High-speed, ferrite microwave switch

A microwave circulator utilizing ferrite elements can be converted into a fast-acting microwave switch by placing the ferrite in a pulsed magnetic field. The operation of the circulator may be based on the Faraday rotation phenomenon or on the nonreciprocal phase shift observed in a ferrite-loaded rectangular waveguide. Problems in the design of the microwave structure as well as the electronic driving circuitry are discussed. Various techniques for the reduction of eddy currents in the waveguide are presented and the performance characteristics of various switches are given.