The automatic design of microstrip antennas involves a series of continuous parameters to be optimized and multiple objectives to be simultaneously fulfilled. When the shape of the patch is admitted to be amorphous, discrete parameters are added to the optimization stage. Here, we are proposing a hybrid-coded genetic algorithm to implement the search engine. Due to the existence of several attributes of the antenna to be simultaneously optimized, and given that they keep intricate relations among each other, the design process incorporates a comparative analysis of the electromagnetic properties presented by the obtained theoretical configuration and the effective response produced by the corresponding physical prototype. © 2007 IEEE. 329333Bahl, I., Bhartia, P., (1980) Microstrip Antennas, , Artech HousePosar, D.M., Schaubert, D.H., (1995) Microstrip Antennas, New Y, , IEEE PressSplitt, G., (1993) Efficient numerical Techniques for the analysis of complex microstrip antennas and arrays, , PhD dissertation, European space Agency -TT-1259Kaemakar, N.C., Bialkowski, M.E., Experimental investigations into an electromagnetically coupled microstrip patch antenna (1992) Microwave and Optical Technology Letters5(9): 447-453Splitt, G., Davidovits, M., Guidelines for design of electromagnetically coupled microstrip patch antennas in two layer substrates (1997) Antennas and Propagation Magazine, IEEE, 45 (7), pp. 1117-1122Delabie, C., Villegas, M., Picon, O., Creation of new shapes for resonant microstrip structures by means of genetic algorithms (1997) Electronics Letters, 33 (18). , AugJohnson, J.M., Rahmat-Samii, Y., (1999) Electromagnetic Optimization by Genetic Algorithms, , New York: Wiley-InterscienceChoo, H., Hutani, A., Trintinalia, L.C., Ling, H., Shape optimization of broadband microstrip antennas using genetic algorithm (2000) Electronics Letters, 36 (25). , DecBack, T., Fogel, D.B., Michalewicz, Z., (2000) Evolutionary Computation I e II, , Bristol: Institute of Physics PublishingBarra, T., (2007) An Evolutionary Framework for Microstrip Antennas, , Master Thesis, University of Campinas UNICAMP, Campinas, Brazil, Jan, In PortugueseD. E. Goldberg Genetic Algorithms in Search, Optimization, and Machine Learning. New York: A. W. 1989J. H. Holland Adaptation in Natural and Artificial Systems. Ann Arbor: University of Michigan Press, 1975