Create helix or conical helix antenna on ground plane
helix object to create a helix or conical helix
antenna on a circular ground plane. The helix antenna is a common choice in satellite
The width of the strip is related to the diameter of an equivalent cylinder by the equation
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
xy- 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
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.
ant — Helix antenna
Helix antenna, returned as a
Radius — Radius of turns
0.0220 (default) | positive scalar integer | two-element vector
Radius of the turns, specified as a positive scalar integer in meters or a two element vector with each element unit in meters. In the two-element vector, the first element specifies the bottom radius and the second element specifies the top radius of the conical helix antenna.
ant.Radius = [28e-03 30e-03]
Width — Strip width
1.0000e-03 (default) | scalar
Strip width, specified as a scalar in meters.
Strip width should be less than
ant.Width = 5
Turns — Number of turns of helix
3 (default) | scalar
Number of turns of the helix, specified as a scalar.
ant.Turns = 2
Spacing — Spacing between turns
0.0350 (default) | scalar
Spacing between turns, specified as a scalar in meters.
ant.Spacing = 1.5
WindingDirection — Direction of helix turns (windings)
Direction of helix turns (windings), specified as
ant.WindingDirection = CW
GroundPlaneRadius — Ground plane radius
0.0750 (default) | scalar in meters
Ground plane radius, specified as a scalar in meters. By default, the ground plane is on the X-Y plane and is symmetrical about the origin.
ant.GroundPlaneRadius = 2.05
FeedStubHeight — Feeding stub height from ground
1.0000e-03 (default) | scalar
Feeding stub height from ground, specified as a scalar in meters.
ant.FeedStubHeight = 2.000e-03
The default value is chosen to allow backward compatibility.
Substrate — Type of dielectric material
'Air' (default) |
Type of dielectric material used as the substrate, specified as a
dielectric object. You can specify only one dielectric layer in the
helix object. When using the
Substrate property, specify the same radius for all
the turns. When using a dielectric material other than air, the number of
turns in the helix should be greater than 1. For more information, see
dielectric. For more
information on dielectric substrate meshing, see Meshing.
d = dielectric('Teflon'); hx =
d = dielectric('Teflon'); hx.Substrate =
Conductor — Type of metal material
'PEC' (default) |
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
metal. For more information on metal conductor meshing, see
m = metal('Copper');
m = metal('Copper'); ant.Conductor =
Load — Lumped elements
[1x1 lumpedElement] (default) | lumped element object
Lumped elements added to the antenna feed, specified as a lumped element
object. You can add a load anywhere on the surface of the antenna. By
default, the load is at the origin. For more information, see
lumpedelement is the object for the load created
Tilt — Tilt angle of antenna
0 (default) | scalar | vector
Tilt angle of the antenna in degrees, specified as a scalar or vector. For more information, see Rotate Antennas and Arrays.
TiltAxis=[0 1 0;0 1 1]
tilts the antenna at 90 degrees about the two axes defined by the
TiltAxis — Tilt axis of antenna
[1 0 0] (default) | three-element vector | 2-by-3 matrix |
Tilt axis of the antenna, specified as one of these values:
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, specified as a 2-by-3 matrix corresponding to two three-element vectors of Cartesian coordinates. In this case, the antenna rotates around the line joining the two points.
"z"to describe a rotation about the x-, y-, or z-axis, respectively.
For more information, see Rotate Antennas and Arrays.
[0 1 0]
[0 0 0;0 1 0]
|Display antenna, array structures, shapes, or platform|
|Display information about antenna or array|
|Axial ratio of antenna|
|Beamwidth of antenna|
|Charge distribution on antenna or array surface|
|Current distribution on antenna or array surface|
|Design prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects|
|Radiation efficiency of antenna|
|Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays|
|Input impedance of antenna or scan impedance of array|
|Mesh properties of metal, dielectric antenna, or array structure|
|Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry|
|Optimize antenna or array using SADEA optimizer|
|Plot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array|
|Azimuth plane radiation pattern of antenna or array|
|Elevation plane radiation pattern of antenna or array|
|Calculate and plot radar cross section (RCS) of platform, antenna, or array|
|Return loss of antenna or scan return loss of array|
|Calculate S-parameters for antennas and antenna arrays|
|Voltage standing wave ratio (VSWR) of antenna or array element|
Create and View Helix Antenna
Create and view a helix antenna that has a 28 mm turn radius, 1.2 mm strip width, and 4 turns.
hx = helix('Radius',28e-3,'Width',1.2e-3,'Turns',4)
hx = helix with properties: Radius: 0.0280 Width: 0.0012 Turns: 4 Spacing: 0.0350 WindingDirection: 'CCW' FeedStubHeight: 1.0000e-03 GroundPlaneRadius: 0.0750 Substrate: [1x1 dielectric] Conductor: [1x1 metal] Tilt: 0 TiltAxis: [1 0 0] Load: [1x1 lumpedElement]
Radiation Pattern of Helix Antenna
Plot the radiation pattern of a helix antenna.
hx = helix(Radius=28e-3,Width=1.2e-3,Turns=4); pattern(hx,1.8e9);
Calculate Spacing of Helix Antenna with Varying Radius
Calculate the spacing of a helix that has a pitch of 12 degrees and a radius that varies from 20 mm to 22 mm in steps of 0.5 mm.
s = helixpitch2spacing(12,20e-3:0.5e-3:22e-3)
s = 1×5 0.0267 0.0274 0.0280 0.0287 0.0294
Radiation Pattern of Helix Antenna
Plot the radiation pattern of a helix antenna with transparency specified as 0.5.
p = PatternPlotOptions
p = PatternPlotOptions with properties: Transparency: 1 SizeRatio: 0.9000 MagnitudeScale:  AntennaOffset: [0 0 0]
p.Transparency = 0.5; ant = helix; pattern(ant,2e9,patternOptions=p)
To understand the effect of Transparency, chose
Overlay Antenna in the radiation pattern plot.
This option overlays the helix antenna on the radiation pattern.
Helix Antenna with Dielectric Substrate
Create a custom helix antenna with a Teflon dielectric substrate.
d = dielectric('Teflon'); hx = helix('Width',0.815e-3,'Turns',6,'Radius',9.3e-3,'Spacing',12.4e-3,'Substrate',d)
hx = helix with properties: Radius: 0.0093 Width: 8.1500e-04 Turns: 6 Spacing: 0.0124 WindingDirection: 'CCW' FeedStubHeight: 1.0000e-03 GroundPlaneRadius: 0.0750 Substrate: [1x1 dielectric] Conductor: [1x1 metal] Tilt: 0 TiltAxis: [1 0 0] Load: [1x1 lumpedElement]
View the helix antenna.
 Balanis, C.A. Antenna Theory. Analysis and Design, 3rd Ed. New York: Wiley, 2005.
 Volakis, John. Antenna Engineering Handbook, 4th Ed. New York: Mcgraw-Hill, 2007.
 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.
 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.
 B. Young, K. A. O'Connor and R. D. Curry, “Reducing the size of helical antennas by means of dielectric loading,” 2011 IEEE Pulsed Power Conference, 2011, pp. 575-579, doi: 10.1109/PPC.2011.6191490
Introduced in R2015a