reflectorGrid

Create grid reflector-backed antenna

Since R2020b

Description

The reflectorGrid object creates a grid reflector-backed antenna. The grid reflector uses a grid of parallel wires or bars oriented in one direction. Grid reflectors can be used as high-gain antennas in point-to-point communications.

Creation

Syntax

ant = reflectorGrid

ant = reflectorGrid(Name=Value)

Description

ant = reflectorGrid creates a grid reflector-backed antenna. The default antenna object has an exciter as a dipole with the feed point located at the origin on the X-Y plane, and the antenna dimensions are chosen for an operating frequency of 1 GHz.

ant = reflectorGrid(Name=Value) creates a grid reflector antenna, with additional Properties specified by 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 not specified retain their default values.

For example, reflectorGrid(GroundPlaneWidth=0.6) creates a grid reflector with a width of 0.6 meters. You can specify multiple name-value pairs.

Properties

Exciter — Antenna or array type used as exciter

dipole (default) | antenna object | array object | empty array

Exciter antenna or array type, specified as a single-element antenna object, an array object, or an empty array. Except for reflector and cavity antenna elements, you can use any Antenna Toolbox™ antenna or array element as an exciter. To create the cavity backing structure without the exciter, specify this property as an empty array.

Example: horn

Example: linearArray(Element=patchMicrostrip)

Example: []

Spacing — Distance between reflector and exciter

0.175 (default) | positive scalar

Distance between reflector and exciter, specified as a positive scalar in meters.

Example: 0.259

Data Types: double

GroundPlaneLength — Reflector length

0.2 (default) | positive scalar

Reflector length along the X-axis, specified as a positive scalar in meters.

Example: 0.6

Data Types: double

GroundPlaneWidth — Reflector width

0.2 (default) | positive scalar

Reflector width along the Y-axis, specified as a positive scalar in meters.

Example: 0.6

Data Types: double

GridType — Type of grid used in reflector

"HV" (default) | "VH" | "V" | "H"

Type of the grid used in the reflector, specified as either one of the following:

• "H" — grids are arranged horizontally in the reflector.

• "V" — grids are arranged vertically in the reflector.

• "HV" or "VH" — grids are arranged both horizontally and vertically in the reflector.

Example: "H"

Data Types: char

GridSpacing — Distance between two grid cells

0.018 (default) | positive scalar

Distance between the two grid cells, specified as a positive scalar in meters.

Example: 0.018

Data Types: double

GridWidth — Width of each grid cell

0.022 (default) | positive scalar

Width of each grid cell, specified as a positive scalar in meters.

Example: 0.3

Data Types: double

Conductor — Type of metal material

"PEC" (default) | metal object

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")

Tilt — Tilt angle of antenna

0 (default) | scalar | vector

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

Example: Tilt=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.

Note

The wireStack antenna object only accepts the dot method to change its properties.

Data Types: double

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector of Cartesian coordinates | two three-element vectors of Cartesian coordinates | 'X' | 'Y' | 'Z'

Tilt axis of the antenna, specified as:

• 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, each specified as three-element vectors of Cartesian coordinates. In this case, the antenna rotates around the line joining the two points in space.

• A string input describing simple rotations around one of the principal axes, 'X', 'Y', or 'Z'.

For more information, see Rotate Antennas and Arrays.

Example: TiltAxis=[0 1 0]

Example: TiltAxis=[0 0 0;0 1 0]

Example: TiltAxis = 'Z'

Data Types: double

Load — Lumped elements

[1x1 lumpedElement] (default) | lumpedElement object

Lumped elements added to the antenna feed, specified as a lumpedElement object. You can add a load anywhere on the surface of the antenna. By default, the load is at the feed. For more information, see lumpedElement.

Example: Load=lumpedelements, where lumpedelements is the load added to the antenna feed.

Example: lumpedElement(Impedance=75)

Object Functions

show	Display antenna, array structures or shapes
impedance	Input impedance of antenna; scan impedance of array
sparameters	Calculate S-parameter for antenna and antenna array objects
returnLoss	Return loss of antenna; scan return loss of array
vswr	Voltage standing wave ratio of antenna
pattern	Radiation pattern and phase of antenna or array; Embedded pattern of antenna element in array
patternAzimuth	Azimuth pattern of antenna or array
patternElevation	Elevation pattern of antenna or array
axialRatio	Axial ratio of antenna
beamwidth	Beamwidth of antenna
current	Current distribution on antenna or array surface
charge	Charge distribution on antenna or array surface
efficiency	Radiation efficiency of antenna
EHfields	Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
mesh	Mesh properties of metal, dielectric antenna, or array structure
optimize	Optimize antenna or array using SADEA optimizer
design	Design prototype antenna or arrays for resonance around specified frequency
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array
numGridsToSpacing	Calculate grid spacing in grid for reflectorGrid object

Examples

Design Grid Reflector-Backed Antenna with Default Properties

Create and view a grid reflector-backed antenna object with default properties.

ant = reflectorGrid;
show(ant)

Plot the radiation pattern of the antenna at 1 GHz.

pattern(ant,1e9)

Design Grid Reflector-Backed Biquad Antenna

Create and view a grid reflector-backed biquad antenna with an arm length of 0.01 meters.

b = biquad(ArmLength=0.01);
h = reflectorGrid(Exciter=b);
show(h)

Plot the radiation pattern of the antenna at 0.6 GHz.

pattern(h,0.6e9)

Change Grid Type in Grid Reflector-Backed Antenna

Create and view grid reflector-baked dipole blade antenna.

d = dipoleBlade(Length=0.1,TaperLength=0.05,FeedGap=0.002);
h = reflectorGrid(Exciter=d);
show(h)

Change the grid type from "HV" to "H".

h.GridType = "H";

View the antenna with grid type "H".

show(h)

Plot the radiation pattern at 1 GHz.

pattern(h,1e9)

Create Grid Reflector-Backed Rectangular Array

Create a rectangular array of cylindrical dipole antennas.

d = dipoleCylindrical(Length=0.2,Radius=0.005);
arr = rectangularArray(Element=d,Size=[4 4],RowSpacing=0.029,ColumnSpacing=0.029);

Create a grid reflector-backed rectangular array.

ant = reflectorGrid(Exciter=arr,Spacing=0.2)

ant = 
  reflectorGrid with properties:

              Exciter: [1x1 rectangularArray]
              Spacing: 0.2000
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
             GridType: 'HV'
          GridSpacing: 0.0180
            GridWidth: 0.0220
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(ant)

Create Antipodal Vivaldi Antenna with Grid Reflector Backing Structure

Create and visualize a grid reflector-backed antipodal Vivaldi antenna.

ant = reflectorGrid(Exciter=vivaldiAntipodal)

ant = 
  reflectorGrid with properties:

              Exciter: [1x1 vivaldiAntipodal]
              Spacing: 0.1750
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
             GridType: 'HV'
          GridSpacing: 0.0180
            GridWidth: 0.0220
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(ant)

Analyze Planar Reflector Grid Structure using Planewave Excitation

This example shows how to create and analyze a planar reflector grid structure without any exciter element, using planeWaveExcitation.

Create default reflector grid antenna

Create a reflector grid antenna operating at 1 GHz using the design function and the reflectorGrid element from the antenna catalog, and view it.

f=1e9;
ant=design(reflectorGrid,f);
figure;
show(ant)

Derive backing structure

Derive the backing structure from this reflector grid antenna by assigning empty value to the 'Exciter' property and view it.

ant.Exciter=[]

ant = 
  reflectorGrid with properties:

              Exciter: []
              Spacing: 0.1749
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
             GridType: 'HV'
          GridSpacing: 0.0180
            GridWidth: 0.0220
            Conductor: [1x1 metal]
                 Tilt: 0
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

figure;
show(ant)

Mesh reflector grid

Mesh the grid structure with a maximum edge length of 10 mm.

figure;
mesh(ant,MaxEdgeLength=10e-3)

Plot surface current distribution

Use planewave excitation to excite the grid structure and plot the surface current distribution at 1 GHz.

pw=planeWaveExcitation(Element=ant,Direction=[0 0 -1],Polarization=[1 0 0])

pw = 
  planeWaveExcitation with properties:

         Element: [1x1 reflectorGrid]
       Direction: [0 0 -1]
    Polarization: [1 0 0]
      SolverType: 'MoM'

figure;
current(pw,f,Scale="log10")

References

[1] Balanis, Constantine A. Antenna Theory: Analysis and Design. 3rd ed. Hoboken, NJ: John Wiley, 2005.

Version History

Introduced in R2020b