phased.CrossedDipoleAntennaElement System object

Package: phased

Crossed-dipole antenna element

Description

The phased.CrossedDipoleAntennaElement System object™ models a crossed-dipole antenna element. A crossed-dipole antenna is often used for generating circularly polarized fields. A crossed-dipole antenna is formed from two orthogonal short-dipole antennas, one along y-axis and the other along the z-axis in the antenna's local coordinate system. This antenna object generates right-handed circularly polarized fields along the x-axis (defined by 0° azimuth and 0° elevation angles).

To compute the response of the antenna element for specified directions:

  1. Define and set up your crossed-dipole antenna element. See Construction.

  2. Call step to compute the antenna response according to the properties of phased.CrossedDipoleAntennaElement. The behavior of step is specific to each object in the toolbox.

Construction

h = phased.CrossedDipoleAntennaElement creates the system object, h, to model a crossed-dipole antenna element.

h = phased.CrossedDipoleAntennaElement(Name,Value) creates the system object, h, with each specified property Name set to the specified Value. You can specify additional name-value pair arguments in any order as (Name1,Value1,...,NameN,ValueN).

Properties

FrequencyRange

Antenna operating frequency range

Antenna operating frequency range specified as a 1-by-2 row vector in the form of [LowerBound HigherBound]. This defines the frequency range over which the antenna has a response. The antenna element has no response outside the specified frequency range.

Default: [0 1e20]

Methods

cloneCreate crossed-dipole antenna object with same property values
directivityDirectivity of crossed-dipole antenna element
getNumInputsNumber of expected inputs to step method
getNumOutputsNumber of outputs from step method
isLockedLocked status for input attributes and nontunable properties
isPolarizationCapablePolarization capability
plotResponsePlot response pattern of antenna
releaseAllow property value and input characteristics changes
stepOutput response of antenna element

Examples

expand all

Plot Response of a Crossed-Dipole Antenna

Examine the response patterns of a crossed-dipole antenna used in an L-band radar with a frequency range between 1-2 GHz.

First, set up the radar parameters, and obtain the vertical and horizontal polarization responses at five different directions: elevation angles -30, -15, 0, 15 and 30 degrees, all at 0 degrees azimuth angle. The responses are computed at an operating frequency of 1.5 GHz.

scd = phased.CrossedDipoleAntennaElement(...
    'FrequencyRange',[1,2]*1e9);
fc = 1.5e9;
resp = step(scd,fc,[0,0,0,0,0;-30,-15,0,15,30]);
[resp.V, resp.H]
ans =

  -1.0607 + 0.0000i   0.0000 - 1.2247i
  -1.1830 + 0.0000i   0.0000 - 1.2247i
  -1.2247 + 0.0000i   0.0000 - 1.2247i
  -1.1830 + 0.0000i   0.0000 - 1.2247i
  -1.0607 + 0.0000i   0.0000 - 1.2247i

Next, draw a 3-D plot of the combined polarization response.

plotResponse(scd,fc,'Format','Polar',...
    'RespCut','3D','Polarization','C');

Algorithms

The total response of a crossed-dipole antenna element is a combination of its frequency response and spatial response. phased.CrossedDipoleAntennaElement calculates both responses using nearest neighbor interpolation, and then multiplies the responses to form the total response.

References

[1] Mott, H., Antennas for Radar and Communications, John Wiley & Sons, 1992.

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