Re: need some help pls.
Is this your choice, or did some professor make you take it.
I guess it depends on the parameters of your assignment. If you want to improve the gain of a single patch antenna, I think you are out of luck, as they have been pretty much optimized by now. Just search the literature.
If you have more flexibility in the project, you could investigate:
1) using multiple patches, properly phased, to "squnt" the reception pattern to give you more apparent gain for your system orientation
2) you could use multiple patches, phase steered automatically, to "point" the antenna in a specific direction
3) you could use a singl patch, but with switchable feed points, to select one or the other polarizaiton. Assuming the received signal undergoes polarization rotation while it gets to you, you might want either vertical OR horizontal polarization for the strongest received signal
4) you could use tunable elements (like varactor diodes) to tune a narrowband patch to work at peak efficiency over a much broader frequency span