# Getting steered beam gain in Phased Array Toolbox

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Peter Wittenberg on 23 Dec 2022
Answered: Honglei Chen on 5 Jan 2023
If you use the pattern command in the Phased Array tool box, you can see the gain pattern that results. These are correct. Now, if you had, for example, a linear array, you can get the gain (directivity) correctly. However, when you put in steering commands, using steervec, for example, to produce a steering vector for use with the weights parameter, you can see your gain pattern does indeed steer to the desired angle. However, if we now compare the directivity that results from different beam steering angles, it is the same value regardless of where the beam is steered. I would like to be able to find the difference in directivity between different beam steering directions.
Of course, we know that there is an array factor that causes the cosine(theta) array factor rolloff, but I expected that would be taken into account in the Phased Array Toolbox calculation of pattern with a steered beam. While I could externally produce the effect of gain rolloff with angle, I'd like to know how to do it inside the Phased Array Toolbox so the array factor is included in the gain (directivity).
Does anyone know how to set up the Phased Arrray Toolbox to achieve it? If so, please provide an example.

Honglei Chen on 5 Jan 2023
Hi Peter,
Happy new year! The pattern() computation does take into consideration of beam broadening. However, uniform linear array is a bit special, as its directivity is fairly insenstive to the scanning angle (assuming using steering vector), especially if you set the spacing to half wavelength. You said you can see that roll off outside the tool, is that for linear array too? Are you using an isotropic antenna? If you can share your configuration, I can see if we could reproduce the result.
Thanks,
Honglei

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