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yagiUda

Create Yagi-Uda array antenna

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Description

The default yagiUda class creates a classic Yagi-Uda array comprised of an exciter, reflector, and N- directors along the z-axis resonating around 278 MHz. The reflector and directors create a traveling wave structure that results in a directional radiation pattern.

The exciter, reflector, and directors have equal widths and are related to the diameter of an equivalent cylindrical structure by the equation

w=2d=4r

where:

  • d is the diameter of equivalent cylinder

  • r is the radius of equivalent cylinder

For a given cylinder radius, use the cylinder2strip utility function to calculate the equivalent width. A typical Yagi-Uda antenna array uses folded dipole as an exciter, due to its high impedance. The Yagi-Uda is center-fed and the feed point coincides with the origin. In place of a folded dipole, you can also use a planar dipole as an exciter.

Creation

Syntax

y = yagiUda
y = yagiUda(Name=Value)

Description

y = yagiUda creates a half-wavelength Yagi-Uda array antenna along the Z-axis with default property values. The default Yagi-Uda uses folded dipole as three directors, one reflector, and a folded dipole as an exciter. The default dimensions are chosen for an operating frequency of around 278 MHz.

y = yagiUda(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 that you do not specify, retain their default values.

For example, y = yagiUda(Exciter=dipole) creates an Yagi-Uda antenna with a dipole exciter.

example

Properties

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Antenna type used as exciter, specified as a dipoleFolded object or dipole object.

Example: dipole

Total number of director elements, specified as a scalar.

Note

Number of director elements should be less than or equal to 20.

Example: 13

Data Types: double

Director length, specified as a scalar or vector in meters.

Example: [0.4 0.5]

Data Types: double

Spacing between directors, specified as a scalar or vector in meters.

Example: [0.4 0.5]

Data Types: double

Reflector length, specified as a scalar in meters.

Example: 0.3

Data Types: double

Spacing between exciter and reflector, specified as a scalar in meters.

Example: 0.4

Data Types: double

Type of the metal used as a conductor, specified as a metal material object. You can choose any metal from the MetalCatalog or specify a metal of your choice. For more information, see metal. For more information on metal conductor meshing, see Meshing.

Example: m = metal('Copper'); 'Conductor',m

Example: m = metal('Copper'); ant.Conductor = m

Lumped elements added to the antenna feed, specified as a lumped element object. For more information, see lumpedElement.

Example: 'Load',lumpedelement. lumpedelement is the object for the load created using lumpedElement.

Example: yu.Load = lumpedElement('Impedance',75)

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

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

Object Functions

axialRatioCalculate and plot axial ratio of antenna or array
bandwidthCalculate and plot absolute bandwidth of antenna or array
beamwidthBeamwidth of antenna
chargeCharge distribution on antenna or array surface
currentCurrent distribution on antenna or array surface
designDesign prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiencyCalculate and plot radiation efficiency of antenna or array
EHfieldsElectric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrentCalculate current at feed for antenna or array
impedanceCalculate and plot input impedance of antenna or scan impedance of array
infoDisplay information about antenna, array, or platform
memoryEstimateEstimate memory required to solve antenna or array mesh
meshMesh properties of metal, dielectric antenna, or array structure
meshconfigChange meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwriteWrite antenna or array analysis data to MSI planet file
optimizeOptimize antenna or array using SADEA optimizer
patternPlot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuthAzimuth plane radiation pattern of antenna or array
patternElevationElevation plane radiation pattern of antenna or array
peakRadiationCalculate and mark maximum radiation points of antenna or array on radiation pattern
rcsCalculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequencyCalculate and plot resonant frequency of antenna
returnLossCalculate and plot return loss of antenna or scan return loss of array
showDisplay antenna, array structures, shapes, or platform
sparametersCalculate S-parameters for antenna or array
stlwriteWrite mesh information to STL file
vswrCalculate and plot voltage standing wave ratio (VSWR) of antenna or array element

Examples

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Open Live Script

Create and view a Yagi-Uda array antenna with 13 directors.

y = yagiUda(NumDirectors=13);
show(y)

Figure contains an axes object. The axes object with title yagiUda antenna element, xlabel x (m), ylabel y (m) contains 5 objects of type patch, surface. These objects represent PEC, feed.

Open Live Script

Plot the radiation pattern of a Yagi-Uda array antenna at a frequency of 300 MHz.

y = yagiUda(NumDirectors=13);
pattern(y,300e6)

Figure contains 2 axes objects and other objects of type uicontrol. Axes object 1 contains 5 objects of type patch, surface. Hidden axes object 2 contains 17 objects of type surface, line, text, patch.

Open Live Script

Calculate the width of the strip approximation to a cylinder of radius 20 mm.

w = cylinder2strip(20e-3)
w = 
0.0800

References

[1] Balanis, C.A. Antenna Theory. Analysis and Design, 3rd Ed. New York: Wiley, 2005.

Version History

Introduced in R2015a

See Also

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