Millimeter Wave Signal Limiter.

A millimeter wave planar slot excited guide ferrite power limiter comprising a length of dielectric transmission line or waveguide for millimeter wave frequencies located on a relatively thin conductive ground plane, forming thereby an image guide. The ground plane includes a plurality of selectively positioned slots along the length of the ground plane under the dielectric waveguide in which bodies of high anisotropy uniaxial barium ferrite material are placed and which collectively act as a passive ferrite power limiter when biased by an externally applied biasing magnetic field. A biasing magnetic field is provided by a pair of rare earth permanent magnetic located along the sides of the image guide perpendicular to the orientation of the RF magnetic fields of the signal propagating down the dielectric waveguide. This leaves the top surface of the image dielectric guide accessible for other integrated circuit fabrication.