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gregorian

Create Gregorian antenna

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Description

The default gregorian object creates a conical horn fed Gregorian antenna resonating around 18.2 GHz. A Gregorian antenna is a parabolic antenna. In this antenna, the feed antenna is mounted at or behind the surface of the main parabolic reflector and aimed at the sub-reflector. This antenna is used in radio telescopes and communication satellites. For more information see, Architecture of Gregorian Antenna.

Creation

Syntax

ant = gregorian
ant = gregorian(Name=Value)

Description

ant = gregorian creates a horn conical fed Gregorian antenna with default property values. The default dimensions are chosen for an operating frequency of around 18.2 GHz. This antenna gives maximum gain when operated at 18.3 GHz.

example

ant = gregorian(Name=Value) sets properties using 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 that you do not specify, retain their default values.

For example, ant = gregorian(FocalLength=[0.4 0.22]) creates a Gregorian antenna with the main reflector of focal length 0.4 m and the sub-reflector of focal length 0.22 m.

Properties

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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

  • Measured pattern data of an antenna or array: measuredAntenna

  • Empty array

To create the reflector backing structure without an exciter, specify this property as an empty array.

Example: dipole

Example: linearArray(Element=patchMicrostrip)

Example: customAntenna

Example: measuredAntenna

Example: []

Radius of the main and sub-reflector, specified as a two-element vector with each element unit in meters. The first element specifies the radius of the main reflector, and the second element specifies the radius of the sub-reflector.

Example: Radius=[0.4 0.2]

Data Types: double

Focal length of the main and sub-reflector, specified as a two-element vector with each element unit in meters. The first element specifies the focal length of the main reflector, and the second element specifies the focal length of the subreflector.

Example: FocalLength=[0.35 0.2]

Data Types: double

Lumped elements added to the antenna feed, specified as a lumped element 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=lumpedelement. lumpedelement is the object for the load created using lumpedElement.

Example: lumpedElement(Impedance=75)

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

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

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

axialRatioCalculate and plot axial ratio of antenna or array
bandwidthCalculate and plot absolute bandwidth of antenna or array
beamwidthBeamwidth of antenna
chargeCharge distribution on antenna or array surface
currentCurrent distribution on antenna or array surface
designDesign prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiencyCalculate and plot radiation efficiency of antenna or array
EHfieldsElectric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrentCalculate current at feed for antenna or array
impedanceCalculate and plot input impedance of antenna or scan impedance of array
infoDisplay information about antenna, array, or platform
memoryEstimateEstimate memory required to solve antenna or array mesh
meshMesh properties of metal, dielectric antenna, or array structure
meshconfigChange meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwriteWrite antenna or array analysis data to MSI planet file
optimizeOptimize antenna or array using SADEA optimizer
patternPlot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuthAzimuth plane radiation pattern of antenna or array
patternElevationElevation plane radiation pattern of antenna or array
peakRadiationCalculate and mark maximum radiation points of antenna or array on radiation pattern
rcsCalculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequencyCalculate and plot resonant frequency of antenna
returnLossCalculate and plot return loss of antenna or scan return loss of array
showDisplay antenna, array structures, shapes, or platform
solverAccess FMM solver settings for electromagnetic analysis
sparametersCalculate S-parameters for antenna or array
stlwriteWrite mesh information to STL file
vswrCalculate and plot voltage standing wave ratio (VSWR) of antenna or array element

Examples

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Open Live Script

Create and view a default Gregorian antenna.

ant = gregorian
ant = 
  gregorian with properties:

        Exciter: [1x1 hornConical]
         Radius: [0.3175 0.0330]
    FocalLength: [0.2536 0.1416]
           Tilt: 0
       TiltAxis: [1 0 0]
           Load: [1x1 lumpedElement]
     SolverType: 'MoM-PO'


show(ant)

Figure contains an axes object. The axes object with title gregorian antenna element, xlabel x (mm), ylabel y (mm) contains 7 objects of type patch, surface. These objects represent PEC, feed.

Plot the radiation pattern of the antenna at 18.48 GHz.

pattern(ant,18.48e9)

Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 7 objects of type patch, surface. Hidden axes object 2 contains 19 objects of type surface, line, text, patch.

Open Live Script

Create an array of vee dipole antennas.

e = dipoleVee(ArmLength=[0.03 0.03],Width=0.01);
arr = rectangularArray(Element=e,RowSpacing=0.05,ColumnSpacing=0.05);

Create a Gregorian antenna with rectangular array as exciter

ant = gregorian(Exciter=arr);
show(ant)

Figure contains an axes object. The axes object with title gregorian antenna element, xlabel x (mm), ylabel y (mm) contains 13 objects of type patch, surface. These objects represent PEC, feed.

More About

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Version History

Introduced in R2019b

See Also

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