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Analyze Cylindrical Reflector Antenna with Horn Array Feed

This example shows how to analyze an antenna consisting of a cylindrical reflector with a linear array of horns.

Create Horn Antenna

Create a horn antenna resonating at 10 GHz. Set lambda to the free space wavelength at the design frequency of 10 GHz.

freq = 10e9; 
lambda = physconst('light')/freq; 
h = design(horn,10e9);
h.FlareWidth = 0.0416;
h.FlareLength = 0.0416;
h.FlareHeight = 31.8e-3; 
h.Length = 21e-3; 
h.FeedOffset(1) = -3.6e-3; 
figure;
show(h)

Figure contains an axes object. The axes object with title horn antenna element contains 3 objects of type patch, surface. These objects represent PEC, feed.

Plot VSWR and Radiation Pattern of Horn Antenna

Plot the voltage standing wave ratio (VSWR) of the horn antenna over the frequency range of 8.5–12.5 GHz.

range = (0.85:0.01:1.25)*freq; 
figure;
vswr(h,range); 
ylim([0 5]);

Figure contains an axes object. The axes object with title VSWR contains an object of type line.

The VSWR of the horn antenna is less than 2 between 8.6–12.2 GHz.

Plot the radiation pattern of the horn antenna.

figure;
pattern(h,freq);

Figure contains an axes object and other objects of type uicontrol. The axes object contains 3 objects of type patch, surface.

The directivity of the antenna is 11.4 dB.

Create Linear Array of Horns

Create a linear array of horns. Set the number of elements in the array to 4 and the spacing between the elements to 1.5 times of lambda.

arr = linearArray('Element',h,'NumElements',4);
arr.Element.Tilt = -90; 
arr.Element.TiltAxis = 'Z';
arr.ElementSpacing = 1.5*lambda; 
figure;
show(arr)

Figure contains an axes object. The axes object with title linearArray of horn antennas contains 12 objects of type patch, surface. These objects represent PEC, feed.

Create Cylindrical Reflector with Horn Array

Create a cylindrical reflector with the linear array of horns as the exciter. Tilt the exciter at an angle of 90 degrees along the Z-axis and 70 degrees along the Y-axis.

ref = reflectorCylindrical; 
ref.GroundPlaneLength = 10.2*lambda; 
ref.GroundPlaneWidth = 10.3*lambda; 
ref.Spacing = 8.5*lambda; 
ref.Tilt = 90; 
ref.Exciter = arr; 
ref.Exciter.Tilt = [90 70];
ref.Exciter.TiltAxis = ['Z','Y']; 
figure;
show(ref)

Figure contains an axes object. The axes object with title reflectorCylindrical antenna element contains 11 objects of type patch, surface. These objects represent PEC, feed.

Mesh and Plot Radiation Pattern of Cylindrical Reflector with Horn Array

Mesh the reflector manually with the maximum edge length of lambda/10.

figure;
mesh(ref,'MaxEdgeLength',lambda/10);

Figure contains an axes object and other objects of type uicontrol. The axes object with title Metal mesh contains 5 objects of type patch, surface.

Load the solved reflector file refObj.mat.

load("refObj.mat");

Plot the radiation pattern.

figure;
pattern(ref,freq);
view([80 10]);

Figure contains an axes object and other objects of type uicontrol. The axes object contains 11 objects of type patch, surface.

You can also plot the radiation pattern without using the MAT file, but the pattern(ref,freq) command takes up to 18 minutes to plot the radiation pattern. To run the pattern(ref,freq) command, these machine configurations are preferred:

  • Processor: Intel ® Xeon ® CPU E5-1650 v4 @3.60GHz.

  • RAM: 64GB.

  • System type: 64-bit operating system.

The directivity of the cylindrical reflector antenna with a horn array feed is 18.7 dB.

See Also

Related Topics

References

[1] Zhang.R, Z. Xie and Q. Chu. "A New Horn Array Feed for Parabolic Cylindrical Reflector Antenna." 2007 Asia-Pacific Microwave Conference, 2007, pp.1-4. doi: 10.1109/APMC.2007.4555169.