dielectric

Dielectric material for use as substrate

Syntax

d = dielectric(material)

d = dielectric(Name,Value)

Description

d = dielectric(material) returns dielectric materials for use as a substrate in antenna elements.

d = dielectric(Name,Value) returns dielectric materials, based on the properties specified by one or more Name,Value pair arguments.

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]
                 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]
                 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 properties of air and teflon dielectrics use 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',[.002 .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 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 1GHz.

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 excitor and FR4 as the substrate.

rf = design(reflector,1e9);
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)

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

Example: 'FR4'

Data Types: char

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'Name','Air'

'Name' — Name of dielectric material

character vector

Name of the dielectric material you want to specify in the output, specified as the comma-separated pair consisting of 'Name' and a character vector.

Example: 'Name','Taconic_TLC'

Data Types: char

'EpsilonR' — Relative permittivity of dielectric material

1 | vector

Relative permittivity of the dielectric material, specified as the comma-separated pair consisting of 'EpsilonR' and vector.

Example: 'EpsilonR',4.8000

Data Types: double

'LossTangent' — Loss in dielectric material

0 (default) | vector

Loss in the dielectric material, specified as the comma-separated pair consisting of 'LossTangent' and vector.

Example: 'LossTangent',0.0260

Data Types: double

Note

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

'Thickness' — Thickness of dielectric material

0.0060 (default) | vector in meters

Thickness of the dielectric material along default z-axis, specified as the comma-separated pair consisting of 'Thickness' and vector in meters. This property applies only when you call the function with no output arguments.

Example: 'Thickness', 0.05

Data Types: double

Output Arguments

d — Dielectric material

object handle

Dielectric material, returned as an object handle. You can use the dielectric material object handle to add dielectric material to an antenna.