Triangular lattice Electromagnetic Band-Gap (EBG) Structure in the ground plane is used in the design of a Triangular Micro-strip Patch Antenna (TMPA) Array to improve its bandwidth. The patch elements are equilateral triangular in shape. The Equilateral Triangular Micros-trip Patch Antenna (ETMPA) Array design has four patch elements in 2?2 form with ground plane having circular cutouts forming triangular lattice EBG. The ETMPA array with EBG provides better antenna gain and bandwidth. The ETMPA Array with EBG gives an impedance bandwidth of 16.76GHz and a percentage bandwidth of 110% while ETMPA Array gives an impedance bandwidth of 2.46GHz and a percentage bandwidth of 17.7%, thus an increment of approximately 500% in impedance bandwidth is observed.