Abstract: The uniform regular array antenna has poor sidelobe level and wide beamwidth, which is not suitable for demanding one-dimensional phased array radar systems. In response to these requirements, an irregular antenna array based on a series-fed network structure is proposed in this paper. The array takes a series feed method, combined with a microwave multilayer board technology with a hollow cavity, to avoid back radiation and obtain broadband characteristics simultaneously through a stripline slot coupling method. The array is optimized using a genetic algorithm to obtain a theoretical side lobe level below -18 dB. Compared to a uniform regular array, the beam width is only 0.2° widened. Compared with the beam width of 20 degree, the beam width extension can be ignored. The measured 2:1 standing wave bandwidth of the array is 19.8%, and the pattern bandwidth is 12.2%. Within the bandwidth of the pattern, the measured sidelobe level of the array is lower than -16 dB, and the measured gain of the array is higher than 11.7 dBi. The measured results show that the array is suitable for the application of one-dimensional phased array.