pattern

Radiation pattern and phase of antenna or array; Embedded pattern of antenna element in array

Syntax

pattern(object,frequency)

pattern(object,frequency,azimuth,elevation)

pattern(___,Name,Value)

[pat,azimuth,elevation] = pattern(object,frequency,azimuth,elevation)

[pat,azimuth,elevation] = pattern(___,Name,Value)

Description

pattern(object,frequency) plots the 3-D radiation pattern of the antenna or array object over a specified frequency. By default, in Antenna Toolbox™, the far-field radius is set to 100λ.

pattern(object,frequency,azimuth,elevation) plots the radiation pattern of the antenna or array object using the specified azimuth and elevation angles.

pattern(___,Name,Value) uses additional options specified by one or more Name, Value pair arguments. You can use any of the input arguments from previous syntaxes.

Use the 'ElementNumber' and 'Termination' property to calculate the embedded pattern of the antenna element in an array connected to a voltage source. The voltage source model consists of an ideal voltage source of 1 volt in series with a source impedance. The embedded pattern includes the effect of mutual coupling due to the other antenna elements in the array.

[pat,azimuth,elevation] = pattern(object,frequency,azimuth,elevation) returns the pattern value, pat, value of an antenna or array object at specified frequency. azimuth and elevation are the angles at which the pattern function calculates the directivity.

[pat,azimuth,elevation] = pattern(___,Name,Value) uses additional options specified by one or more Name,Value pair arguments.

Examples

Calculate Radiation Pattern of Array

Calculate radiation pattern of default linear array for a frequency of 70 MHZ.

l = linearArray;
pattern(l,70e6)

Radiation Pattern of Helix in X-Z Plane

Plot the radiation pattern of a helix antenna in xz-plane.

h = helix; 
pattern (h, 2e9, 0, 1:1:360);

[pat,azimuth,elevation] = pattern (h, 2e9, 0, 1:1:360);

Compute the maximum and the minimum value of the radiation pattern and the elevation angle.

pattern_max = max(max(pat))

pattern_max = 8.6905

pattern_min = min(min(pat))

pattern_min = -11.2357

elevation_max = max(elevation) 

elevation_max = 360

elevation_min = min(elevation) 

elevation_min = 1

Embedded Element Pattern of Linear Array

Calculate the embedded element pattern of a linear array. Excite the first antenna element in the array. Terminate all the other antenna elements using a 50-ohm resistance.

l = linearArray;
pattern(l, 70e6,'ElementNumber', 1,'Termination', 50);

Directivity Value of Helix Antenna.

Calculate the directivity of a helix antenna.

h = helix;
D = pattern(h, 2e9, 0, 1:1:360);

Showing the first five directivity values.

Dnew = D(1:5)

Dnew = 5×1

   -6.4066
   -6.1929
   -5.9655
   -5.7262
   -5.4770

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.

Radiation Pattern of Dipole Antenna

Plot radiation pattern of dipole antenna in rectangular cartesian co-ordinate system.

pattern(dipole, 70e6:10e6:100e6, 0, 90, 'CoordinateSystem', 'rectangular')

Directivity values of dipole antenna

D = pattern(dipole, 70e6:10e6:100e6, 0, 90, 'CoordinateSystem', 'rectangular')

D = 4×1

  -49.6264
  -50.3098
  -49.1815
  -47.0042

Compare Gain and Realized Gain of Radial Monopole Antenna

Visualize gain plot of radial monopole antenna.

pattern(monopoleRadial,75e6,'Type','gain')

Visualize gain plot of radial monopole antenna.

pattern(monopoleRadial,75e6,'Type','realizedgain')

Input Arguments

object — Antenna or array element

object

Antenna or array element, specified as an object.

frequency — Frequency to calculate or plot antenna or array radiation pattern

scalar | vector

Frequency to calculate or plot the antenna or array radiation pattern, specified as a scalar or a vector with each element in Hz. The vector frequencies support rectangular coordinate system.

Example: 70e6

Data Types: double

azimuth — Azimuth angles and spacing between angles

–180:5:180 (default) | vector

Azimuth angles and spacing between the angles to visualize the radiation pattern, specified as a vector in degrees. If the coordinate system is set to uv, then the U values are specified in this parameter. The values of U are between -1 to 1.

Example: 90

Data Types: double

elevation — Elevation angles and spacing between angles

–90:5:90 (default) | vector

Elevation angles and spacing between the angles to visualize the radiation pattern, specified as a vector in degrees. If the coordinate system is set to uv, then the V values are specified in this parameter. The values of V are between -1 to 1.

Example: 0:1:360

Data Types: double

Name-Value Arguments

Example: 'CoordinateSystem', 'uv'

Specify optional comma-separated pairs of Name,Value pair arguments. Name is the argument name and Value is the corresponding value. Name must appear inside single quotes (''). You can specify several name and value pair arguments in any order as Name1, Value1, ..., NameN, ValueN.

CoordinateSystem — Coordinate system to visualize radiation pattern

'polar' (default) | 'rectangular' | 'uv'

Coordinate system to visualize the radiation pattern, specified as the comma-separated pair consisting of 'CoordinateSystem' and one of these values: 'polar', 'rectangular', 'uv'.

Example: 'CoordinateSystem', 'polar'

Data Types: char

Type — Quantity to plot

'directivity' | 'gain' | 'realizedgain' | 'efield' | 'power' | 'powerdb' | 'phase'

Quantity to plot, specified as a comma-separated pair consisting of 'Type' and one of these values:

• directivity – Directivity in dBi

• gain – Gain in dBi

  Note

  The antenna Gain and Directivity are measured at a distance of 100*lambda.

• realizedgain – Realized gain in dBi

• efield – Electric field in volt/meter

• power – Power in watts

• powerdb – Power in dB

• phase – Phase in degrees.

  Note

  Type can only be set to phase when Polarization is provided.

The default value is 'directivity' for a lossless antenna and 'gain' for a lossy antenna. You cannot plot the 'directivity' of a lossy antenna.

Example: 'Type', 'efield'

Data Types: char

Normalize — Normalize field pattern

true (default) | false | boolean

Normalize field pattern, specified as the comma-separated pair consisting of 'Normalize' and either true or false.

Example: 'Normalize', false

Data Types: logical

PlotStyle — 2-D pattern display style when frequency is vector

'overlay' (default) | 'waterfall'

2-D pattern display style when frequency is a vector, specified as the comma-separated pair consisting of 'PlotStyle' and one of these values:

• 'overlay' – Overlay frequency data in a 2-D line plot

• 'waterfall' – Plot frequency data in a waterfall plot

You can use this property when using pattern function with no output arguments.

Example: 'PlotStyle', 'waterfall'

Data Types: char

Polarization — Field polarization

'H' | 'V' | 'RHCP' | 'LHCP'

Field polarization, specified as the comma-separated pair consisting of 'Polarization' and one of these values:

• 'H' – Horizontal polarization

• 'V' – Vertical polarization

• 'RHCP' – Right-hand circular polarization

• 'LHCP' – Left-hand circular polarization

By default, you can visualize a combined polarization.

Example: 'Polarization', 'RHCP'

Data Types: char

ElementNumber — Antenna element in array

scalar

Antenna element in array, specified as the comma-separated pair consisting of 'ElementNumber' and scalar. This antenna element is connected to the voltage source.

Note

Use this property to calculate the embedded pattern of an array.

Example: 'ElementNumber',1

Data Types: double

Termination — Impedance value for array element termination

50 (default) | scalar

Impedance value for array element termination, specified as the comma-separated pair consisting of 'Termination' and scalar. The impedance value terminates other antenna elements of an array while calculating the embedded pattern of the antenna connected to the voltage source.

Note

Use this property to calculate the embedded pattern of an array.

Example: 'Termination',40

Data Types: double

patternOptions — Parameter to change pattern plot properties

PatternPlotOptions object (default) | scalar

Parameter to change pattern plot properties, specified as the comma-separated pair consisting of 'patternOptions' and a PatternPlotOptions output. The properties that you can vary are:

• Transparency

• SizeRatio

• AntennaOffset

• AntennaVisibility

• MagnitudeScale

Example: p = PatternPlotOptions('Transparency',0.1); Create a pattern plot option with a transparency of 0.1. ant = helix;pattern(ant,2e9,'patternOptions',p); Use this pattern plot option to visualize the pattern of a helix antenna.

Data Types: double

Output Arguments

pat — Radiation pattern of antenna or array or embedded pattern of array

matrix

Radiation pattern of antenna or array or embedded pattern of array, returned as a matrix of number of elevation values by number of azimuth values. The pattern is one of the following:

• directivity – Directivity in dBi (lossless antenna or array)

• gain – Gain in dBi (lossy antenna or array)

• realizedgain – Realized gain in dBi (lossy antenna or array)

• efield – Electric field in volt/meter

• power – Power in watts

• powerdb – Power in dB

Matrix size is number of elevation values multiplied by number of azimuth values.

azimuth — Azimuth angles of calculated radiation pattern

vector in degrees

Azimuth angles to calculate the radiation pattern, returned as a vector in degrees.

elevation — Elevation angles of calculate radiation pattern

vector in degrees

Elevation angles to calculate the radiation pattern, returned as a vector in degrees.

References

[1] Makarov, Sergey N. Antenna and EM Modeling in MATLAB. Chapter3, Sec 3.4 3.8. Wiley Inter-Science.

[2] Balanis, C.A. Antenna Theory, Analysis and Design, Chapter 2, sec 2.3-2.6, Wiley.