# dipoleFolded

Create folded dipole antenna

## Description

The dipolefolded object is a folded dipole antenna on the X-Y 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 X-Y plane. When compared to the planar dipole, the folded dipole structure increases the input impedance of the antenna.

## Creation

### Description

dF = dipoleFolded creates a half-wavelength folded dipole antenna.

example

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

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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

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

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

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 a lumped element object handle. For more information, see lumpedElement.

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

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: ant.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

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'.

Example: 'TiltAxis',[0 1 0]

Example: 'TiltAxis',[0 0 0;0 1 0]

Example: ant.TiltAxis = 'Z'

Note

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

Data Types: double

## Object Functions

 show Display antenna or array structure; display shape as filled patch info Display information about antenna or array axialRatio Axial ratio of antenna beamwidth Beamwidth of antenna charge Charge distribution on metal or dielectric antenna or array surface current Current distribution on metal or dielectric antenna or array surface design Design prototype antenna or arrays for resonance at 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 or 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 returnLoss Return loss of antenna; scan return loss of array sparameters S-parameter object vswr Voltage standing wave ratio of antenna

## Examples

collapse all

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]

show(df)

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]

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.

### Topics

Introduced in R2015a