This paper presents a 35 GHz patch microstrip antenna array on an organic LCP (Liquid Crystal Polymer) substrate. To achieve a higher gain and narrower 3 dB beamwidth, a 4×4 antenna array has been designed and simulated using a 2×2 antenna array as unit array. The results show that an 18.9 dBi of gain and a 3 dB beamwidth of 20.7degrees.