A novel concept of SIW cavity-backed dual inverted edge curved L slots antenna array with the defective ground plane is proposed in this paper. A linearly placed six-element inverted dual L slots array antenna is designed separated by a distance of 0.55λg to achieve high gain. Each pair of slots is separated by a column of the vias to form sub-cavities and those are fed individually. Defective ground structure (DGS) is introduced at the ground plane to manage the propagation of wave to the last slots in the array. The slots are enclosed by a SIW cavity of height 0.24λg in a single substrate. A measured peak gain of 8 dBi is achieved at 14.29 GHz. The antenna shows a front-to-back ratio of 24.9 dB. The design is also compared with various aspects to show the advantages of each element introduced in the design. The validity of the design is proved by the good agreement between the simulated and measured results. This novel design can be used to achieve the performance requirement of a satellite antenna working in Ku band.