MATLAB: Find the sidelobe level

antennasidelobe level

greetings.,

i worked on my graph plotting the radiation pattern of an antenna array. so., could anyone help me about findin the amplitude of the first sidelobe?? please…

Best Answer

If you have Signal Processing Toolbox, you can use findpeaks function to find peaks. In your case, if you find two biggest peaks then the second one should be your first sidelobe. You can see if you have the license for Signal Processing Toolbox by running following command

>> ver

The findpeaks function has been shipping since R2007b. It also gets a major improvement during R2010a.

HTH

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MATLAB: In phased array toolbox, what is the difference between rootmusicdoa and phased.RootMUSICEstimator functions

They do the same thing, the difference is on interfaces. rootmusicdoa takes the covariance matrix as input while phased.RootMUSICEstimator take the row data as input. The RootMUSICEstimator can also help you estimating the number of sources in the signal. But you can use either one of them to achieve your goal depending on what kind of data you have.

HTH

MATLAB: Directivity did not match our expectation

Hi Ralph,

In this example you are using an isotropic antenna element. So even though in this cut the beam is more focused, it has strong lobe all around the array axis, so in some sense the energy is not well focused.

If we change the element type to a more realistic pattern, such as cosine antenna pattern, then you can see the directivity of the ULA starts to be better than the URA

figure
ha = phased.ULA('NumElements',16,'Element',phased.CosineAntennaElement);
plotResponse(ha,3e8,3e8,'RespCut','Az','Format','Polar','Unit','dbi');
hold on;
ha = phased.URA('Size',[4 4],'Element',phased.CosineAntennaElement);
plotResponse(ha,3e8,3e8,'RespCut','Az','Format','Polar','Unit','dbi');

If you use a Hertzian dipole, the ULA is also better

figure
ha = phased.ULA('NumElements',16,'Element',phased.ShortDipoleAntennaElement);
plotResponse(ha,3e8,3e8,'RespCut','Az','Format','Polar','Unit','dbi');
hold on;
ha = phased.URA('Size',[4 4],'Element',phased.ShortDipoleAntennaElement);
plotResponse(ha,3e8,3e8,'RespCut','Az','Format','Polar','Unit','dbi');

In short, I'm not saying that you are wrong since I don't really have a theoretical result to back me up. But I'm also not convinced that the toolbox is giving the wrong answer. If you do have a number that I can compare to, please let me know and I'd love to take a look.

Thanks

Best Answer

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MATLAB: In phased array toolbox, what is the difference between rootmusicdoa and phased.Roo​tMUSICEsti​mator functions

MATLAB: Directivity did not match our expectation

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MATLAB: In phased array toolbox, what is the difference between rootmusicdoa and phased.RootMUSICEstimator functions