On the GAMMA 10 tandem mirror, Magneto Hydro Dynamic (MHD) stabilization is kept with high pressure plasmas in the minimum-B anchor cell. To enhance ion heating in the anchor cell, direct anchor heating is introduced with an anchor antenna. The enhancement of the anchor heating is clearly observed. However, the antenna loading is very small in the case of strait bar-type antenna. In this paper, a newly designed antenna is introduced for the anchor heating. The antenna shape is improved to be an elliptical shape for matching the plasma shape. Three dimensional numeral simulation is introduced for the evaluation antenna loading with the antenna shape. Remarkable improvement is observed both in the experiment and in the simulation.