Graphene offers a large potential to downscale antennas to the micrometer scale, due to its special dispersion relation and its ability to support plasmons in the THz frequency range. For an adequate performance of the antenna, graphene material quality is crucial. A high chemical potential, as well as a high relaxation time are needed. Fabrication and processing, as well as the material environment are very critical to achieve a high graphene quality and a good emissivity of the antenna. We demonstrate the simulation, fabrication and analysis of a graphene based plasmonic antenna structure acting as an active THz emission device.