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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

Syntax

dF = dipoleFolded
dF = dipoleFolded(Name,Value)

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

expand all

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

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 antenna, specified as a scalar or vector with each element unit in degrees.

Example: 'Tilt',90

Example: 'Tilt',[90 90 0]

Data Types: double

Tilt axis of the antenna, specified as:

  • A three-element vector of Cartesian coordinates in meters. In this case, each vector starts at the origin and lies along the specified points on the X, Y, and Z axes.

  • Two points in space as three-element vectors of Cartesian coordinates. In this case, the antenna rotates along the line joining the two points.

  • A string input for simple rotations around the principal planes, X, Y, or Z.

For more information see, Rotate Antenna and Arrays

Example: 'TiltAxis',[0 1 0]

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

Example: 'TiltAxis','Z'

Data Types: double

Object Functions

showDisplay antenna or array structure; Display shape as filled patch
infoDisplay information about antenna or array
axialRatioAxial ratio of antenna
beamwidthBeamwidth of antenna
chargeCharge distribution on metal or dielectric antenna or array surface
currentCurrent distribution on metal or dielectric antenna or array surface
designDesign prototype antenna for resonance at specified frequency
EHfieldsElectric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
impedanceInput impedance of antenna; scan impedance of array
meshMesh properties of metal or dielectric antenna or array structure
meshconfigChange mesh mode of antenna structure
patternRadiation pattern of antenna or array; Embedded pattern of antenna element in array
patternAzimuthAzimuth pattern of antenna or array
patternElevationElevation pattern of antenna or array
returnLossReturn loss of antenna; scan return loss of array
sparametersS-parameter object
vswrVoltage standing wave ratio of antenna

Examples

expand all

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

df = dipoleFolded('Length',2,'Width',0.05)
df = 
  dipoleFolded with properties:

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

show(df)

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

df = dipoleFolded
pattern(df, 70.5e6);
df = 

  dipoleFolded with properties:

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

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.

Introduced in R2015a

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