How to calculate the near field boundary or magnitude for 3.5 GHz antenna?

the boundary (distance ) is taken to be 2*D2/λ where D is the largest dimension of the antenna aperture.

Take a look here too:

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does this equation work with all shapes of antennas

It is a general guide and yes.

The idea is that the radiation pattern does not really solidify until you get away from the antenna and for most situations this is far enough away.

Much depends on the antenna and the application so this distance is just a guide.