This document discusses using a genetic algorithm to optimize the resonant frequency of a coaxially fed rectangular microstrip antenna. The genetic algorithm optimizes patch length, width, and feed position at frequencies of 3GHz, 5GHz, and 10GHz. Results showed the optimized antennas had return losses of -18.7dB, -22.03dB, and -41.75dB respectively at the desired frequencies, indicating good impedance matching. Radiation patterns were also verified to show forward radiation and no backward radiation, validating the design accuracy. The use of genetic algorithms for antenna design optimization encourages accurate resonant frequency evaluation.