follow my paper gain enhancement using array.

u can read this article

Array feeding networks can be designed with the help of Wilkinson Power dividers or using the concept of parallel striplines.

one simple method is using of corporate feed. in the design procedure you should calculate microstrip line width to achieve desired impedance. utilizing power dividers such as T_junction or wilkinson is also necessary.

Thanks everyone to response....

but, I need a good material for designing of feeding networks and design rules and formula for feeding networks.

hey sidhartha,

http://shodhganga.inflibnet.ac.in/bitstream/10603/54875/17/17_chapter%205.pdf

again this would be helpful.