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.

Creation

Syntax

cdr = customDualReflectors

cdr = customDualReflectors(Name,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(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

Exciter — Antenna or array to use as exciter

hornConical (default) | antenna object | array object

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)

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: cdr.MainReflector=preflector

Example: cdr=customDualReflectors('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: cdr.SubReflector=psubreflector

Example: cdr=customDualReflectors('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: '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

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: 'FeedOffset',[0.0850 0 0]

Example: cdr.FeedOffset = [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: 'ReflectorTilt',[40 200]

Example: cdr.ReflectorTilt=[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: 'RemeshReflectors',0

Example: cdr.RemeshReflectors=0

Data Types: logical | string

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: 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

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: ant.TiltAxis = 'Z'

Load — Lumped elements

[1x1 lumpedElement] (default) | lumpedElement object

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)

SolverType — Solver for antenna analysis

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

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

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
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
optimize	Optimize antenna or array using SADEA optimizer
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
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
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array

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: [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)

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