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Component or network from file data


Use the datafile object to represent RF components and networks that are characterized by measured or simulated data in a file.

Use the read method to read the data from a file in one of the following formats:

  • Touchstone

  • Agilent® P2D

  • Agilent S2D

  • AMP


sparameters is recommend over rfdata.datafile because it enables you to calculate S-parameters for RF data, network, circuit, and matching network objects. (since R2023b)




h = rfckt.datafile returns a circuit object whose properties all have their default values.

h = rfckt.datafile(Name,Value) sets properties using one or more name-value pairs. For example, rfckt.datafile('IntType','Cubic') creates an RF component or network that uses cubic interpolation. You can specify multiple name-value pairs. Enclose each property name in a quote. Properties not specified retain their default values.


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This property is read-only.

Computed S-parameters, noise figure, OIP3, and group delay values, specified as a object. For more information refer, Algorithms.

Data Types: function_handle

File name containing circuit data, specified as a 1-by-1 character array.

Data Types: char

Interpolation method, specified as a 1-by-N character array of the following values:

Linear (default)Linear interpolation
SplineCubic spline interpolation
CubicPiecewise cubic Hermite interpolation

Data Types: char

This property is read-only.

Object name, specified as a 1-by-N character array.

Data Types: char

This property is read-only.

Number of ports, specified as a positive integer. The default value is 2.

Data Types: double

Object Functions

analyzeAnalyze RFCKT object in frequency domain
calculateCalculate specified parameters for rfckt objects or rfdata objects
circleDraw circles on Smith Chart
extractExtract specified network parameters from rfckt object or data object
listformatList valid formats for specified circuit object parameter
listparamList valid parameters for specified circuit object
loglogPlot specified circuit object parameters using log-log scale
plotPlot circuit object parameters on X-Y plane
plotyyPlot parameters of RF circuit or RF data on xy-plane with two Y-axes
getopDisplay operating conditions
polarPlot specified object parameters on polar coordinates
semilogxPlot RF circuit object parameters using log scale for x-axis
semilogyPlot RF circuit object parameters using log scale for y-axis
smithPlot circuit object parameters on Smith Chart
writeWrite RF data from circuit or data object to file
getz0Calculate characteristic impedance of RFCKT transmission line object
readRead RF data from file to new or existing circuit or data object
restoreRestore data to original frequencies
getopDisplay operating conditions
groupdelayGroup delay of S-parameter object or RF filter object or RF Toolbox circuit object


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Represent RF components and networks that are characterized by measured or simulated data in a file using rfckt.datafile.

data = 
   rfckt.datafile with properties:

          IntpType: 'Linear'
              File: 'default.s2p'
             nPort: 2
    AnalyzedResult: [1x1]
              Name: 'Data File'


The analyze method computes the AnalyzedResult property using the data stored in the File object property. If the file you specify with this property contains network Y- or Z-parameters, analyze first converts these parameters, as they exist in the rfckt.datafile object, to S-parameters. Using the interpolation method you specify with the 'IntpType' property, analyze interpolates the S-parameters to determine the S-parameters at the specified frequencies. Specifically, analyze orders the S-parameters according to the ascending order of their frequencies, fn. It then interpolates the S-parameters, using the MATLAB® interp1 function. For example, the curve in the following diagram illustrates the result of interpolating the S11 parameters at five different frequencies.

S11 interpolation results

For more information, see “One-Dimensional Interpolation” and the interp1 reference page in the MATLAB documentation.


[1] EIA/IBIS Open Forum, Touchstone File Format Specification, Rev. 1.1, 2002

Version History

Introduced before R2006a