An analysis of the electrical performance of a microstrip patch antenna loaded with a periodic array of metamaterial resonators is presented in this work. Hexagonal complementary split ring resonators (CSRRs) are selected as metamaterial particles to be embedded in a conventional patch antenna. Geometrical parameters of the array of resonators are varied in order to evaluate the frequency response and radiation performance of the proposed antenna. A reduction of 5.7% in the resonance frequency is achieved with the metamaterial inclusions, while the return loss are improved to a value of -34 dB for 2GHz. The radiation performance is unchanged while the gain of the antenna is increased. Simulation and measured results are presented and show that the metamaterial array allows size reduction and gain improvement.