Main Content

spiralRectangular

Create rectangular spiral antenna on X-Y plane

Description

The spiralRectangular object creates a single or two-arm rectangular spiral antenna. The default rectangular spiral has two arms, is center-fed and is on the X-Y plane. The default resonating frequency is 7.65 GHz.

A spiral rectangular antenna is made up of filaments. The distance between the two violet dashed lines in the diagram represents the first filament or the initial width. The distance between the two orange dashed lines in the diagram represents the second filament or the initial length.

Default view of a rectangular spiral antenna showing the antenna parameters and the feed location.

Creation

Description

example

ant = spiralRectangular creates a default rectangular spiral antenna object operating at 7.65 GHz.

ant = spiralRectangular(Name,Value) sets properties using one or more name-value pairs. For example, ant = spiralRectangular('NumArms',1) creates a rectangular spiral antenna object with one arm. Enclose each property name in quotes.

Properties

expand all

Number of arms of the spiral, specified as 1 or 2.

Example: 'NumArms',1

Example: ant.NumArms = 1

Data Types: double

Number of turns in the spiral, specified as a scalar in meters. One turn length is taken as the length of a complete 360-degree revolution. To calculate the length of 1.25 turns, the first spiral is created up to one turn. Then the length of the second turn is scaled to the given fraction and added to the first turn length.

Example: 'NumTurns',2.0

Example: ant.NumTurns = 2.0

Data Types: double

Length of the first filament along the Y-axis from the origin to the midline of the strip width of the second filament, specified as a scalar in meters. InitialWidth is the width between the dashed violet color lines in the antenna image.

Example: 'InitialWidth',0.0050

Example: ant.InitialWidth = 0.0050

Data Types: double

Length of the second filament along the X-axis from the mid line of the first filament to half of the strip width of the third filament, specified as a scalar in meters. InitialLength is the width between the dashed orange color lines in the antenna image.

Example: 'InitialLength',0.0055

Example: ant.InitialLength = 0.0055

Data Types: double

Width of the strip, specified as a scalar in meters.

Example: 'StripWidth',5.0050e-04

Example: ant.StripWidth = 5.0050e-04

Data Types: double

Spacing between turns of the spiral, specified as a scalar in meters.

Example: 'Spacing',0.0015

Example: ant.Spacing = 0.0015

Data Types: double

Direction of the spiral turns (windings), specified as 'CW' or 'CCW'.

Example: 'WindingDirection','CW'

Example: ant.WindingDirection = CW

Data Types: char | string

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 load added to the antenna feed.

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

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.

Note

The wireStack antenna object only accepts the dot method to change its properties.

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'

Note

The wireStack antenna object only accepts the dot method to change its properties.

Data Types: double

Object Functions

showDisplay antenna or array structure; display shape as filled patch
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 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
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
returnLossReturn loss of antenna; scan return loss of array
sparametersS-parameter object
vswrVoltage standing wave ratio of antenna
rectspirallength2turnsCalculate number of turns for specified arm length in rectangular spiral antenna

Examples

collapse all

Create and view a default rectangular spiral antenna.

ant = spiralRectangular
ant = 
  spiralRectangular with properties:

             NumArms: 2
            NumTurns: 1.5300
        InitialWidth: 0.0010
       InitialLength: 0.0015
          StripWidth: 4.0500e-04
             Spacing: 0.0011
    WindingDirection: 'CCW'
                Tilt: 0
            TiltAxis: [1 0 0]
                Load: [1x1 lumpedElement]

show(ant)

Plot the radiation pattern of the antenna at the default frequency.

pattern(ant,7.65e9)

Create a rectangular spiral antenna object with two arms and two turns.

ant_d = spiralRectangular('NumArms',2,'NumTurns',2,'InitialLength',1e-3,...
           'InitialWidth',1e-3,'Spacing',0.5e-3,'StripWidth',0.5e-3);

Back the spiral using a reflector antenna object.

    r = reflector('Exciter',ant_d,'GroundPlaneLength',15e-3,'GroundPlaneWidth',...
        15e-3,'Spacing',2e-3,'Substrate',dielectric('FR4'));
    figure;
    show(r);

Plot the radiation pattern of the antenna at the specified frequency.

    figure;
    pattern(r,8e9);

Create a single arm rectangular spiral antenna with a total arm length of 291 mm.

ant = spiralRectangular('NumArms',1,'NumTurns',3,'InitialLength',4.5e-3,...
              'InitialWidth',4.5e-3,'Spacing',3.3e-3,'StripWidth',1.2e-3);
nT = rectspirallength2turns(ant,291e-3);
ant.NumTurns = nT;
figure;
show(ant); 

References

[1] Nakano, H., H. Yasui, and J. Yamauchi. “Numerical Analysis of Two-Arm Spiral Antennas Printed on a Finite-Size Dielectric Substrate.” IEEE Transactions on Antennas and Propagation 50, no. 3 (March 2002): 362–70. https://doi.org/10.1109/8.999628.

[2] Nakano, H., J. Eto, Y. Okabe, and J. Yamauchi. “Tilted- and Axial-Beam Formation by a Single-Arm Rectangular Spiral Antenna with Compact Dielectric Substrate and Conducting Plane.” IEEE Transactions on Antennas and Propagation 50, no. 1 (January 2002): 17–24. https://doi.org/10.1109/8.992557.

Introduced in R2020a