-7 dB is pretty good for microstrip antenna. Normally its input resitance is quite high and one uses quarter wave transformer for impedance match. Check from simulation smith chart the input impedance Zin and then use a quarter wavelength microstrip transmission line of Zo = sqr root(Zinx50) to match it with 50 ohms line.

Your Design is not correct please correct it.

Dear Vikash Saw ,

I am new to this work can you suggest, where should i change and correct my design.If you have any models or techniques for designing to get better results can you share it to me. I will make it use to get better results.

Dear praveen, please specify the specification of your antenna you are interested to design. Frequency at which You want to resonate. Also I would like to suggest you first learn to design patch antenna because it is a simple one and you can find videos from youtube.

You matching needs to be worked out. A look into the Circuit and layout is required to answer your query.