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.

Creation

Syntax

ant = reflectorCylindrical

ant = reflectorCylindrical(Name,Value)

Description

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.

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

Exciter — Antenna or array used as exciter

dipole (default) | antenna object | array object

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')

GroundPlaneLength — Reflector length

0.2 (default) | positive scalar

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

Example: 'GroundPlaneLength',0.6

Example: ant.GroundPlaneLength = 0.18

Data Types: double

GroundPlaneWidth — Reflector width

0.2 (default) | positive scalar

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

Example: 'GroundPlaneWidth',0.4

Example: ant.GroundPlaneWidth = 0.18

Data Types: double

Spacing — Distance between reflector and exciter

0.075 (default) | scalar

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

Example: 'Spacing',0.059

Example: ant.Spacing = 0.195

Data Types: double

Depth — Perpendicular distance between ground plane and reflector aperture

0.075 (default) | positive scalar

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

Enable Probe Feed — Flag to enable probe feed

0 (default) | 1

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

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

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

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'

Note

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

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: ant.Load = 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
optimize	Optimize antenna or array using SADEA optimizer
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
design	Design prototype antenna or arrays for resonance around specified frequency
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array

Examples

Design Cylindrical Reflector with Default Properties

Create a cylindrical reflector antenna object with default properties.

ant = reflectorCylindrical;

View the antenna object.

show(ant)

Use Rounded Bow-Tie Dipole Antenna as Exciter

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)

Plot the radiation pattern at 1.5 GHz.

figure
pattern(r,1.5e9)

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)

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

figure
pattern(re,1.5e9)

Create Linear Array of Crossed Dipole Backed With Cylindrical Reflector

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)

Create Minkowski's Loop Fractal Antenna with Cylindrical Reflector Backing Structure

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)

References

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

Version History

Introduced in R2020b