In this paper a Rectangular Patch Antenna is specifically designed and analysed using metamaterial concepts. Based on an ordinary patch antenna, it has a double C shaped resonant structure embedded in the centre of the substrate of the Rectangular Patch Antenna. The resonant structure has a strong electric response in a certain frequency of interest, and can be used to construct metamaterials with negative permittivity. It is found the great impact on the antenna performance to modify the dimension to 57% of a conventional patch antenna. This antenna has strong radiation in the 45