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customDualReflectors

Create custom dual-reflector antenna

Description

The customDualReflectors object creates a dual-reflector antenna with empty geometries for the main and sub reflectors and the hornConical element as the default exciter. Once you create the object, you have to specify the geometry coordinates of the main and sub reflector surfaces in N-by-3 matrices and assign them to the MainReflector and SubReflector properties of the object before using the show function to view the antenna. N represents the total number of points to use for defining the geometry. Value of N can be different for the main and the sub reflector. Alternatively, you can also use a triangulation object to define the reflector geometry. You can also change the orientation of the reflectors and the exciter. You can use either a single antenna element or an array as the exciter for the object. Further, you can also create an antenna array using customDualReflectors object as its element. Dual-reflector antennas have very high gain and low spillover and are used in satellite communications.

Dual reflector antenna geometry

Creation

Description

example

cdr = customDualReflectors creates a dual-reflector antenna with empty main and sub reflector geometries and conical horn antenna as the default exciter. After creating the object, specify the coordinates of the reflector surfaces in a N-by-3 matrix or import the coordinates from a MAT file.

example

cdr = customDualReflectors(Name,Value) sets Properties using one or more name-value pairs. For example, cdr = customDualReflectors('FeedOffset',[0.0850 0 0]) relocates the feed to the point (0.0850, 0, 0) with respect to the origin.

Properties

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Antenna or array to use as an exciter, specified as an antenna or an array object.

Example: cdr = customDualReflectors('Exciter',dipole)

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

Example: cdr.Exciter = linearArray('Element',patchMicrostrip)

Cartesian coordinates of the main reflector surface, specified as an N-by-3 matrix with each element unit in meters. N represents the total number of points that define the main reflector surface. You can also import the coordinates from a MAT file. This property also accepts triangulation method for defining the main reflector surface.

Example: 'MainReflector',preflector

Example: cdr.MainReflector=preflector

Example: cdr=customDualReflectors('MainReflector',triangulation(T,P))

Data Types: double

Cartesian coordinates of the sub reflector surface, specified as an N-by-3 matrix with each element unit in meters. N represents the total number of points that define the sub reflector surface. You can also import the coordinates from a MAT file. This property also accepts triangulation method for defining the sub reflector surface.

Example: 'SubReflector',psubreflector

Example: cdr.SubReflector=psubreflector

Example: cdr=customDualReflectors('SubReflector',triangulation(T,P))

Data Types: double

Cartesian coordinates of the main and sub reflector offsets with respect to the origin, specified as a 2-by-3 matrix with each element unit in meters. The first row corresponds to the main reflector offset and the second row corresponds to the sub reflector offset.

Example: 'ReflectorOffset',[-0.1 0 0;0.03 0 0.224]

Example: cdr.ReflectorOffset=[-0.1 0 0;0.03 0 0.224]

Data Types: double

Cartesian coordinates to offset the exciter feed point, specified as a three-element vector with each element unit in meters. If you have specified an array of exciters in the Exciter property, use this property to offset the center of the array.

Example: 'FeedOffset',[0.0850 0 0]

Example: cdr.FeedOffset = [0.0850 0 0]

Data Types: double

Tilt angle of the reflectors, specified as a two-element vector with each element unit in degrees. The first element specifies the tilt of the main reflector, and the second element specifies the tilt of the sub reflector. Specify values in the range [–360, 360].

Example: 'ReflectorTilt',[40 200]

Example: cdr.ReflectorTilt=[40 200]

Data Types: double

Flag to re-mesh the reflectors, specified as a numeric or logical 1(true) or 0(false). Set this property to true to re-mesh the reflectors.

Example: 'RemeshReflectors',0

Example: cdr.RemeshReflectors=0

Data Types: logical | string

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: cdr.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.

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'

Lumped elements added to the antenna feed, specified as a lumpedElement object handle. 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, where lumpedElement is load added to the antenna feed.

Example: cdr.Load = lumpedElement('Impedance',75)

Solver for antenna analysis, specified as the comma-separated pair consisting of 'SolverType' and 'MoM-PO', 'PO' (Physical Optics), 'MoM' (Method of Moments), or 'FMM' (Fast Multipole Method).

Example: 'SolverType','MOM'

Data Types: char

Object Functions

showDisplay antenna, array structures or shapes
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
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
optimizeOptimize antenna or array using SADEA optimizer
axialRatioAxial ratio of antenna
beamwidthBeamwidth of antenna
currentCurrent distribution on antenna or array surface
chargeCharge distribution on antenna or array surface
EHfieldsElectric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
meshMesh properties of metal, dielectric antenna, or array structure
rcsCalculate and plot radar cross section (RCS) of platform, antenna, or array

Examples

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Load the MAT files containing the variables which store the coordinates for the main and sub reflector surfaces.

load mainref.mat; %Loads a variable 'preflector' into the workspace
load subref.mat; %Loads a variable 'psubreflector' into the workspace

Create a customDualReflectors object by assigning the coordinates to the MainReflector and SubReflector properties.

cdr = customDualReflectors('MainReflector',preflector,'SubReflector',psubreflector)
cdr = 
  customDualReflectors with properties:

             Exciter: [1x1 hornConical]
       MainReflector: [3364x3 double]
        SubReflector: [144x3 double]
     ReflectorOffset: [2x3 double]
          FeedOffset: [0.0064 0 0.1173]
       ReflectorTilt: [0 0]
    RemeshReflectors: 1
                Tilt: 0
            TiltAxis: [1 0 0]
                Load: [1x1 lumpedElement]
          SolverType: 'MoM-PO'

View the antenna.

show(cdr)

Figure contains an axes object. The axes object with title customDualReflectors antenna element contains 7 objects of type patch, surface. These objects represent PEC, feed.

Plot a 3-D radiation pattern of this antenna at 18.51 GHz.

pattern(cdr,18.51e9) 

{"String":"Figure contains an axes object and other objects of type uicontrol. The axes object contains 7 objects of type patch, surface.","Tex":[],"LaTex":[]}

Plot the elevation pattern of this antenna in the X-Z plane.

pattern(cdr,18.51e9,0,1:1:360)

{"String":"Figure contains an object of type uicontainer.","Tex":[],"LaTex":[]}

Tilt and offset the reflectors and the feed. View the transformed antenna.

cdr.ReflectorTilt=[40 200];
cdr.ReflectorOffset=[-0.1 0  0;0.03 0 0.224];
cdr.FeedOffset=[0.0072 0 0.02];
show(cdr)

{"String":"Figure contains an axes object. The axes object with title customDualReflectors antenna element contains 7 objects of type patch, surface. These objects represent PEC, feed.","Tex":"customDualReflectors antenna element","LaTex":[]}

Version History

Introduced in R2022a