In this paper, we proposed a Ku-band antenna that can be mounted on UAV. A proposed antenna structure has small size and light weight. It is considered long distance communication environment(LOS) and equipped UAV. Proposed antenna is designed $16{ imes}2$ aperture coupled microstrip patch array antenna for high gain characteristics. In the measurement results, VSWR is less than 1.5 and the gain is over 21dBi in the bandwidth. Mechanical specifications of antenna assembly are ${phi}250{ imes}200mm$ of size and 3kg of weight.