In this book,an original theoretical, numerical and simulation based realistic study of metamaterial loaded circular patch antenna has been described. Initially, basics of metamaterials and patch antennas have been discussed. Later,a novel technique to achieve multi-band performance in both reduced and conventional sized microstrip circular patch antennas loaded with metamaterial has been shown with mathematical derivation. Incorporation of symmetric slotting concept with the concept of additional mode modification in both ENG and MNG metamaterial loaded circular patch antennas have been shown. The use of metamaterial causes unconventional mode modification, whereas symmetrical slotting not only introduces another band but also improves the gain by around 1 dB of unconventional mode for MNG loaded antenna. In the first part of our research work,we have reported both dual and triple band conventional sized circular patch antenna partially loaded with ENG metamaterial.Later,both dual and triple band conventional sized circular patch antenna partially loaded with MNG metamaterials have been shown.We hope that our research will pave the way for a lot of new researchs in antenna system.