Techniques of miniaturization of patch antennas

Hello,
I work with patch antenna at 19-38 GHz, i want to decrease the size of the antenna and to expand the bandwidth , but i don't know which technique of miniaturization can i use, any help please!
Thank you in advance.

you can decrease the size of the antenna by choosing high dielectric material or you can also use shorting posts and pins.

Thank you sandeepkiranv, but what do you mean by using shorting posts and pins?