Low-cost nonplanar microstrip-line ferrite phase shifter utilizing circular polarization

Microwave ferrite phase shifters are primarily used in phased-array antenna systems to electronically steer the antenna beam. Lee and Strahan (1993) at Hughes Aircraft Company (now Raytheon) proposed a low-cost alternative solution to the current ferrite phase shifter designs, namely, a planar ferrite phase shifter based on printed-circuit technology that could theoretically produce circularly polarized waves in the ferrite region. The University of Hawaii (2003) modelled Raytheon´s patented ferrite phase shifter using Ansoft´s High Frequency Structure Simulator (HFSS) software, now capable of simulating the effect of an applied magnetic bias on a B-H nonlinear (ferrite) material. It was found that the horizontal electric-field component was much weaker than the vertical component, resulting in elliptical polarization rather than circular polarization. In an effort to transform the elliptically polarized wave into a circularly polarized wave, the geometry of the Raytheon phase shifter was modified to produce the nonplanar ferrite phase shifter proposed in this paper.