Create helix or conical helix antenna on ground plane

Use the `helix`

object to create a helix or conical helix
antenna on a circular ground plane. The helix antenna is a common choice in satellite
communication.

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

$$w=2d=4r$$

where:

*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 helix antenna is end-fed. The circular ground plane is on the X-Y plane.
Commonly, helix antennas are used in axial mode. In this mode, the helix circumference
is comparable to the operating wavelength and the helix has maximum directivity along
its axis. In normal mode, the helix radius is small compared to the operating
wavelength. In this mode, the helix radiates broadside, that is, in the plane
perpendicular to its axis. The basic equation for the helix 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 helix.*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.

In an array of helix antennas, the circular ground plane of the helix is converted to rectangular ground plane.

`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 |

`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 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 |

[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.

[3] Zhang, Yan, Q. Ding, J. Chen, S. Lu, Z. Zhu and L. L. Cheng. “A
Parametric Study of Helix Antenna for S-Band Satellite Communications.”
* 9th International Symposium on Antenna Propagation and EM Theory
(ISAPE)*. 2010, pp. 193–196.

[4] Djordjevic, A.R., Zajic, A.G., Ilic, M. M., Stuber, G.L. “Optimization
of Helical antennas (Antenna Designer's Notebook)” * IEEE Antennas and
Propagation Magazine*. December, 2006, pp. 107, pp.115.

`cylinder2strip`

| `helixMultifilar`

| `helixpitch2spacing`

| `monopole`

| `pifa`

| `spiralArchimedean`