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reflectorCylindrical

Create cylindrical reflector-backed antenna

Description

The reflectorCylindrical antenna object creates a cylindrical reflector-backed antenna. The cylindrical shape of the reflector allows you to focus the signal to the antenna surface. Cylindrical reflectors are widely used as high-gain apertures fed with line sources and in airborne navigational antennas where sharp azimuthal beams and wide-angle vertical coverage is required.

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

Creation

Description

example

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

example

ant = reflectorCylindrical(Name,Value) sets Properties using name-value pairs. For example, reflectorCylindrical('GroundPlaneWidth',0.21) creates a cylindrical reflector with a width of 0.21 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 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')

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

Example: 'GroundPlaneLength',0.6

Example: ant.GroundPlaneLength = 0.18

Data Types: double

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

Example: 'GroundPlaneWidth',0.4

Example: ant.GroundPlaneWidth = 0.18

Data Types: double

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

Example: 'Spacing',0.059

Example: ant.Spacing = 0.195

Data Types: double

Perpendicular distance between the ground plane and the aperture of the cylindrical reflector, specified as a positive scalar in meters.

Example: 'Depth',0.09

Example: ant.Depth = 0.049

Note

Depth should be less than or equal to half of the GroundPlaneLength.

Data Types: double

Flag to enable the probe feed, specified as 0 or 1 . Setting the flag to 0 disables the probe feed, and setting the flag to 1 enables it.

Example: 'EnableProbeFeed',1

Example: ant.EnableProbeFeed = 1

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
sparametersCalculate S-parameter for antenna and antenna array objects
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 around specified frequency
rcsCalculate and plot radar cross section (RCS) of platform, antenna, or array

Examples

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Create a cylindrical reflector antenna object with default properties.

ant = reflectorCylindrical;

View the antenna object.

show(ant)

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

Create a reflectorCylindrical antenna object with a rounded bow-tie dipole antenna as an exciter.

b = bowtieRounded('Length',96e-3,'Tilt',90,'TiltAxis',[0 1 0]);
r = reflectorCylindrical('Exciter',b,'Spacing',100e-3);
    

View the antenna object.

figure
show(r)

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

Plot the radiation pattern at 1.5 GHz.

figure
pattern(r,1.5e9)

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

Enable the probe feed for the reflectorCylindrical antenna object.

re = reflectorCylindrical('Exciter',b,'Spacing',100e-3,'EnableProbeFeed',1);

View the antenna object with the probe feed enabled.

figure
show(re)

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

Plot the radiation pattern of the antenna object at 1.5 GHz with the probe feed enabled.

figure
pattern(re,1.5e9)

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

Create a linear array of crossed dipole antenna.

d = dipoleCrossed('Tilt',90,'TiltAxis',[0 1 0]);
la = linearArray('Element',d,'NumElements',4,'ElementSpacing',0.05,'Tilt',90,'TiltAxis',[0 0 1]);

Create a cylindrical reflector backed array.

ant = reflectorCylindrical('Exciter',la,'Tilt',90)
ant = 
  reflectorCylindrical with properties:

              Exciter: [1x1 linearArray]
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
              Spacing: 0.0750
                Depth: 0.0750
      EnableProbeFeed: 0
            Conductor: [1x1 metal]
                 Tilt: 90
             TiltAxis: [1 0 0]
                 Load: [1x1 lumpedElement]

show(ant)

Figure contains an axes object. The axes object with title reflectorCylindrical antenna element contains 19 objects of type patch, surface. These objects represent PEC, feed.

Create a cylindrical reflector-backed Minkowski's loop fractal antenna.

e = fractalIsland('Substrate',dielectric('Teflon'),'Tilt',90,'TiltAxis',[0 0 1]);
ant = reflectorCylindrical('Exciter',e)
ant = 
  reflectorCylindrical with properties:

              Exciter: [1x1 fractalIsland]
    GroundPlaneLength: 0.2000
     GroundPlaneWidth: 0.2000
              Spacing: 0.0750
                Depth: 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 reflectorCylindrical antenna element contains 7 objects of type patch, surface. These objects represent PEC, feed, Teflon.

References

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

Introduced in R2020b