how to find out the aperture of an antenna?

[routh]

Usually how to find out the aperture of an antenna? By measurement or simulation?
Is there somewhere the aperture for frequently used antenna can be found?
I can see the aperture values of some antennas are listed in Wiki, e.g. the aperture for half-wave dipole is 0.1305*lamda^2
but I would like to know the dimension of the aperture, e.g. width*length
this is because this dimension is needed for the calculation of far field condition
Thanks!

 

[kripacharya]

You might want to look into radiation patterns and 3db points etc as a definition for 'aperture'. There is lots n lots of publications on this aspect.

But i'm sure you know that already.

cheers!