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

A low-cost microwave ferrite phase shifter is proposed in this paper. The phase shifter is comprised of three parallel nonplanar microstrip lines separated from a ground plane by a substrate containing a ferrite rod/slab. The amount of phase shift between the input and output ports is determined by the strength of the magnetic bias field applied to the ferrite. A three-way power divider was designed to feed the microstrip lines with different magnitudes and phases. By combining the effects of the nonplanar geometry and the phase offsets introduced by the feed network, circularly polarized waves can be produced in the ferrite. These waves strongly interact with the biased ferrite resulting in a large phase shift over a short distance-90°/cm based on current simulation results. This device will be best suited for use in high-gain phased-array radar systems.