getRationalModel

R2026b

Read rational fitting parameters

Since R2025a

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    Syntax

    parameters = getRationalModel(sweepobj)

    Description

    parameters = getRationalModel(sweepobj) returns a rational object with read-only properties storing the rational fitting parameters.

    Examples

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    This example uses:

    Open Live Script

    Create a frequency sweep object for using a gradient-based interpolating sweep.

    h = frequencySweep;
h.SweepType = "interpWithGrad";
h.NumFreqs = 200;

    Create a dipole antenna. Calculate its S-parameter in the range 60 MHz to 80 MHz using frequency sweep interpolation.

    d = dipole; 
[s,sweeptype] = sparameters(d,[60e6,80e6],SweepOption=h)
    s = 
  sparameters with properties:

      Impedance: 50
       NumPorts: 1
     Parameters: [1×1×200 double]
    Frequencies: [200×1 double]


    sweeptype = 
  frequencySweep with properties:

    SweepType: "interpWithGrad"
       ErrTol: -80
     NumFreqs: 200
     NumIters: 25

    View rational fit parameters of the interpolated sweep.

    g = getRationalModel(sweeptype)
    g = 
  rational with properties:

      NumPorts: 1
      NumPoles: 5
         Poles: [5×1 double]
      Residues: [1×1×5 double]
    DirectTerm: 0.0947
         ErrDB: -154.4964

    Plot the S-parameter.

    figure
rfplot(s)

    Figure contains an axes object. The axes object with xlabel Frequency (MHz), ylabel Magnitude (dB) contains an object of type line. This object represents dB(S_{11}).

    Input Arguments

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    Frequency sweep interpolation parameters, specified as a frequencySweep (Antenna Toolbox) object.

    Example: sweepobj = frequencySweep; sweepobj.SweepType="interpWithGrad"; parameters = getRationalModel(sweepobj) reads the rational fitting parameters from the sweep object.

    Output Arguments

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    Rational fitting parameters, returned as a rational object.

    Version History

    Introduced in R2025a

    See Also

    Functions

    Objects