AC Simulation Task

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This dialog box offers to setup a frequency domain circuit simulation. External ports or voltage or current sources are used to define excitations.

The primary results generated by an AC simulation task are voltage and current curves as a function of the frequency inside the specified range and for the probes contained by your design. These results can be accessed from the navigation tree.

Additionally, equivalent current sources are generated for all blocks that contain a model for EMI analysis generated by CST PCB STUDIO or CST CABLE STUDIO. For CST PCB STUDIO blocks, the current sources are only created if the Export Currents for EMI parameter is checked. These results can be used as a near field source in CST MICROWAVE STUDIO. They are stored in files named (relative to the project folder) Result\DS\Tasks\AC1\Components\PCBSSCHEM1\radiaton.rsd, where AC1 is the task name and PCBSSCHEM1 the name of the block. In addition, CST CABLE STUDIO exports the geometry of the surrounding enclosure to the file Model\CBLS\tlm_settings\tlmodel.nas. These files may be imported as near field sources in CST MICROWAVE STUDIO to perform further radiation calculations of PCB structures or cable harnesses.

Additionally, equivalent field sources are generated for all blocks that contain a model for EMI analysis generated by CST PCB STUDIO and with the Export Currents for EMI parameter checked. These results can be used as a near field source in CST MICROSTRIPES. They are stored in files named (relative to the project folder) Result\DS\Tasks\AC1\Components\PCBSSCHEM1\radiaton_esf.ths, Result\DS\Tasks\AC1\Components\PCBSSCHEM1\radiaton_esf.xvs, Result\DS\Tasks\AC1\Components\PCBSSCHEM1\radiaton_esf.tbs and Result\DS\Tasks\AC1\Components\PCBSSCHEM1\radiaton_esf.rad, where AC1 is the task name and PCBSSCHEM1 the name of the block. These files may be imported as near field sources in CST MICROSTRIPES to perform further radiation calculations of PCB structures.

This dialog box provides the settings for the AC simulation task.

Frequency limits frame

Lower Limit: Shows the lower frequency limit.

Upper Limit: Shows the upper frequency limit.

Units frame

Global units: Use the global frequency unit (that may be defined within the Units dialog box) for this task..

Local units: Select this option to specify a local frequency unit.

Frequencies: Select the local frequency unit here.

AC settings frame

Maximum frequency range: Check this control if you want to use the maximum frequency range given by the lower and upper limit.

Fmin: Specify the lower limit manually.

Fmax: Specify the upper limit manually.

Samples: Specify the number of samples in the frequency range.

Logarithmic sweep: Sweeps the frequency in logarithmic samples

Individual blocks frame

S-parameter interpolation scheme:

The import of results usually requires some data resampling. That resampling implies the application of an interpolation scheme. S-parameter data can be interpolated in one of the two following ways:

Real/Imaginary: Choose this option to interpolate the complex S-parameters by separately interpolating real part and imaginary part. The magnitude and the phase will show some interpolation error then.

Magnitude/Phase: Choose this option to interpolate the complex S-parameters by separately interpolating magnitude and phase. The real and imaginary parts will show some interpolation error then.

Excitation settings frame

Port/Source/Magnitude/Phase: This list displays the excitations specified for the external ports. If an external port is not associated with an excitation, it will be considered as an impedance during the simulation. There are four possible choices for each port:

• ’Voltage’ selects an ideal voltage source with the specified magnitude and phase.

• ’Current’ selects an ideal current source with the specified magnitude and phase.

• ’Signal’ selects a signal source according to the signal definition in CST MICROWAVE STUDIO® with the specified magnitude and phase. The unit of such a signal is √W.

• ’Impedance of port’ selects a magnitude and phase versus ground. The magnitude and phase value is determined by the impedance settings of the external port.

The complex value of each excitation source may be entered as magnitude and phase (in degrees).

OK

Stores the current settings and closes the dialog box.

Cancel

Closes this dialog box without performing any further action.

Apply

Stores the current settings (without closing the dialog box).

Specials...

Shows the Solver Specials Dialog.

Help

Shows this help text.

See also

Simulation Task Overview, Combine Results Simulation Task, CST PCB STUDIO File Block, CST PCB STUDIO Schematic Block, CST MICROWAVE STUDIO/CST CABLE STUDIO File Block, CST MICROWAVE STUDIO/CST CABLE STUDIO Schematic Block