This paper presents a parametric study of rectangular microstrip patch antenna and their effect on its performance. The antenna has been analyzed using commercially Sonnet 14.53 software based on method of moments (MoM) at resonance frequency of 1.691 GHz .The obtained results shows the effect of various parameters such as patch width, height, dielectric constant εr, dielectric loss
and feed point location on the resonance frequency, return loss, input impedance , bandwidth , directivity and VSWR