reflectorGrid

Create grid reflector-backed antenna

Description

The default reflectorGrid object creates a grid reflector-backed antenna resonating around 1 GHz. 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(PropertyName=Value)

Description

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

ant = reflectorGrid(PropertyName=Value) sets properties using one or more name–value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify, 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 | custom antenna object | empty array

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: []

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

metal("PEC") (default) | metal object

Type of the metal used as a conductor, specified as a metal object. You can choose any metal from the MetalCatalog or specify a metal of your choice. 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 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

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector | 2-by-3 matrix | "X" | "Y" | "Z"

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

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.

Example: lumpedElement(Impedance=75)

Object Functions

axialRatio	Calculate and plot axial ratio of antenna or array
bandwidth	Calculate and plot absolute bandwidth of antenna or array
beamwidth	Beamwidth of antenna
current	Current distribution on antenna or array surface
charge	Charge distribution on antenna or array surface
design	Create antenna, array, or AI-based antenna resonating at specified frequency
efficiency	Calculate and plot radiation efficiency of antenna or array
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrent	Calculate current at feed for antenna or array
impedance	Calculate and plot input impedance of antenna or scan impedance of array
info	Display information about antenna, array, or platform
memoryEstimate	Estimate memory required to solve antenna or array mesh
mesh	Generate and view mesh for antennas, arrays, and custom shapes
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwrite	Write antenna or array analysis data to MSI planet file
numGridsToSpacing	Calculate grid spacing in for reflectorGrid object
optimize	Optimize antenna and array catalog elements using SADEA or TR-SADEA algorithm
pattern	Plot radiation pattern of antenna, array, or embedded element of array
patternAzimuth	Azimuth plane radiation pattern of antenna or array
patternElevation	Elevation plane radiation pattern of antenna or array
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and plot resonant frequency of antenna
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
sparameters	Calculate S-parameters for antenna or array
stlwrite	Write mesh information to STL file
vswr	Calculate and plot voltage standing wave ratio (VSWR) of antenna or array element

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