dielectric

Create dielectric material to use as antenna substrate

Syntax

d = dielectric(material)

d = dielectric(Name=Value)

Description

d = dielectric(material) creates a dielectric object with a pre-defined material from the dielectric catalog. Use this dielectric object as a substrate in antenna objects.

d = dielectric(Name=Value) creates a custom dielectric material, with properties specified by one or more name-value arguments.

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.

Examples

PIFA Antenna with Dielectric Substrate

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

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: [1x1 dielectric]
    GroundPlaneLength: 0.0360
     GroundPlaneWidth: 0.0360
    PatchCenterOffset: [0 0]
        ShortPinWidth: 0.0200
           FeedOffset: [-0.0020 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(p)

Custom Dielectric Properties

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: [1x1 dielectric]
    GroundPlaneLength: 0.1500
     GroundPlaneWidth: 0.0750
    PatchCenterOffset: [0 0]
           FeedOffset: [-0.0187 0]
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(p)

Patch Antenna with Air Gap between Groundplane and Dielectric

Create a microstrip patch antenna.

p = patchMicrostrip;

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

openDielectricCatalog

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)

Three Layer Dielectric Substrate between Patch and Ground Plane

Create a microstrip patch antenna.

p = patchMicrostrip;

For dielectric properties, use the Dielectric Catalog.

openDielectricCatalog

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)

Plot the radiation pattern of the antenna.

figure
pattern(p,1.67e9)

Infinite Reflector Backed Dielectric Substrate Antenna

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

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)

Calculate the radiation pattern of the antenna at 70 MHz.

pattern(rf,70e6)

Antenna On Dielectric Substrate - Compare Gain Values

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);

Use FR4 as the dielectric substrate.

t = dielectric("FR4")

t = 
  dielectric with properties:

           Name: 'FR4'
       EpsilonR: 4.8000
    LossTangent: 0.0260
      Thickness: 0.0060

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)

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

rf.GroundPlaneLength = 0;
show(rf)

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

figure
pattern(rf,1e9);

Compare the gain values.

• Gain of the dipole in free space = 2.11 dBi

• Gain of the dipole on substrate = 1.93 dBi

Input Arguments

material — Material from dielectric catalog

"Air" (default) | string scalar | comma separated strings

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 function 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

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: Name="Air"

Name — Name of dielectric material

string (default) | cell array

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

EpsilonR — Relative permittivity of dielectric material

1 (default) | positive scalar | positive vector

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

LossTangent — Loss in dielectric material

0 (default) | positive scalar | positive vector

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 — Thickness of dielectric material

0.0060 (default) | positive scalar | positive vector

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

Output Arguments

d — Dielectric material

dielectric object

Dielectric material, returned as a dielectric object. You can use this object to set the Substrate property of antenna objects.

Version History

Introduced in R2016a