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Create helical dipole antenna

The `dipoleHelix `

object is a helical
dipole antenna. The antenna is typically center fed. You can move
the feed along the antenna length using the feed offset property.
Helical dipoles are used in satellite communications and wireless
power transfers.

The width of the strip is related to the diameter of an equivalent cylinder by this equation

$$w=2d=4r$$

*w*is the width of the strip.*d*is the diameter of an equivalent cylinder.*r*is the radius of an equivalent cylinder.

For a given cylinder radius, use the `cylinder2strip`

utility
function to calculate the equivalent width. The default helical dipole
antenna is center-fed. The circular ground plane is on the X-Y plane.
Commonly, helical dipole antennas are used in axial mode. In this
mode, the helical dipole circumference is comparable to the operating
wavelength, and has maximum directivity along its axis. In normal
mode, the helical dipole radius is small compared to the operating
wavelength. In this mode, the helical dipole radiates broadside, that
is, in the plane perpendicular to its axis. The basic equation for
the helical dipole antenna is:

$$\begin{array}{l}x=r\mathrm{cos}(\theta )\\ y=r\mathrm{sin}(\theta )\\ z=S\theta \end{array}$$

where:

*r*is the radius of the helical dipole.*θ*is the winding angle.*S*is the spacing between turns.

For a given pitch angle in degrees, use the `helixpitch2spacing`

utility function
to calculate the spacing between the turns in meters.

`dh = dipoleHelix`

`dh = dipoleHelix(Name,Value)`

creates
a helical dipole antenna. The default antenna operates around 2 GHz.`dh`

= dipoleHelix

creates
a helical dipole antenna, with additional properties specified by
one or more name–value pair arguments. `dh`

= dipoleHelix(Name,Value)`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.

`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 for resonance at specified frequency |

`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 |

`pattern` | Radiation pattern 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 |

[1] Balanis, C. A. *Antenna Theory. Analysis and
Design*. 3rd Ed. Hoboken, NJ: John Wiley & Sons, 2005.

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

`cylinder2strip`

| `helix`

| `helixpitch2spacing`

| `monopole`

| `pifa`

| `spiralArchimedean`

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