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reflectorSpherical

Create spherical reflector-backed antenna

Description

The reflectorSpherical antenna object creates a spherical reflector-backed antenna. The reflector in the spherical reflector-backed antenna is one-half the size of the sphere. The antenna is used in wide-angle scanning on account of its perfectly symmetrical geometric configuration.

Spherical reflector antenna geometry, default radiation pattern, and impedance plot.

Creation

Description

example

ant = reflectorSpherical creates a spherical reflector-backed antenna. The default antenna object has an exciter as a center-fed dipole located on the X-Y plane. The default antenna object dimensions are chosen for an operating frequency of 1 GHz.

example

ant = reflectorSpherical(Name,Value) sets Properties using name-value pairs. For example, reflectorSpherical('Radius',0.6) sets the spherical reflector radius to 0.6 meters. You can specify multiple name-value pairs. Enclose each property name in quotes. Properties not specified retain their default values.

Properties

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Antenna used as an exciter, specified as an antenna object or an array object.

Example: 'Exciter',dipole

Example: ant.Exciter = dipole('Length',0.1409,'Width',0.02,'FeedOffset',0,'Tilt',90,'TiltAxis',[0 1 0])

Example: ant.Exciter = linearArray('patchMicrostrip')

Radius of the spherical reflector aperture along X and Y-axes, specified as a positive scalar in meters.

Example: 'Radius',0.259

Example: ant.Radius = 0.195

Data Types: double

Signed distance between feed point of the exciter and the origin, specified as a three-element vector with each element unit in meters.

Example: 'FeedOffset',[0 0 0.082]

Example: ant.FeedOffset = [0 0 0.082]

Data Types: double

Perpendicular distance between origin and the aperture of the spherical reflector-backed antenna, specified as a positive scalar in meters.

Example: 'Depth',0.6

Example: ant.Depth = 0.18

Note

Depth should be less than or half the Radius.

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: m = metal('Copper'); 'Conductor',m

Example: m = metal('Copper'); ant.Conductor = m

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: ant.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

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: ant.TiltAxis = 'Z'

Note

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

Data Types: double

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: ant.Load = lumpedElement('Impedance',75)

Object Functions

showDisplay antenna or array structure; display shape as filled patch
impedanceInput impedance of antenna; scan impedance of array
sparametersS-parameter object
returnLossReturn loss of antenna; scan return loss of array
vswrVoltage standing wave ratio of antenna
optimizeOptimize antenna or array using SADEA optimizer
patternRadiation pattern and phase of antenna or array; Embedded pattern of antenna element in array
patternAzimuthAzimuth pattern of antenna or array
patternElevationElevation pattern of antenna or array
axialRatioAxial ratio of antenna
beamwidthBeamwidth of antenna
currentCurrent distribution on metal or dielectric antenna or array surface
chargeCharge distribution on metal or dielectric antenna or array surface
efficiencyRadiation efficiency of antenna
EHfieldsElectric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
meshMesh properties of metal or dielectric antenna or array structure
designDesign prototype antenna or arrays for resonance at specified frequency
rcsCalculate and plot radar cross section (RCS) of platform, antenna, or array

Examples

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Create a spherical reflector-backed antenna object with default properties.

ant = reflectorSpherical
ant = 
  reflectorSpherical with properties:

       Exciter: [1x1 dipole]
        Radius: 0.1500
         Depth: 0.1500
    FeedOffset: [0 0 0.0750]
          Tilt: 0
      TiltAxis: [1 0 0]
          Load: [1x1 lumpedElement]

View the antenna.

show(ant)

Figure contains an axes. The axes with title reflectorSpherical antenna element contains 5 objects of type patch, surface. These objects represent PEC, feed.

Create a spherical reflector-backed antenna with a dipole as an exciter spaced at 90 millimeters.

rs = reflectorSpherical;
rs.FeedOffset(3) = 90e-3;

Visualize the antenna.

figure
show(rs)

Figure contains an axes. The axes with title reflectorSpherical antenna element contains 5 objects of type patch, surface. These objects represent PEC, feed.

Plot the S-parameters at 1 GHz.

s = sparameters(rs,(9:0.1:11)*1e9);
figure
rfplot(s)

Figure contains an axes. The axes contains an object of type line. This object represents dB(S_{11}).

Create a waveguide designed at 10 GHz backed with a spherical reflector.

w = design(waveguide,10e9);
rs = reflectorSpherical('Exciter',w);
rs.Exciter.Tilt = 90;
rs.Exciter.TiltAxis = [ 0 1 0];

Visualize the antenna.

figure
show(rs)

Figure contains an axes. The axes with title reflectorSpherical antenna element contains 5 objects of type patch, surface. These objects represent PEC, feed.

Plot the radiation pattern at 10 GHz.

figure
pattern(rs,10e9)

Figure contains an axes and other objects of type uicontrol. The axes contains 5 objects of type patch, surface.

Create a circular array with discone antennas.

d = discone('Height',0.04);
circArr = circularArray('Element',d,'Radius',0.1);

Create a spherical reflector antenna with circular array exciter.

ant = reflectorSpherical('Exciter',circArr,'Radius',0.25)
ant = 
  reflectorSpherical with properties:

       Exciter: [1x1 circularArray]
        Radius: 0.2500
         Depth: 0.1500
    FeedOffset: [0 0 0.0750]
          Tilt: 0
      TiltAxis: [1 0 0]
          Load: [1x1 lumpedElement]

show(ant)

Figure contains an axes. The axes with title reflectorSpherical antenna element contains 15 objects of type patch, surface. These objects represent PEC, feed.

References

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

Introduced in R2020b