In this paper, a substrate integrated waveguide power divider is proposed on the basis of a recombinant topology that provides in-phase power division with an odd or even number of branches. The aim is to generate different types of power distribution to control sidelobe level in the antenna array. In this study, several power-divider designs were designed to demonstrate and validate the design approach. Each design consists of a cascade of steps and nfurcations, which were initially designed based on sinusoidal basis functions. These designs were simulated using the High Frequency Structure Simulator (HFSS) and shown to closely match the performance estimated using the basis functions. A substrate with thickness of 0.508 mm and dielectric constant of 2.94 is used. A three-way power divider with a binominal output taper is optimized and fabricated, showing good results in the bandwidth of interest from 72 to 81 GHz. Measurement results for a 3 × 8 slot array antenna designed in conjunction with the proposed feeding network are presented and discussed. This design can be used to build up rectangular waveguide structures. The novel structure is expected to be useful in building sub-arrays of antenna in the development of millimeter-wave automotive radar systems.