Microstrip resonance isolator

摘要

A microstrip resonance isolator is provided comprising a dielectric waveguide element which is mounted on the top surface of a length of microstrip transmission line dielectric substrate having an electrically conductive ground plane on the bottom surface of the substrate. The waveguide element has a rectangular rod-shaped central section and two oppositely-inclined ramp-shaped sections at the ends of the central section. The dielectric constant of the waveguide element is substantially more than the dielectric constant of the microstrip transmission substrate. A microstrip conductor is provided on the top surface of the substrate from one end thereof to the other end thereof and passes over the top surface of the dielectric waveguide element. A thin, rectangular substrate of hexagonal, grain-oriented ferrite material is mounted on one side of the waveguide element between the ramp-shaped end sections. The ferrite substrate material is given a predetermined uni-directional magnetic orientation in a direction which is parallel to the plane of the side of the waveguide element on which the ferrite substrate is mounted and is substantially perpendicular to the plane of the microstrip dielectric substrate top surface, so that the ferrite substrate and the dielectric waveguide element cooperate to form a dielectric waveguide resonance isolator and the ends of the microstrip conductor act as the terminals of the microstrip isolator.