A 60 GHz Dual-Mode Ferrite Phase Shifter

Projected system needs continue to indicate a future requirement for phase shifters at millimeter-wave frequencies. The current state-of-the-art at these frequencies clearly favors ferrite type phase shifters over competing approaches. The two geometries that have been mainly considered for latching ferrite units are: (a) the axial toroid, transverse bias field, nonreciprocal type, and, (b) the dual-mode, longitudinal bias field, reciprocal type. The dual-mode type has a very simple r-f waveguide cross-section compared with the axial toroid type, and thus offers the possibility of easier and cheaper fabrication to necessary tolerances compared with the axial toroid type.