openEMS

class openEMS.openEMS

This class is the main control class for the FDTD options and setup and to run the final simulation.

Examples

>>> CSX = CSXCAD.ContinuousStructure()
>>>
>>> grid = CSX.GetGrid()
>>> grid.SetLines('x', np.arange(-50,50,1))
>>> grid.SetLines('y', np.arange(-50,50,1))
>>> grid.SetLines('z', np.arange(-2,2.1,1))
>>> grid.SetDeltaUnit(1e-3)
>>>
>>> FDTD = openEMS(NrTS=1e4, EndCriteria=1e-4)
>>>
>>> FDTD.SetCSX(CSX)
>>> FDTD.SetBoundaryCond(['PML_8', 'PML_8', 'PML_8', 'PML_8', 'PEC', 'PEC'])
>>> FDTD.SetGaussExcite(0, 10e9)
>>>
>>> FDTD.AddLumpedPort(port_nr=1, R=50, start=[10, 0, -2], stop=[10, 0, 2], p_dir='z', excite=1)
>>>
>>> FDTD.Run(sim_path='/tmp/test')
Parameters:

  • NrTS – max. number of timesteps to simulate (e.g. default=1e9)

  • EndCriteria – end criteria, e.g. 1e-5, simulations stops if energy has decayed by this value (<1e-4 is recommended, default=1e-5)

  • MaxTime – max. real time in seconds to simulate

  • OverSampling – nyquist oversampling of time domain dumps

  • CoordSystem – choose coordinate system (0 Cartesian, 1 Cylindrical)

  • MultiGrid – define a cylindrical sub-grid radius

  • TimeStep – force to use a given timestep (dangerous!)

  • TimeStepFactor – reduce the timestep by a given factor (>0 to <=1)

  • TimeStepMethod – 1 or 3 chose timestep method (1=CFL, 3=Rennigs (default))

  • CellConstantMaterial – set to 1 to assume a material is constant inside a cell (material probing in cell center)

AddEdges2Grid(primitives, dirs, **kw)

Add the edges of the given primitives to the FDTD grid.

Parameters:

  • dirs – primitives – one or more primitives

  • dirs – str – ‘x’,’y’,’z’ or ‘xy’, ‘yz’ or ‘xyz’ or ‘all’

AddLumpedPort(port_nr, R, start, stop, p_dir, excite=0, **kw)

Add a lumped port with the given values and location.

See also

openEMS.ports.LumpedPort
AddMSLPort(port_nr, metal_prop, start, stop, prop_dir, exc_dir, excite=0, **kw)

Add a microstrip transmission line port.

See also

openEMS.ports.MSLPort
AddRectWaveGuidePort(port_nr, start, stop, p_dir, a, b, mode_name, excite=0, **kw)

Add a rectilinear waveguide port.

See also

openEMS.ports.RectWGPort
AddWaveGuidePort(self, port_nr, start, stop, p_dir, E_func, H_func, kc, excite=0, **kw)

Add a arbitrary waveguide port.

See also

openEMS.ports.WaveguidePort
CreateNF2FFBox(name='nf2ff', start=None, stop=None, **kw)

Create a near-field to far-field box.

This method will automatically adept the recording box to the current FDTD grid and boundary conditions.

See also

openEMS.nf2ff.nf2ff

Notes

  • Make sure the mesh grid and all boundary conditions are finially defined.

GetCSX()
Run(sim_path, cleanup=False, setup_only=False, verbose=None)

Run the openEMS FDTD simulation.

Parameters:

  • sim_path – str – path to run in and create result data

  • cleanup – bool – remove existing sim_path to cleanup old results

  • setup_only – bool – only perform FDTD setup, do not run simulation

  • verbose – int – set the openEMS verbosity level 0..3

Additional keyword parameter: :param numThreads: int – set the number of threads (default 0 –> max)

SetAbort()
SetBoundaryCond(BC)

Set the boundary conditions for all six FDTD directions.

Options:

  • 0 or ‘PEC’ : perfect electric conductor (default)

  • 1 or ‘PMC’ : perfect magnetic conductor, useful for symmetries

  • 2 or ‘MUR’ : simple MUR absorbing boundary conditions

  • 3 or ‘PML-8’ : PML absorbing boundary conditions

Parameters:

BC – (8,) array or list – see options above

SetCSX(CSX)

Set the CSXCAD Continuous Structure for CAD data handling.

See also

CSXCAD.ContinuousStructure
SetCellConstantMaterial(val)

Set cell material averaging to assume constant material inside each primary cell. (Advanced option)

Parameters:

val – bool – Enable or Disable (default disabled)

SetCoordSystem(val)

Set the coordinate system. 0 –> Cartesian (default), 1 –> cylindrical

SetCylinderCoords()

Enable use of cylindircal coordinates.

See also

openEMS.SetMultiGrid
SetDiracExcite(f_max)

Set a dirac pulse as excitation signal.

Parameters:

f_max – float – maximum simulated frequency in Hz.

SetEndCriteria(val)

Set the end criteria value. E.g. 1e-6 for -60dB

SetGaussExcite(f0, fc)

Set a Gaussian pulse as excitation signal.

Parameters:

  • f0 – float – Center frequency in Hz.

  • fc – float – -20dB bandwidth in Hz.

SetMaxTime(val)

Set max simulation time for a max. number of timesteps.

SetMultiGrid(radii)

Define radii at which a cylindrical multi grid should be defined.

Parameters:

radii – array like, multigrid radii

See also

openEMS.SetCylinderCoords
SetNumberOfTimeSteps(val)

Set the number of timesteps. E.g. 5e4 (default is 1e9)

SetOverSampling(val)

Set the time domain signal oversampling as multiple of the Nyquist-rate.

SetSinusExcite(f0)

Set a sinusoidal signal as excitation signal.

Parameters:

f0 – float – frequency in Hz.

SetStepExcite(f_max)

Set a step function as excitation signal.

Parameters:

f_max – float – maximum simulated frequency in Hz.

SetTimeStep(val)

Set/force the timestep. (Advanced option)

It is highly recommended to not use this method! You may use the SetTimeStepFactor instead to reduce the time step if necessary!

SetTimeStepFactor(val)

Set a time step factor (>0..1) to increase FDTD stability.

Parameters:

val – float – >0..1

SetTimeStepMethod(val)

Set the time step calculation method. (Advanced option)

Options:

  • 1: CFL criteria

  • 3: Advanced Rennings criteria (default)

Parameters:

val – int – 1 or 3 (See above)

static WelcomeScreen()

Show the openEMS welcome screen.