Create Yagi-Uda array antenna
yagiUda class creates a classic Yagi-Uda array
comprised of an exciter, reflector, and N- directors along the
z-axis. The reflector and directors create a traveling wave structure that results in a
directional radiation pattern.
The exciter, reflector, and directors have equal widths and are related to the diameter of an equivalent cylindrical structure by the equation
d is the diameter of equivalent cylinder
r is the radius of equivalent cylinder
For a given cylinder radius, use the
cylinder2strip utility function to calculate the equivalent width. A
typical Yagi-Uda antenna array uses folded dipole as an exciter, due to its high
impedance. The Yagi-Uda is center-fed and the feed point coincides with the origin. In
place of a folded dipole, you can also use a planar dipole as an exciter.
half-wavelength Yagi-Uda array antenna along the Z-axis. The default
Yagi-Uda uses folded dipole as three directors, one reflector, and a folded
dipole as an exciter. By default, the dimensions are chosen for an operating
frequency of 300 MHz.
yu = yagiUda
half-wavelength Yagi-Uda array antenna, with additional properties specified
by one or more name-value pair arguments.
yu = yagiUda(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
ValueN. Properties not specified retain default
Exciter— Antenna type used as exciter
Antenna Type used as exciter, specified as the comma-separated pair
'Exciter' and an object.
NumDirectors— Total number of director elements
Total number of director elements, specified as a scalar.
Number of director elements should be less than or equal to 20.
DirectorLength— Director length
Director length, specified as a scalar or vector in meters.
DirectorSpacing— Spacing between directors
Spacing between directors, specified as a scalar or vector in meters.
ReflectorLength— Reflector length
Reflector length, specified as a scalar in meters.
ReflectorSpacing— Spacing between exciter and reflector
Spacing between exciter and reflector, specified as a scalar in meters.
Load— Lumped elements
Lumped elements added to the antenna feed, specified as a lumped element
object handle. 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 Yagi-Uda array antenna with 13 directors.
y = yagiUda('NumDirectors',13); show(y)
Plot the radiation pattern of a Yagi-Uda array antenna at a frequency of 30 0MHz.
y = yagiUda('NumDirectors',13); pattern(y,300e6)
Calculate the width of the strip approximation to a cylinder of radius 20 mm.
w = cylinder2strip(20e-3)
w = 0.0800
 Balanis, C.A. Antenna Theory. Analysis and Design, 3rd Ed. New York: Wiley, 2005.