function gewdbi = gain(ant,freq)
% gewdbi = gain(ant,freq)
% Antenna gain in x-direction in dBi
%
% ant  :  antenna description.  There are three options:
%         MATLAB expression :   description in MADL
%         string :   file with description in NEC-syntax
%         {string; p} : string = file with description in AAL-syntax; 
%                       p = antenna parameters
%
% freq :  frequency in MHz.
