lpda

Create printed log-periodic dipole array antenna

Description

Use the lpda object to create a printed log-periodic dipole array antenna. The default antenna is centered at the origin and uses an FR4 substrate. This antenna is widely used in communication and radar due to advantages such as wideband, high gain, and high directivity.

Creation

Syntax

lpdipole = lpda

lpdipole = lpda(Name,Value)

Description

lpdipole = lpda creates a printed log-periodic dipole array antenna using default property values.

lpdipole = lpda(Name,Value) sets properties using one or more name-value pairs. For example, lpdipole = lpda('BoardLength',0.2) creates a printed log-periodic dipole array with a board length of 0.2 m.

Note

Properties which are not specified retain their default values.

Properties

BoardLength — PCB length along X-axis

0.0366 (default) | scalar

Printed circuit board (PCB) length along X-axis, specified as a scalar in meters.

Example: 'BoardLength',0.2

Example: lpdipole.BoardLength = 0.2

Data Types: double

BoardWidth — PCB width along Y-axis

0.0244 (default) | two-element vector | scalar

PCB width along Y-axis, specified in meters . Width of the PCB in meter. If the value is a scalar, a rectangular board is created and if the value is a vector with 2 elements, a trapezoidal board is created. The first element represents width of the board at the shortest end of the dipole and the second element represents width at the longest end of the dipole.

Example: 'BoardWidth',[0.06 0.06]

Example: lpdipole.BoardWidth = [10e-3 12e-3]

Data Types: double

Height — PCB height along Z-axis

0.0016 (default) | scalar

PCB height along Z-axis, specified as a scalar in meters.

Example: 'Height',0.0018

Example: lpdipole.Height = 0.0018

Data Types: double

StripLineWidth — Parallel strip line width

0.0012 (default) | scalar

Width of the parallel strip, specified as a scalar in meters.

Example: 'StripLineWidth',0.0014

Example: lpdipole.StripLineWidth = 0.0014

Data Types: double

FeedLength — Distance from edge feed point to smallest dipole

0.0065 (default) | scalar

The distance from the feed point to the smallest dipole , specified as a scalar in meters.

Example: 'FeedLength',0.0055

Example: lpdipole.FeedLength = 0.0055

Data Types: double

ArmLength — Lengths of individual dipole arms

[0.0040 0.0045 0.0050 0.0056 0.0062 0.0069 0.0076 0.0085] (default) | vector

Lengths of individual dipole arms, specified as a vector with each element unit in meters.

Example: 'ArmLength',[0.0050 0.0055 0.0060 0.0066 0.0072 0.0079 0.0086 0.0095]

Example: lpdipole.ArmLength = [0.0050 0.0055 0.0060 0.0066 0.0072 0.0079 0.0086 0.0095]

Data Types: double

ArmWidth — Widths of individual dipole arms

[8.8000e-04 9.8000e-04 0.0011 0.0012 0.0013 0.0015 0.0017 0.0019] (default) | vector

Widths of individual dipole arms, specified as a vector with each element unit in meters.

Example: 'ArmWidth',[9.8000e-04 10.8000e-04 0.0021 0.0022 0.0023 0.0025 0.0027 0.0029]

Example: lpdipole.ArmWidth = [9.8000e-04 10.8000e-04 0.0021 0.0022 0.0023 0.0025 0.0027 0.0029]

Data Types: double

ArmSpacing — Spacing between individual dipole arms

[0.0027 0.0030 0.0033 0.0037 0.0041 0.0046 0.0051] (default) | vector

Spacing between individual dipole arms, specified as a vector with each element unit in meters.

Example: 'ArmSpacing',[0.0037 0.0040 0.0043 0.0047 0.0051 0.0056 0.0061]

Example: lpdipole.ArmSpacing = [0.0037 0.0040 0.0043 0.0047 0.0051 0.0056 0.0061]

Data Types: double

Substrate — Type of dielectric material

'FR4' (default) | dielectric object

Type of dielectric material used as a substrate, specified as an dielectric object. For more information, see dielectric. For more information on dielectric substrate meshing, see Meshing.

Note

The substrate dimensions must be equal to the groundplane dimensions.

Example: d = dielectric('Teflon'); 'Substrate',d

Example: d = dielectric('Teflon'); lpdipole.Substrate = d

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 feed. For more information, see lumpedElement.

Example: 'Load',lumpedelement, where lumpedelement is the object handle for the load created using lumpedElement.

Example: lpda.Load = lumpedElement('Impedance',75)

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.

Example: 'Tilt',90

Example: ant.Tilt = 90

Example: 'Tilt',[90 90],'TiltAxis',[0 1 0;0 1 1] tilts the antenna at 90 degrees about the two axes defined by the vectors.

Note

The wireStack antenna object only accepts the dot method to change its properties.

Data Types: double

TiltAxis — Tilt axis of antenna

[1 0 0] (default) | three-element vector of Cartesian coordinates | two three-element vectors of Cartesian coordinates | 'X' | 'Y' | 'Z'

Tilt axis of the antenna, specified as:

• 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, 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.

Example: 'TiltAxis',[0 1 0]

Example: 'TiltAxis',[0 0 0;0 1 0]

Example: ant.TiltAxis = 'Z'

Note

The wireStack antenna object only accepts the dot method to change its properties.

Data Types: double

Object Functions

show	Display antenna or array structure; display shape as filled patch
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
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
optimize	Optimize antenna or array using SADEA optimizer
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

Examples

Default Printed Log-Periodic Antenna

Create and view a printed log-periodic dipole array antenna.

lpdipole = lpda

lpdipole = 
  lpda with properties:

       BoardLength: 0.0366
        BoardWidth: 0.0244
            Height: 0.0016
    StripLineWidth: 0.0012
        FeedLength: 0.0065
         ArmLength: [0.0040 0.0045 0.0050 0.0056 0.0062 0.0069 0.0076 0.0085]
          ArmWidth: [1x8 double]
        ArmSpacing: [0.0027 0.0030 0.0033 0.0037 0.0041 0.0046 0.0051]
         Substrate: [1x1 dielectric]
              Tilt: 0
          TiltAxis: [1 0 0]
              Load: [1x1 lumpedElement]

show(lpdipole)

Create and View Characteristics of Tapered LPDA

Create a tapered LPDA object and plot impedance over a frequency of 5 - 8GHz. This example also shows how to plot the 3-D radiation pattern of the antenna.

lpdipole = lpda('BoardWidth',[20.37e-3 24.37e-3]);
show(lpdipole)

Plot Impedance over the specified frequency range.

freq = linspace(5e9, 8e9, 41);
figure;
impedance(lpdipole,freq)

Plot the 3-D radiation pattern at 5.8 GHz.

pattern(lpdipole,5.8e9)