Self-biasing circulators operating at Ka-band utilizing M-type hexagonal ferrites

The authors report on the fabrication and testing of millimeter-wave microstrip/stripline Y-junction circulator operating at K_a band. By exploiting the properties of high-anisotropy magnetic field, external magnetic field requirements are reduced. The design of microstrip/stripline circulators involves calculations of the radius of the ferrite disks and the port suspension angles in terms of the microstrip dielectric constant and saturation magnetization of the ferrite material. In addition, the operation frequency is determined largely by the uniaxial anisotropy field of the barium-strontium hexagonal ferrite