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.

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Creation

Syntax

circularcavity = cavityCircular

circularcavity = cavityCircular(Name=Value)

Description

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.

Properties

Exciter — Antenna or array to use as exciter

dipole (default) | antenna object | array object | empty array

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 — Cavity radius

0.1000 (default) | scalar

Radius of cavity, specified as a scalar in meters.

Example: 0.2

Data Types: double

Height — Cavity height along z-axis

0.0750 (default) | scalar

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

Example: 0.001

Data Types: double

Spacing — Distance between exciter and base of cavity

0.0750 (default) | scalar

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

Example: 7.5e-2

Data Types: double

Substrate — Type of dielectric material

"Air" (default) | dielectric object

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")

EnableProbeFeed — Create probe feed from backing structure to exciter

0 (default) | 1

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

Conductor — Type of metal material

"PEC" (default) | metal object

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")

Load — Lumped elements

[1x1 lumpedElement] (default) | lumped element object

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

Example: 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: 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: TiltAxis = 'Z'

Data Types: double

Object Functions

show	Display antenna, array structures or shapes
axialRatio	Axial ratio of antenna
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
current	Current distribution on antenna or array surface
design	Design prototype antenna or arrays for resonance around specified frequency
efficiency	Radiation efficiency of antenna
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, 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
rcs	Calculate and plot radar cross section (RCS) of platform, antenna, or array
returnLoss	Return loss of antenna; scan return loss of array
sparameters	Calculate S-parameter for antenna and antenna array objects
vswr	Voltage standing wave ratio of antenna

Examples

Circular Cavity-Backed Antenna

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)

Circular Cavity-Backed Equiangular Spiral

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 Circular Cavity-Backed Linear Array

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 Cylindrical Dielectric Resonator Antenna with Circular Cavity Backing Structure

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)

Analyze Circular Cavity Structure in Conformal Array

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

   0.0024 - 0.0005i   0.0029 + 0.0007i

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

Version History

Introduced in R2017b