dielectric

Dielectric material for use as substrate

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    Description

    Dielectric material used as a substrate in PCB components.

    Creation

    Syntax

    d = dielectric(material)
    d = dielectric(material1,...,materialN)
    d = dielectric(PropertyName=Value)

    Description

    d = dielectric(material) returns a dielectric object of the dielectric material for use as a substrate in PCB components.

    d = dielectric(material1,...,materialN) returns a dielectric object of the specified dielectric materials.

    d = dielectric(PropertyName=Value) returns dielectric materials based on the properties specified by one or more name-value pair arguments.

    example

    Input Arguments

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    Material from the dielectric catalog, specified as one of the values from the DielectricCatalog.

    Example: "FR4"

    Data Types: string | char | cell

    Properties

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    Name of the dielectric material you want to specify in the output, specified as a character vector or string.

    Example: Name="Taconic_TLC"

    Data Types: char | cell | string

    Relative permittivity of the dielectric material, specified as a real-valued vector.

    Example: EpsilonR=4.8000

    Data Types: double

    Loss in the dielectric material, specified as a vector.

    Example: LossTangent=0.0260

    Data Types: double

    Thickness of the dielectric material in meters along default z-axis, specified as a positive vector.

    Example: Thickness=0.05

    Data Types: double

    Specified frequency in Hz.

    Example: Frequency = 200e6

    Data Types: double

    For frequency dependent dielectrics use FrequencyModel specified as a dispersion model value:

    • Constant for frequency independent dispersion model

    • DjordjevicSarkar to use the Djordjevic-Sarkar dispersion model

    • MeanDjordjevicSarkar to use the average value of the Djordjevic-Sarkar model over the frequency range of interest

    • TableDriven to use tabular data of dispersion vs. frequency.

    Example: d = dilectric("Name","FR4","FrequencyModel","DjordjevicSarkar")

    Data Types: string

    Object Functions

    getMaterialPropertiesGet material properties of dielectric

    Examples

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    Open Live Script

    Create a PCB stripline having frequency dependent FR4 dielectric substrate using a Djordjevic-Sarkar dispersion model.

    Create a PCB stripline object

    Use stripLine from the RF PCB component catalog and design it at a frequency of 1 GHz

    p = design(stripLine(Substrate=dielectric("FR4"),Conductor=metal('Copper')),1e9);

    Update the frequency dependent dielectric

    Update the dielectric substrate to use the Djordjevic-Sarkar dispersion model.

    p.Substrate.FrequencyModel = 'DjordjevicSarkar';
p.Substrate
    ans = 
  dielectric with properties:

              Name: 'FR4'
          EpsilonR: 4.8000
       LossTangent: 0.0260
         Thickness: 0.0060
         Frequency: 100000000
    FrequencyModel: 'DjordjevicSarkar'

For more materials see catalog

    Calculate s parameters

    Turn off expected warnings:

    warning('off','antenna:emcatalog:PartialFeedLocationsConversion01')
warning('off','rfpcb:rfpcberrors:FailureTraceType')

    Calculate the S-parameters using the sparameters function over a frequency range of 1.01 MHz to 200 GHz using the 2-D Field Solver

    p3D = pcbComponent(p);
p3D.FeedFormat = "FeedLocations";
p2D = slice(p3D);
p2D.Layers{5}.Type = "Ground";
freq = [1.01e3 linspace(1.1e3,200e9,2000)];
s_pcb2D_ds = sparameters(p2D,freq,LineLength=p.Length);

    Reset the state of expected warnings to 'on':

    warning('on','rfpcb:rfpcberrors:FailureTraceType')
warning('on','antenna:emcatalog:PartialFeedLocationsConversion01')

    Calculate S-parameters for no frequency disperson in dielectric.

    p2D.Layers{2}.FrequencyModel = "Constant";
s_pcb2D_c = sparameters(p2D,freq,LineLength=p.Length);

    Plot the S-parameters and impulse response

    Plot the magnitude of the S-parameters over the frequency range

    rfplot(s_pcb2D_ds)

    Figure contains an axes object. The axes object with xlabel Frequency (GHz), ylabel Magnitude (dB) contains 4 objects of type line. These objects represent dB(S_{11}), dB(S_{21}), dB(S_{12}), dB(S_{22}).

    Plot the impulse response of the stripline to see the effect of frequency dispersion.

    ts = 0.95/(2*max(freq));
n = round(4e-10/ts);
fit_ds = rational(s_pcb2D_ds);
[resp_ds,t_ds] = impulse(fit_ds,ts,n);
fit_c = rational(s_pcb2D_c);
[resp_c,t_c] = impulse(fit_c,ts,n);
figure
plot(t_ds{2,1},resp_ds{2,1},'-o',t_c{2,1},resp_c{2,1},'-rx')
xlabel('t[s]')
ylabel('V_{out}[V]')
title('Impulse response of a stripline produced on FR-4')
ylim([-2 12]*1e10)
legend('DjordjevicSarkar','Constant')

    Figure contains an axes object. The axes object with title Impulse response of a stripline produced on FR-4, xlabel t[s], ylabel V indexOf out baseline [V] contains 2 objects of type line. These objects represent DjordjevicSarkar, Constant.

    References

    [1] Djordjevic, D., Biljic, R., Likar-Smiljanic, V., Sarker,T., Wideband Frequency-Domain Characterization of FR-4 and Time-Domain Causality IEEE Transactions on Electromagnetic Compatibility, Vol. 43, No. 4, November 2001

    Version History

    Introduced in R2016a

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    See Also