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# AWR1642: Angular resolution of a non uniform array

Part Number: AWR1642

Hi,

I am referring  swra554 app note on angular resolution.  Can I assume the final angular resolution in azimuth or elevation depends only on maximum number of virtual Rx antennae in that dimension. i.e.: Non uniform array having 2 Rx virtual antennae in one column and 4Rx virtual Antennae in another column will have angular resolution of 2/4 rad(2/N).

Thanks

Siva

• Hello Siva,
For a non uniform array its not straight forward to estimate the angular resolution using the formula mentioned in the app note. This would need to be simulated.

Regards,
Vivek
• In reply to Vivek Dham:

Hi Vivek,

Thanks for the update.  I understand for uniform linear array 3dB bandwith equates to 2/N ( for large N).  Can this results be extended to non uniform planar array. i.e.: deriving the array factor for planar array and get the 3dB BW to get angular resolution?

Another question raises : If we take only highest number of elements in a non uniform planar array and do angular FFT for that, can we expect angular resolution of 2/N ? Obviously we will be losing energy from other FFT points?

Thanks

Siva

• In reply to Siva Vinay:

Just to be accurate for ULA 3dB BW ~= 2/N
• In reply to Siva Vinay:

Hi,

Do you have any update on this question?

Thanks

Siva

• In reply to Siva Vinay:

The formulas in the app-note are only for uniform linear arrays with a spacing of lambda/2

I am not aware of any generic formula for the resolution of a non-uniform array.
However in general,
(a) the resolution will increase with the total length of the antenna (distance from the first element to the last element).
(b) when there is non-uniform spacing and spacing greater than lambda/2, then the side-lobe level tends to increase.
[see attached example, where array B has better resolution (narrower peak), but greater side-lobes]