dipoleFolded

Create folded dipole antenna

Description

The default dipolefolded object is a folded dipole antenna on the xy-plane resonating around 70 MHz.

The width of the dipole is related to the diameter of an equivalent cylindrical dipole by the equation

$$w=2d=4r$$

, where

• d is the diameter of the equivalent cylindrical pole

• r is the radius of the equivalent cylindrical pole.

For a given cylinder radius, use the cylinder2strip utility function to calculate the equivalent width. The default folded dipole is center-fed. The feed point of the dipole coincides with the origin. The origin is located on the xy- plane. When compared to the planar dipole, the folded dipole structure increases the input impedance of the antenna.

Creation

Syntax

df = dipoleFolded

df = dipoleFolded(Name=Value)

Description

df = dipoleFolded creates a half-wavelength folded dipole antenna. The default dimensions are chosen for an operating frequency of around 70 MHz.

df = dipoleFolded(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, df = dipoleFolded(Length=4) creates a folded dipole antenna with a length of 4 m. and default values for other properties.

Properties

Length — Folded dipole length

2 (default) | scalar

Folded dipole length, specified as a scalar in meters.

Example: 3

Data Types: double

Width — Folded dipole width

0.0040 (default) | scalar

Folded dipole width, specified as a scalar in meters.

Note

Folded dipole width should be less than Length/20 and greater than Length/1001. [2]

Example: 0.05

Data Types: double

Spacing — Shorting stub lengths at dipole ends

0.0245 (default) | scalar

Shorting stub lengths at dipole ends, specified as a scalar in meters. The value must be less than Length/50.

Example: 3

Data Types: double

Conductor — Type of metal material

metal("PEC") (default) | metal object

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

Example: metal("Copper")

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.

Example: Load=lumpedElement(Impedance=75)

Example: antenna.Load = lumpedElement(Impedance=75)

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

Object Functions

axialRatio	Calculate and plot axial ratio of antenna or array
bandwidth	Calculate and plot absolute bandwidth of antenna or array
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
current	Current distribution on antenna or array surface
design	Design prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiency	Calculate and plot radiation efficiency of antenna or array
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrent	Calculate current at feed for antenna or array
impedance	Calculate and plot 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
msiwrite	Write antenna or array analysis data to MSI planet file
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
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and plot resonant frequency of antenna
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
sparameters	Calculate S-parameters for antenna or array
stlwrite	Write mesh information to STL file
vswr	Calculate and plot voltage standing wave ratio (VSWR) of antenna or array element
wireStack	Create single or multi-feed wire antenna

Examples

Create and View Folded Dipole Antenna

Create and view a folded dipole with 2 m length and 0.05 m width.

df = dipoleFolded(Length=2, Width=0.05)

df = 
  dipoleFolded with properties:

       Length: 2
        Width: 0.0500
      Spacing: 0.0245
    Conductor: [1x1 metal]
         Tilt: 0
     TiltAxis: [1 0 0]
         Load: [1x1 lumpedElement]

show(df)

Radiation Pattern of Folded Dipole Antenna

Plot the radiation pattern of a folded dipole at 70.5 MHz.

df = dipoleFolded

df = 
  dipoleFolded with properties:

       Length: 2
        Width: 0.0180
      Spacing: 0.0245
    Conductor: [1x1 metal]
         Tilt: 0
     TiltAxis: [1 0 0]
         Load: [1x1 lumpedElement]

pattern(df, 70.5e6);

References

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

[2] Volakis, John. Antenna Engineering Handbook, 4th Ed. New York: Mcgraw-Hill, 2007.

Version History

Introduced in R2015a