phased.CrossedDipoleAntennaElement System object

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.

Note

Starting in R2016b, instead of using the step method to perform the operation defined by the System object, you can call the object with arguments, as if it were a function. For example, y = step(obj,x) and y = obj(x) perform equivalent operations.

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

directivity	Directivity of crossed-dipole antenna element
isPolarizationCapable	Polarization capability
pattern	Plot crossed-dipole antenna element directivity and patterns
patternAzimuth	Plot crossed-dipole antenna element directivity or pattern versus azimuth
patternElevation	Plot crossed-dipole antenna element directivity or pattern versus elevation
plotResponse	Plot response pattern of antenna
step	Output response of antenna element

Common to All System Objects
release	Allow System object property value changes

Examples

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 = 5×2 complex

  -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.

pattern(sCD,fc,[-180:180],[-90:90],...
    'CoordinateSystem','polar',...
    'Type','powerdb',...
    'Polarization','combined')

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.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• pattern, patternAzimuth, patternElevation, and plotResponse methods are not supported.

• See System Objects in MATLAB Code Generation (MATLAB Coder).