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

Abstract

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.