This document describes the design of a rectangular microstrip patch antenna operating in the S band (2-4 GHz) using the transmission line model. Key steps included calculating antenna parameters like width, effective dielectric constant, and length based on the transmission line model. An inset feed was used for impedance matching. Simulation results showed the input impedance matched the 50 ohm feed at the design frequency of 2.4 GHz. The return loss was minimized (-169.4 dB) and VSWR was close to the ideal value of 1, indicating good impedance matching. The antenna was concluded to be well designed for operation in the S band with a bandwidth of 4.16%.