== Running 3D MoM Simulations ==
Once you have set up your structure in EM.Libera, have defined sources and observables and have examined the quality of the structure's mesh, you are ready to run a 3D MoM simulation. EM.Libera offers four types of five simulationmodes (click on each type to learn more about it):
* '''[[#Running a Single-Frequency MoM Analysis| Single-Frequency Analysis]]'''* '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Frequency_Sweep_Simulations_in_EM.Cube | Frequency Sweep]]''' including uniform and adaptive frequency sweeps * '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Parametric_Sweep_Simulations_in_EM.Cube | Parametric Sweep]]'''* '''[[Parametric_Modeling,_Sweep_%26_Optimization#Optimization | Optimization]]'''* '''[[Building_Reusable_Models#Running_an_HDMR_Sweep | HDMR Sweep]]'''
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Parametric_Sweep_Simulations_in_EM.Cube | Running Parametric Sweep Simulations in You can set the simulation mode from EM.Cube]]''Libera's "Simulation Run Dialog". [[Image:Info_iconA single-frequency analysis is a single-run simulation.png|40px]] Click here to learn more about '''[[Parametric_Modeling,_Sweep_%26_Optimization#Optimization | Running Optimization Simulations All the other simulation modes in EMthe above list are considered multi-run simulations.Cube]]'''If you run a simulation without having defined any observables, no data will be generated at the end of the simulation. In multi-run simulation modes, certain [[Image:Info_icon.png|40pxparameters]] Click here to learn more about '''[[Running_HDMR_Simulations_in_EMare varied and a collection of simulation data files are generated.Cube | Running HDMR Simulations At the end of a sweep simulation, you can graph the simulation results in EM.Cube]]'''Grid or you can animate the 3D simulation data from the navigation tree.
=== Running a Single-Frequency MoM Analysis ===
In a single-frequency analysis, the structure of your project workspace is meshed at the center frequency of the project and analyzed by one of EM.Libera's two MoM solvers. If your project contains at lease least one line or curve object, the Wire MoM solver is automatically selected. Otherwise, the Surface MoM solver will always be used to simulate your numerical problem. In either case, the engine type is set automatically.
To open the Run Simulation Dialog, click the '''Run''' [[File:run_icon.png]] button of the '''Simulate Toolbar''' or select '''Menu > Simulate > Run...''' or use the keyboard shortcut {{key|Ctrl+R}}. By default, the Surface MoM solver is selected as your simulation engine. To start the simulation, click the {{key|Run}} button of this dialog. Once the 3D MoM simulation starts, a new dialog called '''Output Window''' opens up that reports the various stages of MoM simulation, displays the running time and shows the percentage of completion for certain tasks during the MoM simulation process. A prompt announces the completion of the MoM simulation.
</tr>
</table>
Â
=== Running Frequency Sweep Simulations in EM.Libera ===
Â
[[Image:wire_pic24.png|thumb|450px| EM.Libera's Frequency Settings dialog.]]
In a frequency sweep simulation, the operating frequency of the project is varied during the simulation, and the frequency response of your structure is computed at each frequency sample. EM.Libera offers two types of frequency sweep: uniform and adaptive. In a uniform sweep, equally spaced frequency samples are generated between the start and end frequencies. In the case of an adaptive sweep, you must specify the '''Maximum Number of Iterations''' as well as the '''Error'''. An adaptive sweep simulation starts with a few initial frequency samples, where the Wire MoM engine is initially run. Then, the intermediate frequency samples are calculated and inserted in a progressive manner. At each iteration, the frequency samples are used to calculate a rational approximation of the scattering parameter response over the specified frequency range. The process stops when the specified error criterion is met in a mean-square sense. The adaptive sweep simulation results are always continuous and smooth. This is due to the fact that a rational function curve is fitted through the discrete frequency data points. This usually captures frequency response characteristics such as resonances with much fewer calculated data points. However, you have to make sure that the process converges. Otherwise, you might get an entirely wrong, but still perfectly smooth, curve at the end of the simulation.
To run a 3D MoM frequency sweep, open the '''Run Simulation Dialog''' and select '''Frequency Sweep''' from the '''Simulation Mode''' dropdown list in this dialog. The '''Settings''' button located next to the simulation mode dropdown list becomes enabled. If you click this button, the Frequency Settings Dialog opens up. First you have to choose the '''Sweep Type''' with two options: '''Uniforms''' or '''Adaptive'''. The default option is a uniform sweep. In the frequency settings dialog, you can set the start and end frequencies as well as the number of frequency samples.
Â
During a frequency sweep, as the project's frequency changes, so does the wavelength. As a result, the mesh of the structure also changes at each frequency sample. The frequency settings dialog gives you three choices regarding the mesh of the project structure during a frequency sweep:
Â
* Fix mesh at the highest frequency.
* Fix mesh at the center frequency.
* Re-mesh at each frequency.
== Working with 3D MoM Simulation Data ==