We propose a modularized architecture of a large-scale optical phased array (OPA) on a silicon on insulator (SOI) platform, using electro-optical (EO) pixels. Each pixel contains a directional coupler, a micro-ring phase shifter, and a grating optical antenna, on a compact configuration of area 50 μm × 50 μm, with optical and electrical interconnections. Moreover, we present an exemplary blueprint of an OPA consisting of 32 × 32 EO pixels, which sets the width of the main lobe as 0.04° × 0.04° and the field of view as 1.78°. By applying an over-coupled condition, the modulation efficiency and the accompanying intensity modulation are balanced, thus, the OPA performance is not severely degraded. The discussion on the fabrication tolerance shows that the proposed architecture is robust and feasible regarding the state-of-the-art fabrication process, and the performance of the main lobe width and field of view can be further optimized by a larger system size and smaller pixel size. Furthermore, the complexity of interconnections linearly depends on the number of rows and columns, making it highly scalable.