customAntenna

Create custom antenna from geometric shapes

Since R2023b

Description

The customAntenna object lets you create an antenna from a custom shape. You can use the basic 2-D and 3-D shapes from the catalog and perform geometric operations on them to create a custom shape. You can also use the triangulation or shape vertices to create custom shapes. You assign a feed to a location on the shape to convert it into an antenna. Perform port, surface, and field analysis on this antenna. You can use this antenna as an exciter for the cavity and reflector type backing structures, element in the arrays, element for the installed antenna analysis, or element in the plane wave excitation environment.

Creation

Syntax

c = customAntenna

c = customAntenna(Name=Value)

Description

c = customAntenna

creates a custom antenna object.

c = customAntenna(Name=Value) sets additional 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 not specified retain their default values.

Properties

Shape — Antenna shape

"[]" (default) | shape object

Antenna shape, specified as a shape object from these:

• 2-D Shapes: shape.Rectangle, shape.Circle, shape.Ellipse, or shape.Polygon

• 3-D Shapes: shape.Box, shape.OpenBox, shape.Cylinder, shape.OpenCylinder, shape.Sphere, shape.Custom3D

Example: shape.Circle

Example: shape.Sphere

FeedLocation — Location of antenna feed

"[]" (default) | two-element real vector | three-element real vector

Location of the antenna feed created using the createFeed function, returned as either a two-element real vector for 2-D shapes or a three-element real vector for 3-D shapes. Feed location follows the Cartesian coordinate system.

Example: [1.2 0.25]

Example: [-0.0908 -0.1250 0.9755]

Data Types: double

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. For more information, see lumpedElement.

Example: lumpedElement(Impedance=75)

Object Functions

axialRatio	Calculate and/or plot axial ratio of antenna or array
bandwidth	Calculate and/or plot absolute bandwidth of antenna
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
createFeed	Create feed location for custom antenna
current	Current distribution on antenna or array surface
efficiency	Radiation efficiency of antenna
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
impedance	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	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
optimize	Optimize antenna or array using SADEA optimizer
pattern	Plot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuth	Azimuth plane radiation pattern of antenna or array
patternElevation	Elevation plane radiation pattern of antenna or array
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and/or plot resonant frequency of antenna
returnLoss	Return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
sparameters	Calculate S-parameters for antennas and antenna arrays
vswr	Voltage standing wave ratio (VSWR) of antenna or array element

Examples

Create Horn Antenna Using 2D and 3D Shapes

This example shows how to build a horn antenna using 2D and 3D shapes from the shapes catalog and customAntenna object. Follow a two step approach to create a horn antenna. Divide a horn antenna into two parts - a waveguide and a horn taper. Join them to create the horn shape. Then use this shape to create the horn antenna. Add feed to this antenna and plot its directivity pattern.

Define Dimensions of Horn

Define the dimensions of the horn and feed region in meters.

length = 0.0095;
width = 0.019;
height = 0.05;
feedHeight = 0.0048;
feedWidth = 1e-4;
feedOffset = [-0.0155 0];
flarelength = 0.102;

Create Waveguide

Use shape.Box object to create a box.

wShape = shape.Box(Length=length, Width=width,...
    Height=height);

Remove one face of the box to create a hollow box. Orient the shape appropriately.

removeFaces(wShape,2);

rotate(wShape,90,[0 0 0],[0 1 0]);

translate(wShape,[0 0 length/2]);

Create Horn Taper

Create a horn taper by linearly extruding and orienting a rectangular shape.

rect = shape.Rectangle(Length=length, Width=width);
show(rect)

hornTaper = extrudeLinear(rect,flarelength, Scale=...
[3.5579 3], NumSegments=1);
show(hornTaper)

rotate(hornTaper,90,[0 0 0],[0 1 0]);

translate(hornTaper,[height/2 0 length/2]);

Create Horn Shape and Rectangular Feed Probe

Join the waveguide and horn taper shapes to form the horn shape.

hornShape = add(wShape,hornTaper, RetainShape=1);
show(hornShape)

Create a rectangular feed probe and orient it.

feedProbe = shape.Rectangle(Length=feedHeight, Width=feedWidth);
rotate(feedProbe,90,[0 0 0],[0 1 0]);

translate(feedProbe,[feedOffset(1) feedOffset(2) feedHeight/2]);

Create Horn Antenna and Plot Directivity Pattern

Use the customAntenna object to create the horn antenna from the horn shape and add feed to it.

ant = customAntenna(Shape=hornShape);
ant = createFeed(ant,[feedOffset 0],1, FeedShape=feedProbe);
show(ant)

Plot the directivity pattern of the horn antenna at 7.847 GHz.

pattern(ant,7.847e9)

Create Custom Antenna from Horn Antenna

This example shows how to create a custom antenna from an element in the antenna catalog.

Create and Manually Mesh Horn Antenna

Create a default horn antenna and manually mesh it with a maximum edge length of 0.01 m.

ant = horn;
feedLoc = ant.FeedLocation;
m = mesh(ant,MaxEdgeLength=0.01);

Use triangulation to store the mesh data of this horn antenna.

[p,t] = exportMesh(ant);
tr = triangulation(t(:,1:4),p)

tr = 
  triangulation with properties:

              Points: [325x3 double]
    ConnectivityList: [598x4 double]

Create Custom Shape

Use shape.Custom3D to generate a horn shape from triangulation data. Visualize the shape.

hornShape = shape.Custom3D(tr);
show(hornShape)

Create a box.

hole = shape.Box(Length=0.012, Width=0.004, Height=0.005);
translate(hole,[-hole.Length 0 (hole.Length/2)+hole.Height/2]);

Cut a hole in the horn geometry by subtracting the box from it. Visualize the custom shape.

hornShape = subtract(hornShape,hole);
show(hornShape)

Create Custom Antenna

Use customAntenna to create a custom antenna from the custom horn shape. Add feed to it and visualize the antenna.

ant = customAntenna(Shape=hornShape);
[~] = createFeed(ant,feedLoc,1);
show(ant)

Create Conformal Array of Custom Microstrip Patch Antennas on Common Ground Plane

This example shows how to create a conformal array of 4 custom microstrip patch antennas on a common ground plane.

Create patch antenna shape

Create ground plane, patch, and feed shape. Add the patch and feed shapes to generate the patch antenna shape.

gnd = shape.Rectangle(Length=0.2, Width=0.2);
patch1 = shape.Rectangle(Length=0.02, Width=0.02);
feed1 = shape.Rectangle(Length=0.006, Width=0.001);
[~] = rotateY(feed1,90);
[~] = translate(feed1,[0 0 feed1.Length/2]);
[~] = translate(patch1,[0 0 feed1.Length]);
ant1 = patch1 + feed1;

Create other elements of array

Create 3 identical patch antenna shapes from the initial design.

ant2 = copy(ant1);
ant3 = copy(ant1);
ant4 = copy(ant1);
[~]= translate(ant1,[0.01 0 0]);
[~]= translate(ant2,[0.06 -0.08 0]);
[~]= translate(ant3,[0.05 0.04 0]);
[~]= translate(ant4,[-0.065 0.06 0]);

Create Conformal Array

Add all the antenna shapes and the ground plane shape to generate a conformal array configuration.

antShape = ant1 + ant2 + ant3 + ant4;
arrayShape = antShape + gnd;

Use this conformal array shape in a customAntenna and add feed points to the array elements. Visualize the conformal array.

conformalArrayAntenna= customAntenna(Shape=arrayShape);
[~] = createFeed(conformalArrayAntenna,[0.01 0 0; 0.06 -0.08 0; 0.05 0.04 0; -0.065 0.06 0],[1 1 1 1]);
show(conformalArrayAntenna)

Version History

Introduced in R2023b