Theoretical and experimental treatment of a microstrip coupled ferrite line circulator

The paper describes a microstrip ferrite coupled line (FCL) junction practically applied as a section of the FCL circulator. Improvements over the earlier models include realisation of the microstrip circuit on the dielectric substrate and placing a ferrite overlay on top of the coupled line of the FCL section. Simulation and measurements show the operation bandwidth from 10 to 15 GHz with isolation and reflection losses better than 10 dB and average insertion losses <2.5 dB.