The modeling, design, and optimization of a new substrate integrated waveguide middle-fed series rectangular dielectric resonator antenna array with 45° linear polarization are presented. The implicit space mapping technique is applied for the optimization of the antenna array. A tunable circuit model is built, which serves as the coarse/surrogate mode, and a full-wave solver is used as the fine model. High design and optimization efficiency is demonstrated using an eight-element array. The reflection coefficient of the array antenna is optimized with only two iterations. The experimental data for the eight elements antenna array, operating at the millimeter-wave band (34–36 GHz), are used for the validation of both performance of the design and modeling techniques. The measured radiation pattern demonstrates a broadside beam with a maximum radiated gain of 13.55 dB over an operating impedance bandwidth of 2.2 GHz.