Wikipedia: Fan art or fanart is artwork that is based on a character, costume, item, or story that was created by someone other than the artist.
If you, as an "artist," create art that is based on any existing art, you are creating Fanart. It doesn't matter if you draw it in your own style or create your own characters. If it is not your original idea all together, you did not create it.
I understand the merit of developing ones own style; however, if your reason for drawing/painting/etc. is to honor a series or artist that you love, what is wrong with doing a reproduction? I find the increasing number of fan artists I see telling other fan