Create J-dipole antenna
dipoleJ object to create a J-dipole on the Y-Z
plane. The antenna contains a half-wavelength radiator and a quarter-wavelength stub. By
default, the antenna dimensions are for an operating frequency of 144
jdipole = dipoleJ creates a J-dipole antenna for an
operating frequency of 144 MHz.
jdipole = dipoleJ(Name,Value) creates a J-dipole
antenna with additional properties specified by one or more name-value pair
arguments. For example,
jdipole = dipoleJ('Width',0.2)
creates a J-dipole with a strip width of 0.2 m. Enclose each property name
RadiatorLength— Radiator length
0.9970(default) | scalar
Radiator length, specified as a scalar in meters.
jdipole.RadiatorLength = 0.9
StubLength— Parallel line stub length
0.4997(default) | scalar
Parallel line stub length, specified as a scalar in meters.
jdipole.StubLength = 0.3
Width— Strip width
0.0200(default) | scalar
Strip width, specified as a scalar in meters.
jdipole.StripWidth = 0.0500
Spacing— Space between the stub and the radiator
0.0460(default) | scalar
Space between the parallel line stub and the radiator, specified as a scalar in meters.
jdipole.Spacing = 0.0500
FeedOffset— Signed distance to feed from base of stub on large arm
Signed distance to the feed from the base of stub on the large arm, specified as a scalar in meters.
jdipole.FeedOffset = 0.0345
Load— Lumped elements
lumpedElement] (default) | lumped element object handle
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|
|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 default J-dipole antenna.
d = dipoleJ
d = dipoleJ with properties: RadiatorLength: 0.9970 StubLength: 0.4997 Spacing: 0.0460 Width: 0.0200 FeedOffset: -0.6994 Tilt: 0 TiltAxis: [1 0 0] Load: [1x1 lumpedElement]
Create and view a J-dipole antenna with the following specifications:
Radiator length = 0.978 m
Stub length = 0.485 m
FeedOffset = 0.049 m
dj = dipoleJ('RadiatorLength',0.978,'StubLength',0.485, ... 'FeedOffset',0.070); show(dj)
Calculate the impedance of the antenna over a frequency span 140MHz - 150MHz.