulate more advanced physics problems, add the VSim package that does what you need. If you want to simulate electromagnetics in the presence of metallic and dielectric shapes, upgrade to VSim for Electromagnetics. To model RF power systems, add VSim for Microwave Devices. When you are ready to design plasma acceleration experiments, VSim for Plasma Acceleration can provide fast solutions. For plasma discharges, VSim for Plasma Discharges is available to simultaneously simulate kinetic and collisional effects in plasma.

Later, as your need for computational power expands, add more compute cores to your license.

Model Specific Devices or Individual Components

Use VSimMD to design and model:

  • Traveling Wave Tubes (TWTs)
  • Electron guns
  • Striplines
  • Collectors
  • Couplers
  • Magnetrons
  • Klystrons

Simulation examples of devices and components are included with the product, giving you a jump start for creating your own simulations.

Diagnostics from VSim for Microwave Devices provide performance information:

  • Multipacting
  • Operating Modes
  • S-parameters
  • Quality & Geometric Factors
  • Power
  • Voltage
  • Electron Current
  • Electron Tracking
  • Electron Phase-Space

The advanced graphics capability of VSim for Microwave Devices displays detailed profile and particle distribution data.

My group at Boise State University has used VSim extensively and considers it to be an important tool.

In our recent publication (doi: 10.1109/TPS.2018.2844732), we validated VSim by comparing the simulation with experimental results from a crossed-field amplifier, and then used the simulation to study the characteristics of the device with a proposed distributed cathode.

I recommend VSim for anyone designing or studying vacuum electronics devices.

—Prof. Jim Browning, Chair, Electrical & Computer Engineering Boise State University


Geometry and Materials
  • Arbitary geometries with easy construction of complex structures
  • CAD import
  • Variety of pre-defined material types, including copper and stainless steel
  • Customizable materials
  • Partially transparent absorbers
  • Lossfree and lossy, nonlinear, isotropic and anisotropic dielectrics
  • Second-order dispersive dielectrics
  • Excitation with port modes, discrete elements, and discrete face ports
  • Plane waves with elliptical polarization
  • Full field/scattered field
  • Waveguide Ports
  • Unidirectional, and other current-based Ampere-Law sources
  • Circuit equations
  • Adjustable Cerenkov noise filter
Particle Features
  • Surface emission
  • Electron-induced electron emission
  • Controlled emission
  • Field-scaled particles
  • Space-charge limited emission
  • Thermionic emission
  • Secondary Emitter Particle Source for collector analysis
  • Dynamic particle weight settings
  • Particle Sinks
Field and Radiation Features
  • Field emission
  • Fowler-Nordheim emission
  • Laser-induced emission
  • Prescribed emission
  • Analytic and importable Static Magnetic Field capability
  • Feedback control
  • Embedded boundaries for accurate metallic walls
  • Port boundaries: ingoing and outgoing
  • Absorbing and reflecting boundaries
    • Perfectly Matched Layer (PML) boundaries
    • Matched Absorbing Layers (MAL) boundaries
  • Periodic and phase-shifted boundary conditions
  • Dey-Mittra cut-cell algorithm
  • Resistive Wall-loss calculation
Data Analysis
  • Mode calculations using frequency extraction
  • Field and Particle Histories and Feedback
  • Phase-space analysis
  • Particle tracking
Advanced Features
  • General framework for both standard emission types and user-customized emission types
  • Easily parameterized geometries for parameter sweeping and optimization
  • Variable mesh in all coordinate systems grid conforming to custom geometry
  • Detailed particle physics with more algorithms than other simulation tools
  • Availability of non-proprietary output formats that you control, enabling you to access your data with public domain software, Matlab, or your own favorite tool
  • Ability to work from device examples similar to your own device
  • Powerful post-processing capabilities
  • Economical: Use VSimMD as a standalone simulation tool or add advanced physics features as needed by including other VSim packages
  • Easy learning curve: Build your own simulations using built-in examples as a starting point
  • Scales to solve your largest problems. Accurate parallel decomposition for fast solutions
  • Superior customer support by world-class experts



Example Simulations Included

These example problems that demonstrate S-matrix trajectories, thermionic and photo field emission, multipactor saturation are included with VSim for Microwave Devices to jumpstart finding the solution to your problem:

Examples Using Visual Setup

Visual Setup Examples are ready to run and easy to use.  Running a Visual Setup Example and then customizing the settings for your own simulation is the fastest way to learn VSim.

Cavities and Waveguides
Radiation Generation

Examples Using Text Setup

Code your simulation, then run it.  Text Setup Examples demonstrate how to format a simulation input file using code syntax. If you like the level of control available through designing your simulation using VSim code blocks and Python, try using a Text Setup file as the basis for your simulation project.

Cavities and Waveguides
Radiation Generation



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VSim helix twt model
Helix TWT

Helix TWTs, which are used for communications, employ a helical slow wave structure which slows the field down to match the beam velocity as this Vorpal example illustrates.

VSim magnetron simulation showing Bz component

Rising Sun Magnetron

Rising sun magnetron shows a strong pi mode operation in this VSimMD example.

VSim multipacting model


Estimate multipacting threat with enhanced features that look across the entire range of field strengths at once.

VSim model of the center of a two cavity klystron
Two Cavity Klystron

This example shows a simple two cavity klystron amplifier.


VSim magnetron geometry

Magnetron Geometry

VSim model of superconducting (crab) cavities for accelerators

Superconducting Cavities Used for Accelerators

Visualization of Fermilab's A15 crab cavity shows the electric field lines in green, and the magnetic field lines in red.  The magnetic field strength at the wall is shown by color map with the the largest field strengths in orange and the smallest in blue.  The pipes extending from the end wall are for measuring.

VSim magnetron particles simulation
Magnetron 2D Particles



VSim S matrix model


S-matrix dual mode cavity.

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