TDC-220330-20-3.4 is a J-band, four-port waveguide directional coupler that delivers a 20 dB nominal coupling level and 30 dB typical directivity across the full waveguide band from 220 to 330 GHz. The interfaces of the coupler are WR-3.4 waveguides with UG-387/U-M anti-cocking flanges.