This may be your quickest solution...

http://ece.wpi.edu/books/aemm/

If you are open to other methods, Sullivan has the code for finite-difference time-domain analysis of a patch antenna in his book.

http://www.astrosen.unam.mx/~aceves/Fisica_Computacional/ebooks/sullivan_emsimulation_fdtd.pdf

@Raymond Rumpf: Thank you very much for your response.

To design width and length of an antenna, we can easily done with simple matlab codes. but while define radiation pattern, its continues Fourier series form. Try to follow  PHASED ARRAY TOOLBOX in MATLAB website to get idea about to design radiation pattern. Good Luck

Dr Raymond's links are very useful

Hai Dear,

Kindly refer the RF Antenna tool box in MTLAB .You cn directly design as per the requirement and Code can synthesized.

BOOK:Antenna and EM Modeling with MATLAB

Code:

https://bcs.wiley.com/he-bcs/Books?action=resource&bcsId=8971&itemId=0471218766&resourceId=35528