Create circular cavity-backed antenna


Use the circularCavity object to create a circular cavity-backed antenna. By default, the exciter used is a dipole. The dimensions are chosen for an operating frequency of 1 GHz.

Default view of a circular cavity-backed antenna explaining the various parameters.




circularcavity = cavityCircular creates a circular cavity-backed antenna.


circularcavity = cavityCircular(Name,Value) sets properties using one or more name-value pairs. For example, circularcavity = cavityCircular('Radius',0.2) creates a circular cavity of radius 0.2 m. Enclose each property name in quotes.


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Antenna type used as an exciter, specified as an object. Except for reflector and cavity antenna elements, you can use any of the single elements in the Antenna Toolbox™ as an exciter.

Example: 'Exciter',monopole

Example: circularcavity.Exciter = monopole

Data Types: char | string

Radius of cavity, specified as a scalar in meters.

Example: 'Radius',0.2

Example: circularcavity.Radius = 0.2

Data Types: double

Cavity height along z-axis, specified as a scalar in meters.

Example: 'Height',0.001

Example: circularcavity.Height = 0.001

Data Types: double

Distance between the exciter and the base of the cavity, specified a scalar in meters.

Example: 'Spacing',7.5e-2

Example: circularcavity.Spacing = 7.5e-2

Data Types: double

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


The substrate dimensions must be equal to the groundplane dimensions.

Example: d = dielectric('FR4'); 'Substrate',d

Example: d = dielectric('FR4'); circularcavity.Substrate = d

Create probe feed from backing structure to exciter, specified as 0 or 1 or a positive scalar. By default, probe feed is not enabled.

Example: 'EnableProbeFeed',1

Example: circularcavity.EnableProbeFeed = 1

Data Types: double | logical

Lumped elements added to the antenna feed, specified as a lumped element object handle. For more information, see lumpedElement.

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

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

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 vectors.


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

Data Types: double

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.

Example: 'TiltAxis',[0 1 0]

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

Example: ant.TiltAxis = 'Z'


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

Object Functions

showDisplay antenna or array structure; display shape as filled patch
axialRatioAxial ratio of antenna
beamwidthBeamwidth of antenna
chargeCharge distribution on metal or dielectric antenna or array surface
currentCurrent distribution on metal or dielectric antenna or array surface
designDesign prototype antenna or arrays for resonance at specified frequency
EHfieldsElectric and magnetic fields of antennas; Embedded electric and magnetic fields of antenna element in arrays
impedanceInput impedance of antenna; scan impedance of array
meshMesh properties of metal or dielectric antenna or array structure
meshconfigChange mesh mode of antenna structure
patternRadiation pattern and phase of antenna or array; Embedded pattern of antenna element in array
patternAzimuthAzimuth pattern of antenna or array
patternElevationElevation pattern of antenna or array
returnLossReturn loss of antenna; scan return loss of array
sparametersS-parameter object
vswrVoltage standing wave ratio of antenna


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Create and view a default circular cavity-backed antenna.

a = cavityCircular
a = 
  cavityCircular with properties:

            Exciter: [1x1 dipole]
          Substrate: [1x1 dielectric]
             Radius: 0.1000
             Height: 0.0750
            Spacing: 0.0750
    EnableProbeFeed: 0
               Tilt: 0
           TiltAxis: [1 0 0]
               Load: [1x1 lumpedElement]


Create and view an equiangular spiral backed by a circular cavity. The cavity dimensions are:

Radius = 0.02 m

Height = 0.01 m

Spacing = 0.01 m

 ant = cavityCircular('Exciter',spiralEquiangular,'Radius',0.02,   ...
          'Height',0.01,'Spacing', 0.01);

Introduced in R2017b