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cavity

Create cavity-backed antenna

Description

The cavity object is a cavity-backed antenna located on the X-Y-Z plane. The default cavity antenna has a dipole as an exciter. The feed point is on the exciter.

Creation

Syntax

c = cavity
c = cavity(Name,Value)

Description

c = cavity creates a cavity backed antenna located on the X-Y-Z plane. By default, the dimensions are chosen for an operating frequency of 1 GHz.

example

c = cavity(Name,Value) creates a cavity-backed antenna, with additional properties specified by one or more name–value pair arguments. Name is the property name and Value is the corresponding value. You can specify several name-value pair arguments in any order as Name1, Value1, ..., NameN, ValueN. Properties not specified retain their default values.

Properties

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

Example: 'Exciter',dipole

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

Note

The substrate dimensions must be equal to the groundplane dimensions.

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

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

Length of the rectangular cavity along the x-axis, specified as a scalar in meters.

Example: 'Length',30e-2

Data Types: double

Width of the rectangular cavity along the y-axis, specified as a scalar in meters.

Example: 'Width',25e-2

Data Types: double

Height of the rectangular cavity along the z-axis, specified as a scalar in meters.

Example: 'Height',7.5e-2

Data Types: double

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

Example: 'Spacing',7.5e-2

Data Types: double

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.

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

Example: 'EnableProbeFeed',1

Data Types: double

Tilt angle of antenna, specified as a scalar or vector with each element unit in degrees.

Example: 'Tilt',90

Example: 'Tilt',[90 90 0]

Data Types: double

Tilt axis of the antenna, specified as:

  • A three-element vector 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 as three-element vectors of Cartesian coordinates. In this case, the antenna rotates along the line joining the two points.

  • A string input for simple rotations around the principal planes, X, Y, or Z.

For more information see, Rotate Antenna and Arrays

Example: 'TiltAxis',[0 1 0]

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

Example: 'TiltAxis','Z'

Data Types: double

Object Functions

showDisplay antenna or array structure; Display shape as filled patch
infoDisplay information about antenna or array
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 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 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

Examples

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Create and view a cavity-backed dipole antenna with 30cm length, 25cm width, 7.5cm height and spaced 7.5cm from the bowtie for operation at 1GHz.

c = cavity('Length',30e-2, 'Width',25e-2,'Height',7.5e-2,'Spacing',7.5e-2);
show(c)

Create a cavity-backed antenna using a dielectric substrate 'FR4'.

d = dielectric('FR4');
c = cavity('Length',30e-2,'Width',25e-2,'Height',20.5e-3,'Spacing',7.5e-3,...
    'Substrate',d)
show(c)
c = 

  cavity with properties:

      Exciter: [1x1 dipole]
    Substrate: [1x1 dielectric]
       Length: 0.3000
        Width: 0.2500
       Height: 0.0205
      Spacing: 0.0075
         Tilt: 0
     TiltAxis: [1 0 0]

Plot the radiation pattern of the antenna at a frequency of 1 GHz.

figure
pattern(c,1e9)

References

[1] Balanis, C.A.Antenna Theory: Analysis and Design.3rd Ed. New York: Wiley, 2005.

Introduced in R2015a

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