Can we change the beamwidth in Phased Array System Toolbox?

Dear MATLAB team,

Is there some way to alter the beamwidth in the Phased Array System Toolbox? As far as we know, we can plot the "3D response pattern" of an antenna array, which has the colorful beamforming slopes, however, we are not sure if there is some parameter that can alter the beamwidth.

Regards, Ralph

Answer 1

[Honglei Chen]

Hi Ralph,

I'm not sure if I get what exactly you ask for. In general, the beamwidth is altered if a set of weights is applied to an array or a thinning operation is applied to an array. Is this what you are asking? Thanks.

[Ralph]

Hi Honglei,

Thank you so much for your reply. If possible, could you please give an example about what you are describing?

Thanks, Ralph

[Honglei Chen]

Hi Ralph,

The following example is a good start. You can see that by applying a Taper or a thinning, the beamwidth changed.

http://www.mathworks.com/help/phased/examples/tapering-thinning-and-arrays-with-different-sensor-patterns.html

HTH

[Ralph]

Hi Honglei,

I think I need to clarify my question. I would like to change the so-called "beamwidth" in this way: under the condition that the beamforming direction is fixed, change the main lobe width.

Thanks, Ralph

[Honglei Chen]

Well, in general no taper gives you the best beamwidth. If you add a taper to the array, the beamwidth will grow, but the sidelobe gets suppressed. For example,

N = 8;
myArray = phased.ULA(N,0.5);
plotResponse(myArray,3e8,3e8,'Weights',ones(N,1))
hold on;
plotResponse(myArray,3e8,3e8,'Weights',hamming(N))

You can see the difference in the beamwidth, one from no weights/taper, the other one from a Hamming taper.

[Ralph]

Thank you a lot, Honglei. Also, is it possible to change the beamwidth, for example, from 10 or 20 degree to 90 degree dynamically? Also assume that the main lobe's direction is fixed. If I am wrong, please correct me -- I notice the change of beamwidth by using this taper/thinning method is kind of limited?

Thanks, Ralph

[Honglei Chen]

Hi Ralph, yes the taper has some limitations if you just use those pre-defined windows. I don't quite understand what you mean by changing a beamwidth from 10/20 degrees to 90 degrees, that's quite a difference and looks to me you almost changed the operation mode. This being said, you could consider turning off certain elements to achieve that, for example

N = 8;
myArray = phased.ULA(N,0.5);
plotResponse(myArray,3e8,3e8,'Weights',ones(N,1))
hold on;
plotResponse(myArray,3e8,3e8,'Weights',[zeros(3,1);zeros(2,1);zeros(3,1)])

You can change the weights any time you want so it is dynamic.

HTH

[Ralph]

Thanks a lot, Honglei. This indeed meets our demand.