Hi,
Under microstrip antennas, which shape are you looking for like microstrip slot, microstrip circular patch, rectangular etc...
Because depending upon shape you can start design antenna acouring to spec.
Let take microstrip slot antenna for example , for that you need to calculate using operating frequency,
1. slot width.
2. slot length.
3. feed line length
4. stud length.
5. Impedance
etc....
Similarly you can design other shape patch antennas.
Their is one book "Microstrip patch antennas" authored by Bhel-Bhel. This is very good book for microstrip antennas.
Regards
Animesh