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 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
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
Strip width, specified as a scalar in meters.
Strip width should be less than
ant.Width = 5
Turns— Number of turns of helix
Number of turns of the helix, specified as a scalar.
ant.Turns = 2
Spacing— Spacing between turns
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
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
Feeding stub height from ground, specified as a scalar in meters. B
ant.FeedStubHeight = 2.000e-03
The default value is chosen to allow backward compatibility.
Load— Lumped elements
Lumped elements added to the antenna feed, specified as a lumped element
object handle. 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 handle for the load
Tilt— Tilt angle of antenna
0(default) | scalar | vector
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.
'TiltAxis',[0 1 0;0 1 1]
tilts the antenna at 90 degree about two axes, defined by vectors.
TiltAxis— Tilt axis of antenna
[1 0 0](default) | three-element vector of Cartesian coordinates | two three-element vectors of Cartesian coordinates |
Tilt axis of the antenna, specified as:
Three-element vectors 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, 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'.
For more information, see Rotate Antennas and Arrays.
'TiltAxis',[0 1 0]
'TiltAxis',[0 0 0;0 1 0]
ant.TiltAxis = 'Z'
|Display antenna or array structure; Display shape as filled patch|
|Display information about antenna or array|
|Axial ratio of antenna|
|Beamwidth of antenna|
|Charge distribution on metal or dielectric antenna or array surface|
|Current distribution on metal or dielectric antenna or array surface|
|Design prototype antenna or arrays for resonance at specified frequency|
|Electric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays|
|Input impedance of antenna; scan impedance of array|
|Mesh properties of metal or dielectric antenna or array structure|
|Change mesh mode of antenna structure|
|Radiation pattern and phase of antenna or array; Embedded pattern of antenna element in array|
|Azimuth pattern of antenna or array|
|Elevation pattern of antenna or array|
|Return loss of antenna; scan return loss of array|
|Voltage standing wave ratio of 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 Tilt: 0 TiltAxis: [1 0 0] Load: [1x1 lumpedElement]
Plot the radiation pattern of a helix antenna.
hx = helix('Radius',28e-3,'Width',1.2e-3,'Turns',4); pattern(hx,1.8e9);
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
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.
 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.