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Directivity calculation in Matlab for circular array-suggestions?

Directivity calculation in Matlab for circular array-suggestions?

Directivity calculation in Matlab for circular array-suggestions?

Hi everyone,

Could someone help me out in calculating the Directivity of my circular array. I'm using Matlab and I'm pretty certain my method is not correct (explained a little below).

Very Briefly, this is how I generate the Array factor:


And inside a loop:

      for k=1:length(t)
      x=cos((t)+offset); y=sin((t)+offset);

And I plot it with:


And this is how the Array and the Array factor looks if that helps:

So now I have my Array factor AF1 which is a 501x501 array and here is where I could use some help in calculating the directivity.

I tried calculating the directivity this way:




But as I mentioned...I doubt this gives a correct value...I used linspace to set theta and phi to 501 so that the matrix dimensions match AF1...and I have no clue if the value I get is right.

Could someone help me out with the Directivity here?
Sorry if my query is too long but I thought it would help if I was as descriptive as possible.


RE: Directivity calculation in Matlab for circular array-suggestions?

Average directivity should be 0 dBi (assuming that the mass is constant *).

* subtle joke.

RE: Directivity calculation in Matlab for circular array-suggestions?

Directivity for most antennas is pretty accurate (in dB) as 10* log [41,000/[(beamwidth 1)*(beamwidth 2)]]. beamwidth 1&2 are principal planes in orthogonal (perpindicular) directions.
compare that to your results as a quick check, it should be within 1 dB unless those sidelobes in your chart are very high.


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