spiralRectangular

Create rectangular spiral antenna on xy-plane

Since R2020a

Description

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

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.

Creation

Syntax

sr = spiralRectangular

sr = spiralRectangular(Name=Value)

Description

sr = spiralRectangular creates a default rectangular spiral antenna object with default property values. The default dimensions are chosen for an operating frequency of around 7.65 GHz.

sr = spiralRectangular(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, sr = spiralRectangular(NumArms=1) creates a planar rectangular spiral antenna with a single arm.

Properties

NumArms — Number of arms of spiral

2 (default) | 1

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

Example: 1

Data Types: double

NumTurns — Number of turns in spiral

1.53 (default) | scalar

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: 2

Data Types: double

InitialWidth — Length of first filament along y-axis

0.0010 (default) | scalar

Length of the first filament along the y-axis from the origin to the mid-line 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: 0.0050

Data Types: double

InitialLength — Length of second filament along x-axis

0.0015 (default) | scalar

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: 0.0055

Data Types: double

StripWidth — Width of strip

4.0500e-04 (default) | scalar

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

Example: 5.0050e-04

Data Types: double

Spacing — Spacing between turns

0.0011 (default) | scalar

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

Example: 0.0015

Data Types: double

WindingDirection — Direction of spiral turns (windings)

"CCW" (default) | "CW"

Direction of the spiral turns (windings), specified as "CW" (clockwise) or "CCW" (counter-clockwise).

Example: "CW"

Data Types: string

Conductor — Type of metal material

"PEC" (default) | metal object

Type of the metal used as a conductor, specified as a metal material 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: 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: Load=lumpedElement(Impedance=75)

Example: antenna.Load = lumpedElement(Impedance=75)

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	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
rectspirallength2turns	Calculate number of turns for specified arm length in rectangular spiral antenna
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

Default Rectangular Spiral Antenna

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'
           Conductor: [1x1 metal]
                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)

Radiation Pattern of Reflector Backed Rectangular Spiral

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);

Rectangular Spiral Antenna with Specified Arm Length

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.

Version History

Introduced in R2020a