customDualReflectors

Create custom dual-reflector antenna

Since R2022a

Description

The default customDualReflectors object creates a dual-reflector antenna with empty geometries for the main and sub reflectors and the hornConical element as the 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.

Creation

Syntax

cdr = customDualReflectors

cdr = customDualReflectors(PropertyName=Value)

Description

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.

cdr = customDualReflectors(PropertyName=Value) sets properties using one or more name–value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify, retain their default values.

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

Exciter — Antenna or array to use as exciter

hornConical (default) | antenna object | array object | custom antenna object | empty array

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

• 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: []

MainReflector — Cartesian coordinates of points that define main reflector surface

empty (default) | N-by-3 matrix | triangulation object

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: MainReflector=triangulation(T,P)

Data Types: double

SubReflector — Cartesian coordinates of points that define sub reflector surface

empty (default) | N-by-3 matrix | triangulation object

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: SubReflector=triangulation(T,P)

Data Types: double

ReflectorOffset — Cartesian coordinates of main and sub reflector offsets

[0 0 0; 0 0 0.2294] (default) | two three-element vectors

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: [-0.1 0 0; 0.03 0 0.224]

Data Types: double

FeedOffset — Cartesian coordinates to offset exciter feed point

[0.0064 0 0.1173] (default) | three-element vector

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: [0.0850 0 0]

Data Types: double

ReflectorTilt — Tilt angle of reflectors

[0 0] (default) | two-element vector

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: [40 200]

Data Types: double

RemeshReflectors — Flag to re-mesh reflectors

1 (default) | 0 | true | false

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: 0

Data Types: logical | string

Tilt — Tilt angle of antenna

0 (default) | scalar | vector

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

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector | 2-by-3 matrix | "X" | "Y" | "Z"

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

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.

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

axialRatio	Calculate and plot axial ratio of antenna or array
bandwidth	Calculate and plot absolute bandwidth of antenna or array
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
current	Current distribution on antenna or array surface
efficiency	Calculate and plot radiation efficiency of antenna or array
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrent	Calculate current at feed for antenna or array
impedance	Calculate and plot input impedance of antenna or scan impedance of array
info	Display information about antenna, array, or platform
memoryEstimate	Estimate memory required to solve antenna or array mesh
mesh	Generate and view mesh for antennas, arrays, and custom shapes
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwrite	Write antenna or array analysis data to MSI planet file
optimize	Optimize antenna and array catalog elements using SADEA or TR-SADEA algorithm
pattern	Plot radiation pattern of antenna, array, or embedded element of array
patternAzimuth	Azimuth plane radiation pattern of antenna or array
patternElevation	Elevation plane radiation pattern of antenna or array
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and plot resonant frequency of antenna
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
sparameters	Calculate S-parameters for antenna or array
stlwrite	Write mesh information to STL file
vswr	Calculate and plot voltage standing wave ratio (VSWR) of antenna or array element

Examples

Build Custom Dual-Reflector Antenna

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: [1×1 hornConical]
       MainReflector: [3364×3 double]
        SubReflector: [144×3 double]
     ReflectorOffset: [2×3 double]
          FeedOffset: [0.0064 0 0.1173]
       ReflectorTilt: [0 0]
    RemeshReflectors: 1
                Tilt: 0
            TiltAxis: [1 0 0]
                Load: [1×1 lumpedElement]
          SolverType: 'MoM-PO'

View the antenna.

show(cdr)

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

pattern(cdr,18.51e9) 

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

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

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)

Version History

Introduced in R2022a