Branch Guide Directional Couplers from the Flann Series 140 are particularly suited to applications where multihole couplers cannot be accommodated or tighter coupling values than those achievable from cross guide couplers are required.

Models are available in both 3 and 4 port configurations and standard coupling values are 3 dB, 6 dB and 10 dB. Couplers operating over the full waveguide band are available but for optimum coupling and directivity performance we recommend that the operating frequency range is limited to 25% of the full waveguide band. Please state the operating frequency range required when ordering.


  • Directivity > 40 dB – a new industry standard
  • Flat Coupling Response
  • Models up to 40 GHz
  • Coupling values from 10 dB to 50 dB