Main Content

reflector

Create reflector-backed antenna

expand all in page

Description

The default reflector object is a reflector-backed antenna with a center-fed dipole exciter resonating around 885.7 MHz.

Creation

Syntax

rf = reflector
rf = reflector(Name=Value)

Description

rf = reflector creates a reflector backed antenna having center-fed dipole exciter with default property values. The default dimensions are chosen for an operating frequency of around 885.7 MHz.

rf = reflector(Name=Value) sets propertiesusing one or more name-value arguments. Name is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as Name1=Value1,...,NameN=ValueN. Properties that you do not specify, retain their default values.

For example, r = reflector(Exciter=yagiUda) creates a reflector antenna with a Yagi Uda as an exciter.

example

Properties

expand all

Exciter antenna or array type, specified as either:

  • Antenna object from the catalog (except reflector type, cavity type and platform-installed antennas)

  • Array object from the catalog (except conformal and infinite arrays)

  • Custom antennas: customAntennaGeometry, customAntennaMesh, customAntenna

  • Empty array

To create the reflector backing structure without an exciter, specify this property as an empty array.

Example: horn

Example: linearArray(Element=patchMicrostrip)

Example: customAntenna

Example: []

Substrate dielectric material, specified as "air" or a dielectric object. For more information about dielectric substrate meshing, see Meshing.

Note

The substrate dimensions must be equal to the groundplane dimensions.

Example: dielectric("FR4")

Reflector length along the x-axis, specified a scalar in meters. By default, ground plane length is measured along the x-axis. Setting GroundPlaneLength toInf, uses the infinite ground plane technique for antenna analysis. You can also set the GroundPlaneLength to zero.

Example: 3

Data Types: double

Reflector width along the y-axis, specified as a scalar in meters. By default, ground plane width is measured along the y-axis. Setting GroundPlaneWidth toInf, uses the infinite ground plane technique for antenna analysis. You can also set the GroundPlaneWidth to zero.

Example: 2.5

Data Types: double

Distance between the reflector and the exciter, specified as a scalar in meters. By default, the exciter is placed along the x-axis.

Example: 7.5e-2

Data Types: double

Type of the metal used as a conductor, specified as a metal material object. You can choose any metal from the MetalCatalog or specify a metal of your choice. For more information, see metal. For more information on metal conductor meshing, see Meshing.

Example: metal("Copper")

Lumped elements added to the antenna feed, specified as a lumped element object. For more information, see lumpedElement.

Example: Load=lumpedelement. lumpedelement is the object for the load created using lumpedElement.

Example: lumpedElement(Impedance=75)

Create probe feed from backing structure to exciter, specified as 0 (disable) or 1 (enable). By default, probe feed is disabled.

Example: 1

Data Types: double | logical

Tilt angle of the antenna in degrees, specified as a scalar or vector. For more information, see Rotate Antennas and Arrays.

Example: 90

Example: Tilt=[90 90],TiltAxis=[0 1 0;0 1 1] tilts the antenna at 90 degrees about the two axes defined by the vectors.

Data Types: double

Tilt axis of the antenna, specified as one of these values:

  • Three-element vector of Cartesian coordinates in meters. In this case, each coordinate in the vector starts at the origin and lies along the specified points on the x-, y-, and z-axes.

  • Two points in space, specified as a 2-by-3 matrix corresponding to two three-element vectors of Cartesian coordinates. In this case, the antenna rotates around the line joining the two points.

  • "x", "y", or "z" to describe a rotation about the x-, y-, or z-axis, respectively.

For more information, see Rotate Antennas and Arrays.

Example: [0 1 0]

Example: [0 0 0;0 1 0]

Example: "Z"

Data Types: double | string

Object Functions

axialRatioCalculate and plot axial ratio of antenna or array
bandwidthCalculate and plot absolute bandwidth of antenna or array
beamwidthBeamwidth of antenna
chargeCharge distribution on antenna or array surface
currentCurrent distribution on antenna or array surface
designDesign prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiencyCalculate and plot radiation efficiency of antenna or array
EHfieldsElectric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrentCalculate current at feed for antenna or array
impedanceCalculate and plot input impedance of antenna or scan impedance of array
infoDisplay information about antenna, array, or platform
memoryEstimateEstimate memory required to solve antenna or array mesh
meshMesh properties of metal, dielectric antenna, or array structure
meshconfigChange meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwriteWrite antenna or array analysis data to MSI planet file
optimizeOptimize antenna or array using SADEA optimizer
patternPlot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuthAzimuth plane radiation pattern of antenna or array
patternElevationElevation plane radiation pattern of antenna or array
peakRadiationCalculate and mark maximum radiation points of antenna or array on radiation pattern
rcsCalculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequencyCalculate and plot resonant frequency of antenna
returnLossCalculate and plot return loss of antenna or scan return loss of array
showDisplay antenna, array structures, shapes, or platform
sparametersCalculate S-parameters for antenna or array
stlwriteWrite mesh information to STL file
vswrCalculate and plot voltage standing wave ratio (VSWR) of antenna or array element

Examples

collapse all

Open Live Script

Create a reflector backed dipole that has 30 cm length, 25 cm width and spaced 7.5 cm from the dipole for operation at 1 GHz.

d = dipole(Length=0.15,Width=0.015,Tilt=90,TiltAxis=[0 1 0]);
rf = reflector(GroundPlaneLength=30e-2,GroundPlaneWidth=25e-2,...
              Spacing=7.5e-2,Exciter=d);
show(rf)

Figure contains an axes object. The axes object with title reflector antenna element, xlabel x (mm), ylabel y (mm) contains 5 objects of type patch, surface. These objects represent PEC, feed.

Open Live Script

Create a reflector backed dipole antenna using a FR4 dielectric substrate.

d = dielectric("FR4");
di = dipole(Length=0.15,Width=0.015,Tilt=90,TiltAxis='Y');
rf = reflector(GroundPlaneLength=30e-2,GroundPlaneWidth=25e-2,...
               Spacing=7.5e-3,Substrate=d,Exciter=di);
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.

Plot the radiation pattern of the antenna at a frequency of 1 GHz.

figure
pattern(rf,1e9)

Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 6 objects of type patch, surface. This object represents FR4. Hidden axes object 2 contains 18 objects of type surface, line, text, patch. This object represents FR4.

Open Live Script

Create a reflector backed dipole that has infinite length, 25 cm width and spaced 7.5 cm from the dipole for operation at 1 GHz.

d = dipole(Length=0.15,Width=0.015,Tilt=90,TiltAxis=[0 1 0]);
rf = reflector(GroundPlaneLength=inf,GroundPlaneWidth=25e-2,...
              Spacing=7.5e-2,Exciter=d)
rf = 
  reflector with properties:

              Exciter: [1x1 dipole]
            Substrate: [1x1 dielectric]
    GroundPlaneLength: Inf
     GroundPlaneWidth: 0.2500
              Spacing: 0.0750
      EnableProbeFeed: 0
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]


show(rf)

Figure contains an axes object. The axes object with title dipole over infinite ground plane, xlabel x (mm), ylabel y (mm) contains 4 objects of type patch, surface. These objects represent PEC, feed, infinite ground.

Open Live Script

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

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

Open Live Script

Create a rectangular array of the bowtie antennas.

b = bowtieTriangular(Length=0.05)
b = 
  bowtieTriangular with properties:

        Length: 0.0500
    FlareAngle: 90
     Conductor: [1x1 metal]
          Tilt: 0
      TiltAxis: [1 0 0]
          Load: [1x1 lumpedElement]


rectArr = rectangularArray(Element=b,RowSpacing=0.18,ColumnSpacing=0.18)
rectArr = 
  rectangularArray with properties:

           Element: [1x1 bowtieTriangular]
              Size: [2 2]
        RowSpacing: 0.1800
     ColumnSpacing: 0.1800
           Lattice: 'Rectangular'
    AmplitudeTaper: 1
        PhaseShift: 0
              Tilt: 0
          TiltAxis: [1 0 0]

Create a rectangular array with reflector backing structure.

ant = reflector(Exciter=rectArr)
ant = 
  reflector with properties:

              Exciter: [1x1 rectangularArray]
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
              Spacing: 0.0750
      EnableProbeFeed: 0
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]


show(ant)

Figure contains an axes object. The axes object with title reflector antenna element, xlabel x (mm), ylabel y (mm) contains 11 objects of type patch, surface. These objects represent PEC, feed.

Open Live Script

Create a reflector-backed rectangular array of microstrip patch antennas.

p = patchMicrostrip(Substrate=dielectric("FR4"));
ra = rectangularArray(Element=p,RowSpacing=0.075,ColumnSpacing=0.1);
ant = reflector(Exciter=ra,GroundPlaneLength=0.4,GroundPlaneWidth=0.3)
ant = 
  reflector with properties:

              Exciter: [1x1 rectangularArray]
            Substrate: [1x1 dielectric]
    GroundPlaneLength: 0.4000
     GroundPlaneWidth: 0.3000
              Spacing: 0.0750
      EnableProbeFeed: 0
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]


show(ant)

Figure contains an axes object. The axes object with title reflector antenna element, xlabel x (mm), ylabel y (mm) contains 17 objects of type patch, surface. These objects represent PEC, feed, FR4.

References

[1] Balanis, C.A. Antenna Theory. Analysis and Design, 3rd Ed. New York: Wiley, 2005.

Version History

Introduced in R2015a

See Also

| |

Topics