The C17-0R506 from Marki Microwave is a low loss directional coupler that operate from 0.5 to 6 GHz. It has a coupling value of 17.5 dB and can handle up to 120 watts of power. The coupler has an insertion loss of 0.4 dB and directivity of 20 dB. It is available in a module with SMA and APC-7 connectors options.
