A planar square patch antenna with various meta-structures, such as circular-shaped complementary split ring resonator (CSRR), square-shaped CSRR, and modified D-shaped CSRR, is investigated in this paper. A shift in resonance frequency and multiband operation are achieved by loading an array of CSRR (circular, square, or D-shaped) on the ground surface of the antenna. The operational bands of the antennas can be easily tuned by varying the dimensions of the meta-structures. A comparison of three antenna designs is performed and presented. The medium parameters of the modified D-shaped CSRR are also calculated in order to validate its metamaterial behavior.