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dielectric

Dielectric material to use as antenna substrate

    Description

    Dielectric material used as a substrate for antennas.

    Creation

    Description

    d = dielectric(material) creates a dielectric object with pre-defined materials from the dielectric catalog. You can specify a single or multiple dielectric materials from the catalog. Use this dielectric object as a substrate in antenna objects.

    example

    d = dielectric(PropertyName=Value) creates a custom dielectric material based on the properties specified using one or more name–value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify, retain their default values.

    For example, d = dielectric(Name="CustomDielectric",EpsilonR=4.5,LossTangent=0.02,Thickness=1e-3) creates a custom dielectric material of 1mm. thickness with relative permittivity of 4.5, and loss tangent of 0.02.

    example

    Input Arguments

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    Material from the dielectric catalog, specified as a single string for a single material or comma separated strings for multiple materials. You can choose any dielectric material with pre-defined properties from the dielectric catalog. When you specify multiple dielectric materials, dielectric object combines them into a single layer with a default total thickness. You then specify the thickness of individual materials to use this multi-material layer as an antenna substrate. You can also create an array of dielectric materials.

    Example: dielectric("FR4") creates a single dielectric layer of FR4 material.

    Example: dielectric("FR4","Teflon") creates a dielectric layer made of FR4 and Teflon material.

    Example: [dielectric("FR4") dielectric("Teflon")] creates a 1-by-2 dielectric array of FR4 and Teflon materials.

    Data Types: string

    Properties

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    Name of the dielectric material, specified as a string for single material or a cell array of strings for multiple materials.

    Example: "Taconic_TLC"

    Example: {"FR4" "Teflon"}

    Data Types: string

    Relative permittivity of the dielectric material, specified as a positive scalar for a single dielectric material or a positive vector for multiple dielectric materials.

    Example: 4.8000

    Example: [4.8 6.5]

    Data Types: double

    Loss in the dielectric material, specified as a positive scalar for a single dielectric material or a positive vector for multiple dielectric materials.

    Note

    In the Antenna Toolbox™, the upper limit to loss tangent value is 0.03.

    Example: 0.0260

    Example: [0.026 0.028]

    Data Types: double

    Thickness of the dielectric material along z-axis, specified as a positive scalar or positive vector in meters. Specify scalar value for single dielectric material and vector value for multiple dielectric materials.

    Example: 0.05

    Example: [1e-3 2e-3]

    Data Types: double

    Analysis frequency for dispersion models, specified as a positive vector in Hz.

    Example: 200e6

    Data Types: double

    Frequency dispersion model for dielectric material, specified as a string. The default frequency model is Constant. Other supported frequency models are as below:

    • Frequency independent: Constant

    • Frequency dependent: DjordjevicSarkar, MeanDjordjevicSarkar, and TableDriven.

    The DjordjevicSarkar model uses extrapolation techniques to predict properties of dielectric materials over a wide frequency range from a single frequency point measurement. The MeanDjordjevicSarkar model uses average value of the DjordjevicSarkar model over a frequency range of interest to predict properties of dielectric materials. The TableDriven model uses a rational fit on the data provided for dielectric material properties. Use the frequency independent model for narrow band applications. Use the frequency dependent models for wideband applications.

    Example: "DjordjevicSarkar"

    Data Types: string

    Object Functions

    getMaterialPropertiesCalculate dielectric properties of material

    Examples

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    Use a Teflon dielectric material as a substrate for a PIFA antenna. View the antenna.

    d = dielectric("Teflon")
    d = 
      dielectric with properties:
    
                  Name: 'Teflon'
              EpsilonR: 2.1000
           LossTangent: 2.0000e-04
             Thickness: 0.0060
        FrequencyModel: 'Constant'
    
    For more materials see catalog
    
    
    p = pifa(Height=0.0060,Substrate=d)
    p = 
      pifa with properties:
    
                   Length: 0.0300
                    Width: 0.0200
                   Height: 0.0060
                Substrate: [1×1 dielectric]
        GroundPlaneLength: 0.0360
         GroundPlaneWidth: 0.0360
        PatchCenterOffset: [0 0]
            ShortPinWidth: 0.0200
               FeedOffset: [-0.0020 0]
                Conductor: [1×1 metal]
                     Tilt: 0
                 TiltAxis: [1 0 0]
                     Load: [1×1 lumpedElement]
    
    
    show(p)

    Figure contains an axes object. The axes object with title pifa antenna element, xlabel x (mm), ylabel y (mm) contains 4 objects of type patch, surface. These objects represent PEC, feed, Teflon.

    Create a patch microstrip antenna using a substrate with a relative permittivity of 2.70, a loss tangent of 0.002 and a thickness of 0.0008 m. View the antenna.

    t = dielectric(Name="Taconic_TLC",EpsilonR=2.70,LossTangent=0.002,...
         Thickness=0.0008);
    p = patchMicrostrip(Height=0.0008,Substrate=t)
    p = 
      patchMicrostrip with properties:
    
                   Length: 0.0750
                    Width: 0.0375
                   Height: 8.0000e-04
                Substrate: [1×1 dielectric]
        GroundPlaneLength: 0.1500
         GroundPlaneWidth: 0.0750
        PatchCenterOffset: [0 0]
               FeedOffset: [-0.0187 0]
                Conductor: [1×1 metal]
                     Tilt: 0
                 TiltAxis: [1 0 0]
                     Load: [1×1 lumpedElement]
    
    
    show(p)

    Figure contains an axes object. The axes object with title patchMicrostrip antenna element, xlabel x (mm), ylabel y (mm) contains 6 objects of type patch, surface. These objects represent PEC, feed, Taconic_TLC.

    Create a microstrip patch antenna.

    p = patchMicrostrip;

    For property values of air and teflon dielectrics, refer Dielectric Catalog.

    openDielectricCatalog

    Figure Dielectric Materials contains objects of type uimenu, uitoolbar, uitable.

    Use Teflon as a dielectric substrate. There is an air gap between the patch groundplane and the dielectric.

    sub = dielectric(Name=["Air" "Teflon"],EpsilonR=[1 2.1],...
         Thickness=[0.002 0.004],LossTangent=[0 2e-04]);

    Add the substrate to the patch antenna.

    p.Substrate = sub;
    figure
    show(p)

    Figure contains an axes object. The axes object with title patchMicrostrip antenna element, xlabel x (mm), ylabel y (mm) contains 7 objects of type patch, surface. These objects represent PEC, feed, Teflon.

    Create a microstrip patch antenna.

    p = patchMicrostrip;

    For dielectric properties, use the Dielectric Catalog.

    openDielectricCatalog

    Figure Dielectric Materials contains objects of type uimenu, uitoolbar, uitable.

    Use FR4, Teflon and Foam as the three layers of the substrate.

    sub = dielectric(Name=["FR4" "Teflon" "Foam"],EpsilonR=...
        [4.80 2.10 1.03],Thickness=[0.002 0.004 0.001],...
        LossTangent=[0.0260 2e-04 1.5e-04]);

    Add the three layer substrate to the patch antenna.

    p.Substrate = sub;
    figure
    show(p)

    Figure contains an axes object. The axes object with title patchMicrostrip antenna element, xlabel x (mm), ylabel y (mm) contains 8 objects of type patch, surface. These objects represent PEC, feed, FR4, Teflon, Foam.

    Plot the radiation pattern of the antenna.

    figure
    pattern(p,1.67e9)

    Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 8 objects of type patch, surface. These objects represent FR4, Teflon, Foam. Hidden axes object 2 contains 17 objects of type surface, line, text, patch. These objects represent FR4, Teflon, Foam.

    Design a dipole antenna backed by a dielectric substrate and an infinite reflector.

    Create a dipole antenna of length, 0.15 m, and width, 0.015 m.

    d = dipole(Length=0.15,Width=0.015,Tilt=90,TiltAxis=[0 1 0]);

    Create a reflector using the dipole antenna as an exciter and the dielectric, teflon as the substrate.

    t = dielectric("Teflon")
    t = 
      dielectric with properties:
    
                  Name: 'Teflon'
              EpsilonR: 2.1000
           LossTangent: 2.0000e-04
             Thickness: 0.0060
        FrequencyModel: 'Constant'
    
    For more materials see catalog
    
    
    rf = reflector(Exciter=d,Spacing=7.5e-3,Substrate=t);

    Set the groundplane length of the reflector to inf. View the structure.

    rf.GroundPlaneLength = inf;
    show(rf)

    Figure contains an axes object. The axes object with title dipole over infinite ground plane, xlabel x (mm), ylabel y (mm) contains 5 objects of type patch, surface. These objects represent PEC, feed, Teflon, infinite ground.

    Calculate the radiation pattern of the antenna at 70 MHz.

    pattern(rf,70e6)

    Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 5 objects of type patch, surface. These objects represent Teflon, infinite ground. Hidden axes object 2 contains 17 objects of type surface, line, text, patch. These objects represent Teflon, infinite ground.

    Compare the gain values of a dipole antenna in free space and dipole antenna on a substrate.

    Design a dipole antenna at a frequency of 1 GHz.

    d = design(dipole,1e9);
    l_by_w = d.Length/d.Width;
    d.Tilt = 90;
    d.TiltAxis = [0 1 0];

    Plot the radiation pattern of the dipole in free space at 1 GHz.

    figure
    pattern(d,1e9);

    Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 3 objects of type patch, surface. Hidden axes object 2 contains 17 objects of type surface, line, text, patch.

    Use FR4 as the dielectric substrate.

    t = dielectric("FR4")
    t = 
      dielectric with properties:
    
                  Name: 'FR4'
              EpsilonR: 4.8000
           LossTangent: 0.0260
             Thickness: 0.0060
        FrequencyModel: 'Constant'
    
    For more materials see catalog
    
    
    eps_r = t.EpsilonR;
    lambda_0 = physconst("lightspeed")/1e9;
    lambda_d = lambda_0/sqrt(eps_r);

    Adjust the length of the dipole based on the wavelength.

    d.Length = lambda_d/2;
    d.Width = d.Length/l_by_w;

    Design a reflector at 1 GHz with the dipole as the exciter and FR4 as the substrate.

    rf = reflector(Exciter=d,Spacing=7.5e-3,Substrate=t);
    rf.GroundPlaneLength = lambda_d;
    rf.GroundPlaneWidth = lambda_d/4;
    figure
    show(rf)

    Figure contains an axes object. The axes object with title reflector antenna element, xlabel x (mm), ylabel y (mm) contains 6 objects of type patch, surface. These objects represent PEC, feed, FR4.

    Remove the groundplane for plotting the gain of the dipole on the substrate.

    rf.GroundPlaneLength = 0;
    show(rf)

    Figure contains an axes object. The axes object with title reflector antenna element, xlabel x (mm), ylabel y (mm) contains 4 objects of type patch, surface. These objects represent PEC, feed, FR4.

    Plot the radiation pattern of the dipole on the substrate at 1 GHz.

    figure
    pattern(rf,1e9);

    Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 4 objects of type patch, surface. This object represents FR4. Hidden axes object 2 contains 17 objects of type surface, line, text, patch. This object represents FR4.

    Compare the gain values.

    • Gain of the dipole in free space = 2.11 dBi

    • Gain of the dipole on substrate = 1.93 dBi

    Version History

    Introduced in R2016a

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