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rhombic

Create a rhombic antenna

Description

The rhombic object creates a rhombic antenna. It consists of a rhombus with a feed at one acute angles and a termination resistor at the other acute angle. It has a simple design and is highly directional. These antennas are used in shortwave radio broadcasting and point-to-point communications.

Rhombic antenna geometry, default radiation pattern, and impedance plot.

Creation

Description

example

ant = rhombic creates a rhombic antenna. The dimensions are chosen for resonant frequency of 515 MHz. The default rhombic antenna is fed at one acute angle and the other acute angle is terminated with a load of 500 ohms.

ant = rhombic(Name,Value) sets Properties using one or more name-value pairs. For example, ant = rhombic('ArmLength', 3) creates a rhombic antenna with an arm of length 3 meters.

Properties

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Length of each of the rhombus, specified as a scalar in meters.

Data Types: double

The acute angle between the adjacent arms at the feed location, specified as a scalar in degrees.

Data Types: double

Width of the arm of the rhombus, specified as a scalar in meters.

Data Types: double

Lumped elements added to the antenna feed, specified as a lumpedElement object. The load element is located opposite the feed at one of the acute angles of the rhombus. For more information, see lumpedElement.

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

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

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'

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

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
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
sparametersS-parameter object
vswrVoltage standing wave ratio of antenna

Examples

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Create a default rhombic antenna.

ant = rhombic
ant = 
  rhombic with properties:

       ArmLength: 2
    ArmElevation: 20
           Width: 0.1000
            Tilt: 0
        TiltAxis: [1 0 0]
            Load: [1x1 lumpedElement]

View the antenna using the show function.

show(ant);

Plot the radiation pattern of the antenna at 515 MHz.

pattern(ant, 515e6);

References

[1] Decker, R. “The Influence of Gain and Current Attenuation on the Design of the Rhombic Antenna.” IRE Transactions on Antennas and Propagation 7, no. 2 (April 1959): 188–196.

Introduced in R2020b