How to design antenna array using binomial polynomial?

dear ALL,

i need to design a microstrip patch antenna to be directive. My supervisor asked me to use binomial distribution for a element antenna.

the coefficients is found out to be 1-3-3-1.

Now my question is how to get this coeeficients to be implemented on the antenna array?

I want to design a square patch antenna with 4 elements.

Can i use corporate feed?

how to get the power to be divided such as that?

Any suggestion?

Thank you for your help.