This paper presents a novel concept for realizing a large-scale subharmonic coherent detector array at 600 GHz. The local oscillator (LO) signal at 300 GHz is distributed through a low-loss 4×4 waveguide-based power distribution network, which is realized by the silicon deep etching technique. The detector and its integrated on-chip antennas, one for LO and one for the radio frequency (RF) signal, are designed based on the TSMC 65 nm CMOS process. Both signals are collected wirelessly and combined first by the antennas, then delivered to the detectors. To achieve a large Field-of-View (FoV), the distance between adjacent unit cells is a multiple of wavelength, forming a sparse array where all the channels are independently operated.