customAntennaStl

Create custom antenna 3-D geometry using STL files

Since R2020a

Description

The customAntennaStl object creates a 3-D antenna geometry and mesh using Stereolithography (STL) files. The STL files are used to define any 3-D surface in the form of points and triangles.

Creation

Syntax

ca = customAntennaStl

Description

ca = customAntennaStl returns a 3D antenna represented by a custom geometry, based on the STL file specified.

Properties

FileName — Name the STL file

'[]' (default) | character vector

Name of the STL file where the structure resides, specified as character vector.

Example: antenna = customAntennaStl('FileName','plate.stl')

Example: antenna = customAntennaStl; antenna.FileName = 'plate.stl'

Data Types: char

Units — Units used in STL file

'm' (default) | 'mm' | 'cm' | 'um' | 'ft' | 'in' | character vector

Units used in STL file, specified as a character vector.

Example: 'Units','mm'

Data Types: char

FeedLocation — Antenna feed location in Cartesian coordinates

[] (default) | three-element real vector

This property is read-only.

Antenna feed location in Cartesian coordinates, specified as a three-element real vector. The three-element vector are the X-, Y-, and Z-coordinates, respectively.

Note

FeedLocation property displays the antenna feed location you set using the createFeed function.

Data Types: double

AmplitudeTaper — Excitation amplitude of antenna elements

1 (default) | scalar double

Excitation amplitude of antenna elements, specified as scalar double.

Example: 'AmplitudeTaper','1.8'

Data Types: double

PhaseShift — Phase shift for antenna elements

0 (default) | scalar

Phase shift for the antenna elements, specified as a scalar in degrees.

Example: 'PhaseShift',10

Data Types: double

UseFileAsMesh — Use stl file as mesh

0 (default) | 1

Use the STL file directly as a mesh for analysis. The value can be either 0 or 1.

Example: 'UseFileAsMesh',1

Data Types: logical

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: Tilt=[90 90],TiltAxis=[0 1 0;0 1 1] tilts the antenna at 90 degrees about the two axes defined by the vectors.

Note

The wireStack antenna object only accepts the dot method to change its properties.

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: TiltAxis = 'Z'

Data Types: double

Object Functions

show	Display antenna, array structures or shapes
info	Display information about antenna or array
createFeed	Create feed location for customAntennaStl object
axialRatio	Axial ratio of antenna
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
current	Current distribution on antenna or array surface
impedance	Input impedance of antenna; scan impedance of array
mesh	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change mesh mode of antenna structure
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
returnLoss	Return loss of antenna; scan return loss of array
sparameters	Calculate S-parameter for antenna and antenna array objects
vswr	Voltage standing wave ratio of antenna
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array
EHfields	Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays

Examples

Create and Display Custom 3-D Antenna

Create a custom 3-D antenna using customAntennaStl object.

c = customAntennaStl('Filename','plateMesh.stl','Units','m');

Create antenna feed and calculate the antenna impedance at 110 GHz.

c.createFeed([0,0,0],1);
Z = impedance(c,110e6)

Z = 0.0287 +34.3704i

disp(c)

  customAntennaStl with properties:

          FileName: 'plateMesh.stl'
             Units: 'm'
      FeedLocation: [0 0 0]
    AmplitudeTaper: 1
        PhaseShift: 0
     UseFileAsMesh: 0
              Tilt: 0
          TiltAxis: [1 0 0]

Display the structure of custom 3-D antenna.

show(c)

Create Antenna Feed in Custom Antenna STL Using Command Line Interface

Create a customAntennaStl object using the specified STL file.

ant = customAntennaStl

ant = 
  customAntennaStl with properties:

          FileName: []
             Units: 'm'
      FeedLocation: []
    AmplitudeTaper: 1
        PhaseShift: 0
     UseFileAsMesh: 0
              Tilt: 0
          TiltAxis: [1 0 0]

ant.FileName ='patchMicrostrip_ColumnFeed.stl'

ant = 
  customAntennaStl with properties:

          FileName: 'patchMicrostrip_ColumnFeed.stl'
             Units: 'm'
      FeedLocation: []
    AmplitudeTaper: 1
        PhaseShift: 0
     UseFileAsMesh: 0
              Tilt: 0
          TiltAxis: [1 0 0]

Specify FeedLocation and NumEdges in the createFeed function. The edges are selected based on distance between feed location and midpoints of the edges. Edges can be single feed or a closed polygon.

ant.createFeed([-0.018750000000000 0 0],8)
show (ant)

Plot the current distribution at 1.75 GHz.

figure
current(ant,1.75e9,'Scale','log')

Calculate the impedance at 1.75 GHz.

z = impedance(ant,1.75e9)

z = 85.7298 -52.7332i

Create Antenna Feed Using UI Figure Window

Create a customAntennaStl object.

ant = customAntennaStl;

Import the STL files.

ant.FileName = 'patchMicrostrip_ColumnFeed.stl';

Create the antenna feed using UI figure window.

createFeed(ant);

The UI figure window consists of two panes, the Slice Antenna panel and the Add Feed pane.

Click the Slicer Mode, then click YZ to select that as the plane along which to slice your antenna.

Select the region you want to hide and then click Hide to hide the selected region.

Repeat the process until you reach the region of interest.

Select Select a Feeding Edge or Polygon under the Add Feed pane to select the desired feeding edge or feeding polygon.

Select the edges of the column that forms a closed polygon. The selected edges must be connected to other edges, else the UI figure window will display an error.

Click OK to define the selected edges as feeding edges and the structure with the feed is displayed.

The FeedLocation is displayed.

Verify the location of the antenna feed in the commandline.

ant

ant = 
  customAntennaStl with properties:

          FileName: 'patchMicrostrip_ColumnFeed.stl'
             Units: 'm'
      FeedLocation: []
    AmplitudeTaper: 1
        PhaseShift: 0
     UseFileAsMesh: 0
              Tilt: 0
          TiltAxis: [1 0 0]

References

[1] Balanis, C. A. Antenna Theory. Analysis and Design. 3rd Ed. Hoboken, NJ: John Wiley & Sons, 2005.

Version History

Introduced in R2020a