A 2–30 GHz multi-octave planar microwave six-port for reflectometry applications

This paper presents a planar multilayer six-port circuit implementation based on multi-octave directional couplers. The presented six-port circuit is the first published six-port, that is capable of operating in an ultra-boradband frequency range from 2 to 30 GHz. Within this spectrum the six-port allows for the determination of the complex reflexion coefficient through four scalar power measurements. The six-port circuit is based on the quasi-optimal design proposed by Engen. Proper functionality has been verified through measurements of the S-parameters and the calculated q-points.