function rfa_2_s2p(file_name)

    p = strfind(file_name,'.');
    name=file_name(1:(p-1));
    load(file_name,'-mat');
    out=[name,'.s2p']
    fid=fopen(out,'wt+');
    
    fprintf(fid,'# MHz S DB R 50\n');
    fprintf(fid,'! S-Parameters data from HP 8505, Dick Benson\n');
    fprintf(fid,'!!     FREQ            dbS11         angS11        dbS21         angS21        dbS12         angS12        dbS22         angS22  \n');
 
    fvec = data.s(1,1).freq;
    L    = length(fvec);
    
    for k=1:L
        fprintf(fid,' %12.4f  %12.4f  %12.4f  %12.4f  %12.4f  %12.4f  %12.4f  %12.4f  %12.4f\n',...
                data.s(1,1).freq(k),...
                data.s(1,1).mag(k),data.s(1,1).ph(k),...
                data.s(2,1).mag(k),data.s(2,1).ph(k),...
                data.s(1,2).mag(k),data.s(1,2).ph(k),...
                data.s(2,2).mag(k),data.s(2,2).ph(k));
    end;
    fclose(fid);