Here is the code of your problem:
if you have : mat = [ 1 2 3; 4 5 6; 7 8 9 ; 10 11 12 13];
leng = length(mat);
for i = 1:leng
var = ['A',num2str(i)];
xlswrite('data.xls',x(i,:),1,var);
end
Thats it
x(1,:) ----> 1 2 3 x(2,:) ----> 4 5 6 x(3,:) ----> 7 8 9 with for loop and so on...
var ---> A1,A2,A3.... with for loop