Integrated metal magnetic film coupled line circulators for monolithic microwaveintegrated circuits

A new structure of integrated planar metal magnetic film coupled line (MMFCL) circulators is presented, in which a metal magnetic film is used instead of ferrite materials. Simulation was performed with HFSS based on coupled-mode theory. An insertion loss of 4 dB and isolation of −13.5 dB between S21 and S12 over a frequency band of 3 GHz (from 36.5 to 39.5 GHz) were realised for a three-port MMFCL circulator.