Abstarct: The purpose of this thesis is on the design and development of an aperture coupling microstrip array antenna with high gain, high bandwidth, low side-lobe level for FMCW radar. A microstrip array antenna with high bandwidth, high gain and low side-lobe level, is a huge need for today and the future of industrial, military, and radar communication systems. In designing such an array of substrate types, its thickness, the spacing between the elements, the feed lines, and their combination together, is important in obtaining a high gain, appropriate side-lobe level, bandwidth, mutual coupling is very important that consider the design of the structure. Work with optimally design of element started. Then, the complete 512 element array was fed to all the elements by feeding and distributing the same power and gain was obtained over 30 dB. To reduce the side-lobe level, the feed network is designed with Taylor distribution so that the specific range required for each element, which is different from the other elements, is obtained and also, all elements of the array are fed in phase. The elements that are in the middle of the array receive the most power and the elements that are in the besides of the array receive the least power. This structure is designed with 512 elements in an array of 32 × 16, and the operating frequency of the antenna is 12.5 to 14.9 GHz, equivalent to 17% of bandwidth in the Ku band. The gain of this antenna is 29 dB and gain variations over the entire frequency range is low, which is desirable and the side-lobe level also varies between -22 dB and -29 dB on both of the E-plane and H-plane. Finally, a mextal reflector plate was used to lower the Backlobe level, reaching F/B levels above 30 dB. The overall dimensions of the antenna are 576 mm * 288 mm.