circularArray

Create circular antenna array

Description

The circularArray object creates a circular antenna array. Circular array finds application in direction of arrival (DoA) systems. You can use circular arrays to perform 2-D scanning, while lowering element counts. These arrays also have the ability for 360-degree scanning. The individual elements in the circular array are part of the same array environment. This property reduces the impact of edge effects and other coupling variation.

Creation

Syntax

array = circularArray

array = circularArray(PropertyName=Value)

Description

array = circularArray creates a circular antenna array in the xy-plane.

array = circularArray(PropertyName=Value) sets properties using one or more name–value arguments. PropertyName is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as PropertyName1=Value1,...,PropertyNameN=ValueN. Properties that you do not specify, retain their default values.

For example, array = circularArray(Element=monopole,NumElements=8) creates a circular array of 8 monopole antennas.

Properties

Element — Individual antenna type in array

dipole (default) | antenna object | vector of antenna objects | custom antenna object | measuredAntenna object | vector of custom antenna objects

Individual antenna type, specified as a single antenna object for homogeneous array or a vector of antenna objects of same type with varying dimensions and load for heterogeneous array. The element can be:

• an object from the Antenna Catalog

  Note

  Following catalog antennas are not supported as an element:

  • cavity, cavityCircular

  • slot, vivaldiAntipodal

  • Antennas with tilted ground planes.

  • All reflector antennas except reflector with a dipole exciter.

• an antenna without a substrate created using customAntennaGeometry, customAntennaMesh, customAntennaStl, or customAntenna objects

• a single port measuredAntenna object

  Note

  Using measuredAntenna as an array element has following limitations:

  • Only analysis using the patternMultiply function is supported, and only at the frequencies specified in the FieldFrequency property of the measuredAntenna object.

  • Linear array with measuredAntenna as an element is not supported as an exciter for the backing structures, parabolic antennas, platform-installed antennas, and plane-wave excitation environment.

Example: dipole

Example: [monopole monopole(Height=2)]

Example: customAntenna

Example: measuredAntenna

NumElements — Number of elements in array

6 (default) | positive scalar integer

Number of elements in the array,specified as a positive scalar integer. The elements in the array are arranged along the x-axis.

Example: 4

Data Types: double

Radius — Radius of array

1 (default) | positive scalar integer

Radius of array, specified as a positive scalar integer in meters.

Example: 0.4

Data Types: double

AngleOffset — Starting angle offset for first element in array

0 (default) | real scalar

Starting angle offset for first element in array, specified as a real scalar in degrees.

Example: 8

Data Types: double

AmplitudeTaper — Excitation amplitude for antenna elements in array

1 (default) | real positive vector of size 'Element'

Excitation amplitude for antenna elements in the array, specified as a real positive vector of size 'Element'.

Example: [0 1]

Data Types: double

PhaseShift — Phase shift for each element in array

0 (default) | real vector of size 'Element' in degrees

Phase shift for each element in the array, specified as a real vector of size 'Element' in degrees.

Example: [0 2]

Data Types: double

Tilt — Tilt angle of array

0 (default) | numeric scalar | numeric vector

Tilt angle of the array in degrees, specified as a scalar or vector. For more information, see Rotate Antennas and Arrays.

Example: 90

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

Data Types: double

TiltAxis — Tilt axis of array

[1 0 0] (default) | three-element vector | 2-by-3 matrix | "X" | "Y" | "Z"

Tilt axis of the array, specified as one of these values:

• 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, specified as a 2-by-3 matrix corresponding to two three-element vectors of Cartesian coordinates. In this case, the array rotates around the line joining the two points.

• "x", "y", or "z" to describe a rotation about the x-, y-, or z-axis, respectively.

For more information, see Rotate Antennas and Arrays.

Example: [0 1 0]

Example: [0 0 0;0 1 0]

Example: "Z"

Data Types: double | string

Object Functions

arrayFactor	Array factor in dB
axialRatio	Calculate and plot axial ratio of antenna or array
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
correlation	Correlation coefficient between two antennas in array
current	Current distribution on antenna or array surface
design	Create antenna, array, or AI-based antenna resonating at specified frequency
efficiency	Calculate and plot radiation efficiency of antenna or array
EHfields	Electric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
feedCurrent	Calculate current at feed for antenna or array
impedance	Calculate and plot input impedance of antenna or scan impedance of array
info	Display information about antenna, array, or platform
layout	Display array or PCB stack layout
memoryEstimate	Estimate memory required to solve antenna or array mesh
mesh	Generate and view mesh for antennas, arrays, and custom shapes
meshconfig	Change meshing mode of antenna, array, custom antenna, custom array, or custom geometry
msiwrite	Write antenna or array analysis data to MSI planet file
optimize	Optimize antenna and array catalog elements using SADEA or TR-SADEA algorithm
pattern	Plot radiation pattern of antenna, array, or embedded element of array
patternAzimuth	Azimuth plane radiation pattern of antenna or array
patternElevation	Elevation plane radiation pattern of antenna or array
patternMultiply	Radiation pattern of array using pattern multiplication
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
phaseShift	Calculate phase shift values for arrays or multi-feed PCB stack
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array, AI-based antenna, platform, or shape
sparameters	Calculate S-parameters for antenna or array
stlwrite	Write mesh information to STL file
vswr	Calculate and plot voltage standing wave ratio (VSWR) of antenna or array element

Examples

Plot Elevation Pattern of Circular Antenna Array

Create a circular antenna array using 10 antenna elements. View the layout of the antenna elements in the array.

ca = circularArray(NumElements=10)

ca = 
  circularArray with properties:

           Element: [1×1 dipole]
       NumElements: 10
            Radius: 1
       AngleOffset: 0
    AmplitudeTaper: 1
        PhaseShift: 0
              Tilt: 0
          TiltAxis: [1 0 0]

figure
layout(ca)

View the array.

figure
show(ca)

Plot the elevation pattern of the circular array at a frequency of 70 MHz.

figure
patternElevation(ca,70e6)

Perform Pattern Multiplication for Circular Array Using Measured Element Pattern Data

Load the measured E-field data. Define the field frequency, azimuth and elevation angles.

load("mesAnt_circ_array.mat")
freq = 3e9;
az = -180:5:180;
el = -90:5:90;

Create measuredAntenna object and set its properties using the defined parameters.

mesAnt = measuredAntenna(E=Efield,Direction=Dir,NumPorts=1, ...
    Azimuth=az,Elevation=el,FieldCoordinate="rectangular", ...
    FieldFrequency=freq)

mesAnt = 
  measuredAntenna with properties:

                  E: [2701×3 double]
        Directivity: []
          Direction: [2701×3 double]
        PhaseCenter: [0 0 0.0750]
           NumPorts: 1
     FieldFrequency: 3.0000e+09
    FieldCoordinate: "rectangular"
            Azimuth: [-180 -175 -170 -165 -160 -155 -150 -145 -140 -135 -130 -125 -120 -115 -110 -105 -100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 … ] (1×73 double)
          Elevation: [-90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90]
        Sparameters: []

Create a six-element circular array with 0.0732 m radius and use the measuredAntenna object as its element.

circArr = circularArray(Element=mesAnt,Radius=0.0732)

circArr = 
  circularArray with properties:

           Element: [1×1 measuredAntenna]
       NumElements: 6
            Radius: 0.0732
       AngleOffset: 0
    AmplitudeTaper: 1
        PhaseShift: 0
              Tilt: 0
          TiltAxis: [1 0 0]

Perform pattern multiplication and plot the resultant array E-field pattern.

figure 
patternMultiply(circArr,freq,Type="efield")

Version History

Introduced in R2016b

R2026a: Added support for pattern multiplication using measured or simulated radiation pattern data

You can now use the measuredAntenna object containing measured or simulated pattern data as an element in linear arrays. Assign the object to the Element property of the circularArray object and use the patternMultiply function to compute and visualize the overall radiation pattern of the array.