planeWaveExcitation

Create plane wave excitation environment for antenna or array

Description

The planeWaveExcitation object creates an environment in which a plane wave excites an antenna or array. Plane wave excitation is a scattering solution that solves the receiver antenna problem.

Creation

Syntax

h = planeWaveExcitation

h = planeWaveExcitation(Name=Value)

Description

h = planeWaveExcitation creates an environment in which a plane wave excites an antenna or array. The default receiver antenna is a dipole that is excited by a plane wave travelling along the positive x-axis with a z-polarization.

h = planeWaveExcitation(Name=Value) sets 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 you do not specify retain their default values.

Properties

Element — Antenna or array element, or backing structure without exciter

dipole (default) | antenna object | array object

Antenna or array element, or a backing structure (cavity or reflector) without an exciter, specified as an antenna or array object from the catalog.

Note

When SolverType is set to "FMM", antennas with dielectric substrate other than "Air" cannot be used as Element.

Example: linearArray

Example: cavity(Exciter=[])

Direction — Incidence direction of plane wave

[1 0 0] (default) | three-element real vector

Incidence direction of the plane wave, specified as a three-element real vector containing the Cartesian coordinates of a point in space. The object creates the direction vector by joining a line from origin to this point.

Example: Direction=[0 0 1]

Data Types: double

Polarization — Polarization of incident electric field

[0 0 1] (default) | three-element complex vector

Polarization of the incident electric field, specified as a three-element complex vector containing the Cartesian components of the electric field in V/m. The polarization gives the orientation and magnitude of the electric field.

Example: Polarization=[0 1 0]

Data Types: double
Complex Number Support: Yes

SolverType — Solver for antenna analysis

"MoM" (default) | "FMM"

Solver for the antenna analysis, specified as one of these values:

• "MoM" --- Use the method of moments.

• "FMM" --- Use the fast multipole method.

Example: "FMM"

Data Types: string

Object Functions

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
doa	Direction of arrival of signal
design	Design prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
mesh	Mesh properties of metal, dielectric antenna, or array structure
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
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
show	Display antenna, array structures, shapes, or platform

Examples

Default Plane Wave Excitation

Excite a dipole antenna using a plane wave and view it.

h = planeWaveExcitation;
show(h)

The blue arrow shows the direction of propagation of the plane wave. The default direction is along the x-axis. The pink arrow shows polarization of the plane wave. The default polarization is perpendicular to the direction of propagation. In this case, the polarization is along the z-axis.

Feed Current of Antenna Excited by Plane Wave

Excite a dipole antenna using plane wave. Calculate the feed current at 70 MHz.

h = planeWaveExcitation 

h = 
  planeWaveExcitation with properties:

         Element: [1x1 dipole]
       Direction: [1 0 0]
    Polarization: [0 0 1]
      SolverType: 'MoM'

cur = feedCurrent(h,70e6)

cur = 0.0182 - 0.0032i

Current Distribution on Antenna

Excite a dipole antenna using a plane wave. The polarization of the wave is along the z-axis and the direction of propagation is along the negative x-axis. View the antenna.

p = planeWaveExcitation(Element=dipole,Direction=[-1 0 0],Polarization=[0 0 1]);
show(p)

Plot the current distribution on the dipole antenna at 70 MHz.

current(p,70e6);

Antenna Excited by Plane Wave in Arbitrary Direction

Consider a dipole excited by a plane wave.

p = planeWaveExcitation;
p.Direction = [0 1 1];
show(p)

For this antenna, the polarization and direction are not orthogonal to each other and thus any analysis errors out.

Use the cross-product function to find the appropriate polarization direction of such wave.

p = planeWaveExcitation;
p.Polarization = cross(p.Direction,[0 1 1]);
show(p)

Calculate the current distribution of the antenna.

current(p,75e6);

Plane Wave Excitation of Infinite Array

Excite an infinite array using a plane wave.

p = planeWaveExcitation(Element=infiniteArray)

p = 
  planeWaveExcitation with properties:

         Element: [1x1 infiniteArray]
       Direction: [1 0 0]
    Polarization: [0 0 1]
      SolverType: 'MoM'

show(p)

Analyze Cavity Structure Using Plane Wave Excitation

This example shows how to create and analyze a cavity-shaped backing structure without an exciter element using planeWaveExcitation.

Create Cavity Antenna

Create a cavity antenna operating at 1 GHz using the design function and the cavity element from the antenna catalog. Display the antenna.

f = 1e9;
ant = design(cavity,f);
figure
show(ant)

Derive Backing Structure

Derive the backing structure from the cavity antenna by specifying the 'Exciter' property as an empty array.

ant.Exciter = []

ant = 
  cavity with properties:

            Exciter: []
          Substrate: [1x1 dielectric]
             Length: 0.1690
              Width: 0.1690
             Height: 0.0634
            Spacing: 0.0634
    EnableProbeFeed: 0
          Conductor: [1x1 metal]
               Tilt: 0
           TiltAxis: [1 0 0]
               Load: [1x1 lumpedElement]

Display the backing structure.

figure
show(ant)

Mesh Backing Structure

Mesh the cavity structure with a maximum edge length of 10 mm.

figure
mesh(ant,MaxEdgeLength=10e-3)

Plot Directivity Pattern

Use the cavity backing structure as a receiver element in a plane wave excitation environment and plot its directivity at 1 GHz.

pw = planeWaveExcitation(Element=ant);
figure
pattern(pw,f)

References

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

Version History

Introduced in R2017a