cavityCircular

Create circular cavity-backed antenna

Description

The default cavityCircular object creates a circular cavity-backed antenna resonating around 833 MHz. By default, a dipole element is used as an exciter for this antenna. The feed point is located on the exciter.

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Creation

Syntax

c = cavityCircular

c = cavityCircular(PropertyName=Value)

Description

c = cavityCircular creates a circular cavity-backed antenna with default property values. The default dimensions are chosen for an operating frequency of around 833 MHz.

c = cavityCircular(PropertyName=Value) creates a circular cavity-backed antenna, with properties specified by 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 not specified retain their default values.

For example, c = cavityCircular(Radius=0.2) creates a circular-cavity backed antenna with cavity radius of 0.2 m. and default values for other properties.

Properties

Radius — Cavity radius

0.1 (default) | positive scalar

Cavity radius, specified as a positive scalar in meters.

Example: 0.2

Data Types: double

Height — Cavity height along z-axis

0.075 (default) | positive scalar

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

Example: 0.001

Data Types: double

Exciter — Exciter antenna or array type

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 object from the antenna catalog or an array object from array catalog as an exciter. To create the cavity backing structure without an exciter, specify this property as an empty array.

Example: Exciter=horn

Example: Exciter=linearArray(Element=patchMicrostrip)

Example: Exciter=[]

Spacing — Distance between exciter and base of cavity

0.075 (default) | positive scalar

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

Example: 10e-2

Data Types: double

Substrate — Type of dielectric material

dielectric("Air") (default) | dielectric object

Type of dielectric material used as a substrate, specified as a dielectric object. You can choose any dielectric material from the DielectricCatalog or specify a dielectric material of your choice. You can also specify multiple dielectric layers. When creating multiple dielectric layers, specify the name, thickness, loss tangent, and relative permittivity of each layer. The substrate dimensions must be equal to the ground plane dimensions. For more information on dielectric substrate meshing, see Meshing.

Example: dielectric("FR4")

Example: dielectric(Name={"FR4","Teflon"},Thickness=[0.5 0.5],LossTangent=[0.002 0.002],EpsilonR=[4.8 2.1])

Conductor — Type of metal

metal("PEC") (default) | metal object

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

Example: metal("Copper")

Load — Lumped elements

[1x1 lumpedElement] (default) | lumpedElement object

Lumped elements added to the antenna feed, specified as a lumpedElement object. You can add a load anywhere on the surface of the antenna. By default, the load is at the feed.

Example: lumpedElement(Impedance=75)

EnableProbeFeed — Option to create probe feed from backing structure to exciter

0 (default) | 1

Option to create probe feed from backing structure to exciter, specified as a numeric 0 or 1. Specify 0 to disable or 1 to enable the probe feed. By default, probe feed is disabled.

Example: 1

Data Types: double

Tilt — Tilt angle of antenna

0 (default) | scalar | vector

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

TiltAxis — Tilt axis of antenna

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

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

axialRatio	Calculate and plot axial ratio of antenna or array
bandwidth	Calculate and plot absolute bandwidth of antenna or array
beamwidth	Beamwidth of antenna
charge	Charge distribution on antenna or array surface
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
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
peakRadiation	Calculate and mark maximum radiation points of antenna or array on radiation pattern
rcs	Calculate and plot monostatic and bistatic radar cross section (RCS) of platform, antenna, or array
resonantFrequency	Calculate and plot resonant frequency of antenna
returnLoss	Calculate and plot return loss of antenna or scan return loss of array
show	Display antenna, array structures, shapes, or platform
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

Circular Cavity-Backed Antenna

Create and view a default circular cavity-backed antenna.

a = cavityCircular

a = 
  cavityCircular with properties:

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

   0.0023 - 0.0005i   0.0029 + 0.0007i

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

Version History

Introduced in R2017b