why antenna admittance is measured?

Hi

we have various parameter to see the performance of antenna like impedance, pattern etc...But i saw in some paper they hav calculated admittance ( for eg: to show the effect of monopole on box when it is located in center,edge,corner)..Can any one explain me why so?

Thanks

Hi,
iam not sure, but I think - my idea - if you want use admittance part of Smith diagram to matching, you need to know admittance of antenna..... and admittance=1/impedance.....

In general, antenna matching is done by shunting C or L, So calculations in admittance will ease.