This article presents a planar 2-dimensional CMOS 288–344 GHz 4x4 channel phased-array receiver (RX) with an antenna pitch of 0.52 λ0. This is the first silicon 2D phased-array RX above 300 GHz known to the authors. The RX implements a third order subharmonic mixer and dual-layer IF interconnect lines. The RX scans over ±40°/±44° in the E- and H-planes respectively, and achieves a single-sideband NF of 26.8 dB. Power consumption is 1.877 W. A 6.4-cm, 307-GHz communication link with the RX chip demonstrated a 1.6-Gb/s data rate with an EVMrms of 10.96% using 16-QAM waveforms.