The National Institute of Information and Communications Technology (NICT) has been developing an on-board Ka-band tracking antenna system which realizes the communication link between unmanned aircraft (UA) and remote pilot via satellite with the increased use of UA research and standardization of the control communication system for UA. The tracking on-board antenna designed for UA has various functions such as low-profile and broadband. In this paper, we explain the results of the development and the background of the tracking antenna so far.