NetworkParameterExtraction Object
Determine an equivalent SPICE circuit which has the same behaviour at the ports as the simulation model. Two different methods exist for this task. The "transmission line model" (TL) is based on a fixed topology of a network of parallel and coupled transmission lines. The other more general method is based on a "model order reduction" (MOR) and does not assume any fixed topology. The drawback of the latter approach, however, is that the derived SPICE circuit elements do not allow any physical interpretation.
Reset
Resets all internal values to their default settings.
Method ( enum {"TransmissionLine", "MOR"} extractionMethod )
Selects the method to be used when running network parameter extraction.
GetMethod enum {"TransmissionLine", "MOR"}
Returns the currently set method for extracting network parameters.
Calculate
Starts the network parameter extraction with the previously made settings.
Methods for Transmission Line (TL) Based Extraction
AddWire ( long number, long portA, long modeA, long portB, long modeB )
Define a wire element between two ports to obtain the network parameters. The number denotes the number of the wire. The wire starts at port portA (modeA) and ends at port portB (modeB).
Please note: all arguments must be long value here. Any expression is not allowed.
SetFrequency ( double freq )
Defines the extraction frequency for the network parameter model. The calculated network model is most accurate at this frequency.
Please note: freq must be a double value here. Any expression is not allowed.
SetNCascades ( long number )
Defines how many network elements are cascaded to approximate the input/output behavior of the simulated structure.
Please note: number must be a long integer value here. Any expression is not allowed.
SetLimitCoupling ( bool bFlag, double limit )
If activated (bFlag is True) the coupling between wires is limited if a certain minimum coupling value is not reached. Then coupling elements between these wires will be omitted. Enable or disable this behaviour here and set the limit value.
SetKeepTopology ( bool bFlag, double minR, double minG, double minL, double minC, double minK )
if bFlag is True the topology of the extracted network will not be changed even if some elements have values close to 0. Those elements with values lower than a given limit will be set to this limit. Set the limit using the minR, minG, minL, minC and minK parameters. MinR, minG, minL, minC and minK set the limits for the resistance in Ohms, the transconductance in S the inductance in H, the capacitance in F and the couling respectively.
GenerateSubCircuit ( bool bFlag )
If bFlag is True the resulting SPICE netlist of the transmission line based network parameter extraction is enclosed in a sub-circuit. The sub-circuit begins with the ".subckt" statement and ends with the ".ends" statement.
CreateNetList
Creates a netlist file for SPICE simulation after the transmission line based calculation (performed by the method Calculate) has finished.
Queries Concerning Settings for TL
GetNWires long
Returns the number of defined wires
Returns the id of the wire. Index is a number between 0 and n-1, where n is the number of defined wires as returned by GetNWires.
GetWirePortA ( long index ) long
GetWirePortB ( long index ) long
GetWirePortAFromId ( long id ) long
GetWirePortBFromId ( long id ) long
Returns the port number where the wire starts (GetWirePortA) or ends (GetWirePortB) respectively. Index is a number between 0 and n-1, where n is the number of defined wires as returned by GetNWires. Id is the identification number of a wire. It can be determined using the GetWireId method.
GetWireModeA ( long index ) long
GetWireModeB ( long index ) long
GetWireModeAFromId ( long id ) long
GetWireModeBFromId ( long id ) long
Returns the mode number of the port where the wire starts (GetWireModeA) or ends (GetWireModeB) respectively. Index is a number between 0 and n-1, where n is the number of defined wires as returned by GetNWires. Id is the identification number of a wire. It can be determined using the GetWireId method.
GetFrequency double
Returns the extraction frequency for the network parameter model. The calculated network model is most accurate at this frequency.
GetNCascade long
Returns how many cascaded network elements have been used to approximate the input/output behavior of the simulated structure.
Queries Concerning Results for TL
Returns the calculated resistance R, conductance G, or inductance L of the transmission line based network parameter model respectively. It is specified by the identity number id of the corresponding wire.
GetCFromId ( long id1, long id2 ) double
Returns the calculated capacitance C of the transmission line based network parameter model. It is specified by the identity number of the corresponding wires id1 and id2. In case that both identity numbers are identically the self capacitance of the network element results, in case of two different numbers the mutual capacitance between two elements.
GetKFromId ( long id1, long id2 ) double
Returns the calculated mutual inductance K of the transmission line based network parameter model. It is specified by the identity number of the two corresponding wires id1 and id2.
Methods for Model Order Reduction (MOR) Based Extraction
CircuitFileName ( filename fileName )
Sets the filename of the resulting SPICE netlist based on model order reduction to fileName.
GetCircuitFileName filename
Returns the filename of the resulting SPICE netlist based on model order reduction.
EnsureOutOfBandPassivity ( bool bFlag )
If bFlag is True passivity for frequency values out of the given band is ensured, otherwise not.
UseARFilterResults ( bool bFlag )
If this method is activated the MOR method uses S-parameter data based on AR-Filter results if available.
Accuracy ( double value )
Specifies the maximum error value for the S-parameter approximation.
Please note: The accuracy can be violated after performing the passivity step which is activated using the EnsureOutOfBandPassivity method.
InitalNumberOfPoles ( int number )
Specifies the initial number of poles considered by the MOR scheme.
DifferentialNetlist(bool bFlag)
Specifies whether the netlist should be written with differential ports
NetlistFormat(enum {"Berkeley SPICE", "HSPICE"} format)
Specifies the output format of the netlist. "Berkeley SPICE" uses standard Berkeley SPICE notation with controlled sources while "HSPICE" uses Laplace formulation of the fitted Y parameter.
Method ("TransmissionLine")
' defaults for transmission line based network parameter extraction
SetFrequency (0.0)
SetNCascades (1)
SetLimitCoupling (False, 60.0)
SetKeepTopology (False, 1e-30, 1e-30, 1e-30, 1e-30, 1e-30)
GenerateSubCircuit (False)
' defaults for model order reduction based network parameter extraction
EnsureOutOfBandPassivity (True)
UseARFilterResults (False)
Accuracy ("1e-2")
InitalNumberOfPoles (10)
NetlistFormat ("Berkeley SPICE")
' start an transmission line based network extraction
With NetworkParameterExtraction
.Method ("TransmissionLine")
.SetFrequency (0.9)
.SetNCascades (3)
.SetLimitCoupling (True, 30.0)
.SetKeepTopology (False, 1e-30, 1e-30, 1e-30, 1e-30, 1e-30)
.GenerateSubCircuit (True)
.Calculate
End With
' start an MOR based network extraction
With NetworkParameterExtraction
.Method ("MOR")
.CircuitFileName ("my_netlist.net")
.EnsureOutOfBandPassivity (False)
.UseARFilterResults (False)
.Accuracy ("1e-2")
.InitalNumberOfPoles (10)
.DifferentialNetlist (True)
.NetlistFormat ("HSPICE")
.Calculate
End With