This thesis addresses the analysis and design of a mid-infrared optical phased array (OPA) based on a germanium-on-silicon (Ge-on-Si) integrated photonic platform operating in the 4–8 µm wavelength range. Such devices are of growing interest for beam steering and sensing applications requiring compact and scalable solutions. The work develops a consistent design framework starting from the accurate modeling of Ge-on-Si waveguides. A calibration procedure is introduced to account for mid-infrared propagation losses in the material model, enabling realistic numerical simulations. Based on this approach, the waveguide geometry is optimized to ensure proper modal confinement and single-mode operation across the operating band.