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cavityCircular

Create circular cavity-backed antenna

Description

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.

Creation

Description

example

circularcavity = cavityCircular creates a circular cavity-backed antenna.

example

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.

Properties

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Exciter antenna or array type, specified as a single-element antenna object, an array object, or an empty array. Except for reflector and cavity antenna elements, you can use any Antenna Toolbox™ antenna or array element as an exciter. To create the cavity backing structure without the exciter, specify this property as an empty array.

Example: horn

Example: linearArray(Element=patchMicrostrip)

Example: []

Radius of cavity, specified as a scalar in meters.

Example: 0.2

Data Types: double

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

Example: 0.001

Data Types: double

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

Example: 7.5e-2

Data Types: double

Type of dielectric material used as a substrate, specified as a 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 ground plane dimensions.

Example: dielectric("FR4")

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: 1

Data Types: logical

Type of the metal used as a conductor, specified as a metal material object. You can choose any metal from the MetalCatalog or specify a metal of your choice. For more information, see metal. For more information on metal conductor meshing, see Meshing.

Example: metal("Copper")

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

Example: lumpedElement(Impedance=75)

Tilt angle of the antenna 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 antenna at 90 degrees about the two axes defined by the vectors.

Data Types: double

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

  • 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, specified as a 2-by-3 matrix corresponding to two three-element vectors of Cartesian coordinates. In this case, the antenna 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

axialRatioCalculate and/or plot axial ratio of antenna or array
bandwidthCalculate and/or plot absolute bandwidth of antenna
beamwidthBeamwidth of antenna
chargeCharge distribution on antenna or array surface
currentCurrent distribution on antenna or array surface
designDesign prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
efficiencyRadiation efficiency of antenna
EHfieldsElectric and magnetic fields of antennas or embedded electric and magnetic fields of antenna element in arrays
impedanceInput impedance of antenna or scan impedance of array
infoDisplay information about antenna, array, or platform
memoryEstimateEstimate memory required to solve antenna or array mesh
meshMesh properties of metal, dielectric antenna, or array structure
meshconfigChange meshing mode of antenna, array, custom antenna, custom array, or custom geometry
optimizeOptimize antenna or array using SADEA optimizer
patternPlot radiation pattern and phase of antenna or array or embedded pattern of antenna element in array
patternAzimuthAzimuth plane radiation pattern of antenna or array
patternElevationElevation plane radiation pattern of antenna or array
rcsCalculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequencyCalculate and/or plot resonant frequency of antenna
returnLossReturn loss of antenna or scan return loss of array
showDisplay antenna, array structures, shapes, or platform
sparametersCalculate S-parameters for antennas and antenna arrays
vswrVoltage standing wave ratio (VSWR) of antenna or array element

Examples

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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
          Conductor: [1x1 metal]
               Tilt: 0
           TiltAxis: [1 0 0]
               Load: [1x1 lumpedElement]

show(a)

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);
 show(ant)     

Create a linear array of H-shaped patch microstrip antenna.

arr = linearArray(Element=patchMicrostripHnotch,ElementSpacing=0.04);

Create a circular cavity-backed antenna with linear array exciter.

ant = cavityCircular(Exciter=arr)
ant = 
  cavityCircular with properties:

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

show(ant)

Create and visualize a circular cavity-backed cylindrical dielectric resonator antenna.

e = draCylindrical;
ant = cavityCircular(Exciter=e)
ant = 
  cavityCircular with properties:

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

show(ant)

This example shows how to create a circular cavity structure as an element in a conformalArray and plot its surface current distribution.

Create Circular Cavity Antenna

Create a circular cavity antenna operating at 1 GHz using the design function and the cavityCircular element from the antenna catalog. Display the antenna.

f = 1e9;
lambda = 3e8/f;
ant = design(cavityCircular,f);
figure
show(ant)

Derive Backing Structure

Derive the circular cavity backing structure from the cavity antenna by specifying the 'Exciter' property as an empty array. Display the backing structure.

ant.Exciter = [];
figure
show(ant)

Create Conformal Array

Create and display a conformal array with circular cavity as one of its elements.

ca = conformalArray;
ca.Reference = "origin";
ca.ElementPosition = [0 0 0; 0 0 0.25; 0 0 0.5];
ca.Element = {ca.Element{1} ant ca.Element{2}};
figure
show(ca)

Plot Surface Current Distribution

Calculate the current at the feed location and plot the surface current distribution of the conformal array at 1 GHz.

If = feedCurrent(ca,f)
If = 1×2 complex

   0.0023 - 0.0005i   0.0029 + 0.0007i

figure
current(ca,f,Scale="log10")

Version History

Introduced in R2017b