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vivaldiOffsetCavity

Create Vivaldi antenna with rectangular or circular offset cavity

    Description

    The vivaldiOffsetCavity object creates a Vivaldi antenna with a rectangular or circular offset cavity on an exponential or linear taper ground plane. The Vivaldi offset cavity antenna has a metal structure which helps the antenna avoid the shortcomings of an antipodal Vivaldi antenna like large microstrip loss, complex installation, and integration. The wideband characteristics of a Vivaldi offset cavity antenna make it suitable for ultra-wideband phased array applications used in aviation and aerospace technologies.

    Offset cavity Vivaldi antenna geometry, default radiation pattern, and impedance plot.

    Creation

    Description

    example

    vi = vivaldiOffsetCavity creates a default Vivaldi antenna with a rectangular offset cavity on an exponential taper ground plane. By default, the antenna operates at a frequency range of 16–21 GHz and is located in the xy- plane.

    example

    vi = vivaldiOffsetCavity(Name,Value) sets Properties using one or more name-value pairs. For example, ant = vivaldiOffsetCavity('CavityShape','Circular') creates a Vivaldi antenna with a circular offset cavity.

    Properties

    expand all

    Taper length measured from the cross taper end point, specified as a positive scalar in meters.

    Example: 'TaperLength',200e-3

    Aperture width of the Vivaldi antenna, specified as a positive scalar in meters.

    Example: 'ApertureWidth',3e-3

    Taper opening rate measured from cross taper end point, specified as a positive scalar. This property determines the rate at which the notch transitions from the TaperedSlotWidth to the aperture. When OpeningRate is 0, the notch has a linear profile creating a linear tapered slot. For other values, it has other values it has an exponential profile.

    Example: 'OpeningRate',0.3

    Data Types: double

    Width of the tapered end, specified as a positive scalar in meters.

    Example: 'TaperedSlotWidth',0.003

    Data Types: double

    Length of the cross taper, specified as a positive scalar in meters.

    Example: 'CrossTaperLength',2

    Data Types: double

    Signed distance from mid-TaperedSlotWidth along the y-axis, specified as a real-valued scalar in meters.

    Example: 'TaperOffset',0.03

    Data Types: double

    Width of the slot line, specified as a scalar in meters.

    Example: 'SlotLineWidth',0.0002

    Data Types: double

    Transition distance from the cavity to the cross taper, specified as a scalar in meters.

    Example: 'CavityToTaperSpacing',0.003

    Data Types: double

    Shape of the cavity, specified as a character array. The dimensions of cavity can be modified using Circular Cavity and Rectangular Cavity properties.

    Example: 'CavityShape','Circular'

    Data Types: char

    Distance from the feed point of the antenna along X and Y direction, specified as a two-element vector in meters. The first element of the vector is the distance from the feed point to the left edge of the cavity along the x-axis. The second element of the vector is the distance from the feed point to the bottom edge of the cavity along the y-axis.

    Example: 'CavityOffset',[0.01 0.01]

    Data Types: double

    Ground plane length, specified as a positive scalar in meters. By default, the ground plane length is measured along the x-axis.

    Example: 'GroundPlaneLength',2

    Data Types: double

    Ground plane width, specified as a positive scalar in meters. By default, ground plane width is measured along the y-axis.

    Example: 'GroundPlaneWidth',4

    Data Types: double

    Signed distance from the line of symmetry of the GroundPlaneWidth to the feed point, specified as a real-valued scalar in meters.

    Example: 'FeedOffset',0.001

    Data Types: double

    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, see metal. For more information on metal conductor meshing, see Meshing.

    Example: m = metal('Copper'); 'Conductor',m

    Example: m = metal('Copper'); ant.Conductor = m

    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 the vectors.

    Data Types: double

    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: ant.TiltAxis = 'Z'

    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. For more information, see lumpedElement.

    Example: 'Load',lumpedelement, where lumpedelement is the load added to the antenna feed.

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

    Circular Cavity

    Circular cavity diameter, specified as a positive scalar in meters. This property is visible if CavityShape is set 'Circular'.

    Example: 'CavityDiameter',0.05

    Data Types: double

    Rectangular Cavity

    Length of the rectangular cavity, specified as a positive scalar in meters. This property is visible if CavityShape is set 'Rectangular'.

    Example: 'CavityLength',0.003

    Data Types: double

    Width of the rectangular cavity, specified as a positive scalar in meters. This property is visible if CavityShape is set 'Rectangular'.

    Example: 'CavityWidth',0.002

    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 or arrays for resonance around specified frequency
    efficiencyRadiation efficiency of antenna
    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
    optimizeOptimize antenna or array using SADEA optimizer
    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
    rcsCalculate and plot radar cross section (RCS) of platform, antenna, or array
    returnLossReturn loss of antenna; scan return loss of array
    sparametersCalculate S-parameter for antenna and antenna array objects
    vswrVoltage standing wave ratio of antenna

    Examples

    collapse all

    Create a default Vivaldi antenna with an offset cavity.

    ant = vivaldiOffsetCavity
    ant = 
      vivaldiOffsetCavity with properties:
    
                 TaperLength: 0.1050
               ApertureWidth: 0.0200
                 OpeningRate: 25
            TaperedSlotWidth: 0.0020
            CrossTaperLength: 0.0131
                 TaperOffset: -0.0063
               SlotLineWidth: 5.0000e-04
        CavityToTaperSpacing: 0.0107
                 CavityShape: 'Rectangular'
                CavityLength: 0.0073
                 CavityWidth: 0.0066
                CavityOffset: [0.0048 0.0030]
           GroundPlaneLength: 0.1400
            GroundPlaneWidth: 0.0240
                  FeedOffset: -0.0030
                   Conductor: [1x1 metal]
                        Tilt: 0
                    TiltAxis: [1 0 0]
                        Load: [1x1 lumpedElement]
    
    

    View the antenna using show function.

    show(ant)

    Figure contains an axes object. The axes object with title vivaldiOffsetCavity antenna element contains 3 objects of type patch, surface. These objects represent PEC, feed.

    Plot the radiation pattern of the antenna at a frequency of 18 GHz.

    pattern(ant,18e9)

    Figure contains an axes object and other objects of type uicontrol. The axes object contains 3 objects of type patch, surface.

    Create Vivaldi antenna with offset rectangular cavity.

    ant = vivaldiOffsetCavity('CavityOffset',[0.006 0.003])
    ant = 
      vivaldiOffsetCavity with properties:
    
                 TaperLength: 0.1050
               ApertureWidth: 0.0200
                 OpeningRate: 25
            TaperedSlotWidth: 0.0020
            CrossTaperLength: 0.0131
                 TaperOffset: -0.0063
               SlotLineWidth: 5.0000e-04
        CavityToTaperSpacing: 0.0107
                 CavityShape: 'Rectangular'
                CavityLength: 0.0073
                 CavityWidth: 0.0066
                CavityOffset: [0.0060 0.0030]
           GroundPlaneLength: 0.1400
            GroundPlaneWidth: 0.0240
                  FeedOffset: -0.0030
                   Conductor: [1x1 metal]
                        Tilt: 0
                    TiltAxis: [1 0 0]
                        Load: [1x1 lumpedElement]
    
    

    View the antenna using show function.

    show(ant)

    Figure contains an axes object. The axes object with title vivaldiOffsetCavity antenna element contains 3 objects of type patch, surface. These objects represent PEC, feed.

    Plot radiation pattern of the antenna at a frequency of 16 GHz.

    pattern(ant,16e9)

    Figure contains an axes object and other objects of type uicontrol. The axes object contains 3 objects of type patch, surface.

    Create and visualize a Vivaldi antenna with a circular cavity.

    ant = vivaldiOffsetCavity('CavityShape','Circular');
    show(ant)

    Figure contains an axes object. The axes object with title vivaldiOffsetCavity antenna element contains 3 objects of type patch, surface. These objects represent PEC, feed.

    Plot the return loss of the antenna over a frequency range of 15 GHz-20 GHz.

    returnLoss(ant,linspace(15e9,21e9,41))

    Figure contains an axes object. The axes object with title Return Loss contains an object of type line.

    References

    [1] X. Ma, S. Chai, K. Xiao and L. Ding. "Design of All-Metal Vivaldi Phased Array Antenna," IEEE 3rd International Conference on Signal and Image Processing (ICSIP), 2018, pp. 547-551, doi: 10.1109/SIPROCESS.2018.8600487.

    [2] C. L. Prasanna, M. Bhagya Lakshmi, and N. N. Sastry. "A Parametric Analysis & Design of All Metal Vivaldi Antenna Covering 3.0-18 GHz for DF and Phased Array Applications," Progress In Electromagnetics Research C, vol. 92 (April 2019): pp. 57-69. doi:10.2528/PIERC19020601

    Introduced in R2021a