dipoleFolded

Create folded dipole antenna

Description

The dipolefolded object is a folded dipole antenna on the xy- plane.

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.

dF = dipoleFolded(Name,Value) creates a half-wavelength folded dipole antenna with additional properties specified by one or more name-value pair arguments. Name is the property name and Value is the corresponding value. You can specify several name-value pair arguments in any order as Name1, Value1, ..., NameN, ValueN. Properties not specified retain their default values.

Properties

Length — Folded dipole length

2 (default) | scalar

Folded dipole length, specified as a scalar in meters. By default, the length is chosen for an operating frequency of 70.5 MHz.

Example: 'Length',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: 'Width',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: 'Spacing',3

Data Types: double

Conductor — Type of metal material

'PEC' (default) | metal object

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

Load — Lumped elements

[1x1 lumpedElement] (default) | lumped element object

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

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

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

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
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
design	Design prototype antenna or arrays for resonance around specified frequency
efficiency	Radiation efficiency of antenna
EHfields	Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
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
optimize	Optimize antenna or array using SADEA optimizer
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
rcs	Calculate and plot radar cross section (RCS) of platform, 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

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