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resonantFrequency

Calculate and plot resonant frequency of antenna

Since R2024a

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    Syntax

    resonantFrequency(object,frequency)
    resonantFrequency(object,frequency,Method="Sparameters")
    resonantFrequency(object,frequency,Method="Impedance",Name=Value)
    resonantFrequency(object,frequency,Method="Sparameters",Name=Value)
    fRES = resonantFrequency(object,frequency)
    fRES = resonantFrequency(object,frequency,Name=Value)
    [fRES,zRES,Z,typRES] = resonantFrequency(object,frequency)
    [fRES,zRES,Z,typRES] = resonantFrequency(object,frequency,Method="Impedance",Name=Value)
    [fRES,sRES,S] = resonantFrequency(object,frequency,Method="Sparameters")
    [fRES,sRES,S] = resonantFrequency(object,frequency,Method="Sparameters",Name=Value)

    Description

    resonantFrequency(object,frequency) marks the resonant frequencies on the impedance plot of the specified antenna or array in the specified frequency range. If no resonant frequency is detected in the specified frequency range, this syntax plots the impedance of the specified antenna or array without any marked points.

    resonantFrequency(object,frequency,Method="Sparameters") marks the resonant frequencies on the S11 plot of the specified antenna or array in the specified frequency range. If no resonant frequency is detected in the specified frequency range, this syntax plots the S11 of the specified antenna or array without any marked points.

    resonantFrequency(object,frequency,Method="Impedance",Name=Value) marks the resonant frequencies on the impedance plot of the specified antenna or array in the specified frequency range with additional options specified by one or more Name-Value Arguments. If no resonant frequency is detected in the specified frequency range, this syntax plots the impedance of the specified antenna or array without any marked points.

    resonantFrequency(object,frequency,Method="Sparameters",Name=Value) marks the resonant frequencies on the S11 plot of the specified antenna or array in the specified frequency range with additional options specified by one or more Name-Value Arguments. If no resonant frequency is detected in the specified frequency range, this syntax plots the S11 of the specified antenna or array without any marked points.

    fRES = resonantFrequency(object,frequency) calculates and returns the resonant frequencies of the specified antenna or array in the specified frequency range. fRES is empty if no resonant frequency is detected in the specified frequency range. fRES is a vector when more than one resonant frequencies are detected in the specified frequency range.

    fRES = resonantFrequency(object,frequency,Name=Value) calculates and returns the resonant frequencies of the specified antenna or array in the specified frequency range using additional options specified by one or more Name-Value Arguments. fRES is empty if no resonant frequency is detected in the specified frequency range. fRES is a vector when more than one resonant frequencies are detected in the specified frequency range.

    [fRES,zRES,Z,typRES] = resonantFrequency(object,frequency) calculates and returns the resonant frequencies fRES and the corresponding impedances zRES and resonance type typRES (series or parallel) for the specified antenna or array in the specified frequency range. fRES, zRES, and typRES are empty if no resonant frequency is detected within the specified frequency range. fRES and zRES are vectors, and typRES is a string array when more than one resonant frequencies are detected. Z is a vector of all the impedance values across the specified frequency range.

    example

    [fRES,zRES,Z,typRES] = resonantFrequency(object,frequency,Method="Impedance",Name=Value) calculates and returns the resonant frequencies fRES and the corresponding impedances zRES and resonance type typRES (series or parallel) for the specified antenna or array in the specified frequency range using additional options specified by one or more Name-Value Arguments. fRES, zRES, and typRES are empty if no resonant frequency is detected within the specified frequency range. fRES and zRES are vectors, and typRES is a string array when there are more than one resonant frequencies. Z is a vector of all the impedance values across the specified frequency range.

    example

    [fRES,sRES,S] = resonantFrequency(object,frequency,Method="Sparameters") calculates and returns the resonant frequencies fRES and the corresponding S11 values sRES for the specified antenna or array in the specified frequency range. fRES and sRES are empty if no resonant frequency is detected within the specified frequency range. fRES and sRES are vectors when more than one resonant frequencies are detected. S is a vector of all the S11 values across the specified frequency range.

    [fRES,sRES,S] = resonantFrequency(object,frequency,Method="Sparameters",Name=Value) calculates and returns the resonant frequencies fRES and the corresponding S11 values sRES for the specified antenna or array in the specified frequency range using additional options specified by one or more Name-Value Arguments. S is a vector of all the S11 values across the specified frequency range.

    Examples

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    Open Live Script

    This example shows how to calculate and plot the resonant frequency of a dipole antenna using Impedance method and S-parameters method.

    Calculate and Plot Resonant Frequency using Impedance Method

    Create a dipole antenna operating at 75 MHz. Calculate and plot the resonant frequency of a dipole over a frequency span of 50 MHz - 100 MHz.

    h = design(dipole,75e6);
resonantFrequency(h,50e6:1e6:100e6);

    Figure contains an axes object. The axes object with title Impedance for dipole, xlabel Frequency (MHz), ylabel Impedance (ohms) contains 6 objects of type line, constantline, scatter. These objects represent Resistance, Reactance, Threshold (+/-15.0 ohms).

    Calculate and Plot Resonant Frequency using S-parameters Method

    Calculate and plot the resonant frequency of the same dipole, using S-parameters method, over the same frequency span.

    resonantFrequency(h,50e6:1e6:100e6,Method="Sparameters");

    Figure contains an axes object. The axes object with title S11 for dipole, xlabel Frequency (MHz), ylabel Magnitude (dB) contains 3 objects of type line, constantline, scatter. These objects represent dB(S_{11}), Threshold (-10.00 dB).

    Input Arguments

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    Antenna or array to calculate resonant frequency, specified as one of the following options:

    Example: dipole

    Frequency range to calculate the resonant frequency, specified as a positive vector in Hertz.

    Example: [50e6:5e6:80e6]

    Data Types: double

    Name-Value Arguments

    Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

    Example: Method="Sparameters"

    Option to enable parallel pool, specified as a logical value. The default value is false. Set this option to true or 1 to enable the parallel pool. Use parallel pool to speedup the resonant frequency calculations at multiple frequencies for computationally large antennas and arrays. To use this feature, you need a license to the Parallel Computing Toolbox™.

    Example: UseParallel=true

    Data Types: logical

    Method to use for resonant frequency calculation, specified as either "Impedance" or "Sparameters". The default method is "Impedance". When the method is specified as "Impedance", zero-crossings of the reactance are used to find the resonant frequency, and zRES and Z are the outputs. When the method is specified as "Sparameters", the negative peaks of S11 are used to find the resonant frequency. The output typRES (whether the impedance is series or parallel) is supported only when the method is "Impedance".

    Example: "Sparameters"

    Data Types: string

    Threshold value for impedance or S11, specified as a real scalar in ohms when the Method is set to "Impedance" or a real scalar in dB when the Method is set to Sparameters.

    Example: -12

    Data Types: double

    Reference impedance to calculate the S-parameters, specified as a positive real scalar in ohms. The default reference impedance is 50 ohms. This argument is valid only when the Method argument is set to Sparameters.

    Example: 75

    Data Types: double

    Option to enable or disable the data tips, specified as a logical true to enable or logical false to disable the data tips. By default, the data tips are enabled.

    Example: Specifying PlotDataTips=false disables the data tips on the plot.

    Data Types: logical

    Output Arguments

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    Resonant frequency in Hz of the specified antenna, returned as either positive scalar value for a single resonance or a positive vector for multiple resonances within the specified frequency sweep.

    Example: 75.33e6

    Impedance values corresponding to the resonant frequencies, returned as a real or complex scalar or vector. zRES is empty when there are no resonant frequencies within the specified frequency range. And zRES is a vector when multiple resonances are found within the specified frequency range.

    Example: 75

    Data Types: double
    Complex Number Support: Yes

    S11 values corresponding to the resonant frequencies, returned as a complex vector in dB.

    Data Types: double
    Complex Number Support: Yes

    Impedance values over entire frequency range, returned as a complex vector in ohms.

    Data Types: double
    Complex Number Support: Yes

    S11 values over the entire frequency range, returned as a complex vector in dB.

    Data Types: double

    Resonance type, returned as a string. The resonance type is either "Series", "Parallel" or "Unclear". When the reactance in the impedance plot approaches zero but does not cross it, resonance type is returned as "Unclear".

    Example: "Parallel"

    Data Types: string

    Version History

    Introduced in R2024a

    See Also

    Functions

    Topics