The Microstrip patch antenna has applications in several areas in today's world. In this article, a detailed design and investigation report of multi-band microstrip patch antenna for the WBAN applications is presented. In this design, the Flame Retardant-4 (FR-4) substrate is placed in between the top radiator and the ground plane. The physical size of the patch is 38 x 29.4 mm. There are several techniques available to create multiple resonant frequencies. Multi-band can be achieved using the Partial ground plane (PGP) technique, Band Gap structure materials, and by making slots in the patch. In this design, seven resonant frequencies are obtained by making slots in the patch. The optimization process is done by a parametric analysis approach in the Ansys HFSS tool. In this design, resonant frequencies are observed as 1.99, 4.22, 5.04, 5.56, 6.63, 7.57, and 8.07 GHz, which are suitable for S band and C band applications. Reflection Coefficient, Gain, VSWR, and Specific absorption rate (SAR) are measured for each resonating frequency with respect to free space and human phantom model. Antenna parameters were in the acceptable range and this design would work well with WBAN applications.