dielectric
Create dielectric material to use as antenna substrate
Description
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(material
)
creates a custom dielectric material, with properties specified by one or more
name-value
arguments.d
= dielectric(Name=Value
)
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
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