In a phased array antenna system, beamforming integrated circuit (IC) is located directly behind the antenna and uses a multi-layer printed circuit board (PCB). As the frequency band becomes higher, the direct via feed method is not suitable for multi-layer PCB structure due to the decrease of transmission characteristics and the increase of manufacturing difficulty by use of blind via. This paper introduces the antenna using an aperture coupled feeding technique on multi-layer PCB for a Ku-band phased array antenna system. To verify the design, an antenna prototype is developed and measured at Ku-band for satellite applications. The antenna operates with left-handed circular polarization (LHCP) at center frequency of 11.9GHz and a peak gain of 15.2dBic.