The design of four element microstrip patch antenna array with rectangular slots is presented in this paper. This is simulated and analysed in detail by using Mitered bend feed network which is used in wireless application in ISM frequency bands. HFSS 13.0 is used to accomplish this work; besides, its fabrication is done by using photolithography technique, devised by “FR4-epoxy” substrate. VNAE507IC is devised to test patch. Improved Gain, Directivity and Bandwidth in contrast with declined Reflection coefficient and VSWR together with multiband frequency responses are the characteristics of slot antenna.