A Twin Toroid Ferrite Phase Shifter

Ferrite phase shift and control components designed with low reluctance magnetic bias circuits help to reduce space, weight and energy consumption in microwave systems. Avoiding air-gaps is essential and one suitable geometrical arrangement is the toroidal shaped ferrite positioned inside a rectangular waveguide. A finite element method is presented to model the nonuniform magnetization and partially magnetized state of this type of phase shifter. Using a viscous plastic processing (VPP) method, homogeneous ferrite toroids are fabricated and a twin toroidal phase shifter is designed, assembled and tested. The insertion loss was less than 1 dB over the 9.5 GHz to 10.3 GHz band and return loss of 20 dB was achievable. The phase shift calculation agrees to within 10% of the measured values.