reflectorSpherical

Create spherical reflector-backed antenna

Since R2020b

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.

Creation

Syntax

ant = reflectorSpherical

ant = reflectorSpherical(Name=Value)

Description

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.

ant = reflectorSpherical(Name=Value) creates a cavity-backed 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, reflectorSpherical(Radius=0.6) sets the spherical reflector radius to 0.6 meters.

Properties

Exciter — Antenna or array used as exciter

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

Exciter antenna or array type, specified as an antenna object, an array object, measured pattern data of an antenna, 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 reflector backing structure without the exciter, specify this property as an empty array.

Example: dipole

Example: linearArray(Element=patchMicrostrip)

Example: measuredAntenna

Example: []

Radius — Radius of spherical aperture

0.15 (default) | positive scalar

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

Example: 0.259

Data Types: double

FeedOffset — Signed distance between feed point and origin

[0 0 0.075] (default) | three-element vector

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

Example: [0 0 0.082]

Data Types: double

Depth — Perpendicular distance between origin and aperture of antenna

0.15 (default) | positive scalar

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

Example: 0.6

Note

Depth should be less than or half the Radius.

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)

SolverType — Solver for antenna analysis

"MoM-PO" (default) | "MoM" | "PO" | "FMM"

Solver for antenna analysis, specified as a string. Default solver is "MoM-PO"(Method of Moments-Physical Optics hybrid). Other supported solvers are: "MoM" (Method of Moments), "PO" (Physical optics) or "FMM" (Fast Multipole Method).

Example: SolverType="MoM"

Data Types: string

Object Functions

show	Display antenna, array structures or shapes
solver	Access FMM solver for electromagnetic analysis
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 Spherical Reflector-Backed Antenna with Default Properties

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]
    SolverType: 'MoM-PO'

View the antenna.

show(ant)

Plot S-Parameter of Spherical Reflector-Backed Dipole Antenna

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)

Plot the S-parameters at 1 GHz.

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

Plot Radiation Pattern of Spherical Reflector-Backed Waveguide Antenna

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)

Plot the radiation pattern at 10 GHz.

figure
pattern(rs,10e9)

Create Spherical Reflector Antenna with Circular Array of Discone Antennas

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]
    SolverType: 'MoM-PO'

show(ant)

References

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

Version History

Introduced in R2020b