vivaldiOffsetCavity

Create Vivaldi antenna with rectangular or circular offset cavity

Since R2021a

Description

The default vivaldiOffsetCavity object creates a Vivaldi antenna with a rectangular or circular offset cavity on an exponential or linear taper ground plane resonating around 16 GHz. 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.

Creation

Syntax

vi = vivaldiOffsetCavity

vi = vivaldiOffsetCavity(Name=Value)

Description

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

vi = vivaldiOffsetCavity(Name=Value) sets properties using one or more name-value arguments. Name is the property name and Value is the corresponding value. You can specify several name-value arguments in any order as Name1=Value1,...,NameN=ValueN. Properties that you do not specify, retain their default values.

For example, ant = vivaldiOffsetCavity(CavityShape="Circular") creates a Vivaldi antenna with a circular offset cavity.

Properties

TaperLength — Taper length measured from cross taper end point

0.105 (default) | positive scalar

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

Example: 200e-3

ApertureWidth — Aperture width

0.02 (default) | positive scalar

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

Example: 3e-3

OpeningRate — Taper opening rate

25 (default) | positive scalar

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: 0.3

Data Types: double

TaperedSlotWidth — Width of tapered end

0.002 (default) | positive scalar

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

Example: 0.003

Data Types: double

CrossTaperLength — Length of cross taper

0.0131 (default) | positive scalar

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

Example: 2

Data Types: double

TaperOffset — Signed distance from mid-TaperedSlotWidth along y-axis

-0.0063 (default) | real-valued scalar

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

Example: 0.03

Data Types: double

SlotLineWidth — Width of slot line

5e-04 (default) | scalar

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

Example: 0.0002

Data Types: double

CavityToTaperSpacing — Transition distance from cavity to cross taper

0.0107 (default) | positive scalar

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

Example: 0.003

Data Types: double

CavityShape — Shape of cavity

"Rectangular" (default) | "Circular"

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

Example: "Circular"

Data Types: string

CavityOffset — Distance from feed point of antenna along x and y direction

[0.0048 0.0030] (default) | two-element positive vector

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: [0.01 0.01]

Data Types: double

GroundPlaneLength — Ground plane length

0.1400 (default) | positive scalar

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

Example: 2

Data Types: double

GroundPlaneWidth — Ground plane width

0.0240 (default) | positive scalar

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

Example: 4

Data Types: double

FeedOffset — Signed distance from line of symmetry of GroundPlaneWidth to feed point

-0.0030 (default) | real-valued scalar

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

Example: 0.001

Data Types: double

Conductor — Type of metal material

'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, 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 — 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

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. 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

CavityDiameter — Circular cavity diameter

0.0100 (default) | positive scalar

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

Example: 0.05

Data Types: double

Rectangular Cavity

CavityLength — Length of rectangular cavity

0.0073 (default) | positive scalar

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

Example: 0.003

Data Types: double

CavityWidth — Width of rectangular cavity

0.0066 (default) | positive scalar

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

Example: 0.002

Data Types: double

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	Design prototype antenna or arrays for resonance around specified frequency or create AI-based antenna from antenna catalog objects
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	Mesh properties of metal, dielectric antenna, or array structure
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 or array using SADEA optimizer
pattern	Plot radiation pattern and phase of antenna or array or embedded pattern of antenna element in 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

Create Default Vivaldi Antenna with Offset Cavity and Plot its Radiation Pattern

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)

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

pattern(ant,18e9)

Create Vivaldi Antenna with Offset Cavity and Plot its Radiation Pattern

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)

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

pattern(ant,16e9)

Create Vivaldi Antenna with Circular Cavity and Plot its Return Loss

Create and visualize a Vivaldi antenna with a circular cavity.

ant = vivaldiOffsetCavity(CavityShape="Circular");
show(ant)

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

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

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

Version History

Introduced in R2021a