By combining the effects of the nonplanar geometry and the phase offsets introduced by the feed network, circularly polarized waves are produced in the ferrite material that cause the microwave signal to experience a greater phase shift over a shorter distance—88°/cm based on current simulation results shown in Fig. 3—than can be obtained from a linearly polarized microwave signal.
Current work is underway to investigate the effect of placing a metal bias coil of varying dimensions around the ferrite phase shifter, since this is the most common and practical way for biasing the ferrite material. Also, the ferrite phase shifter model is being scaled down and may be redesigned to operate at higher frequencies (e.g.10-16 GHz).
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Fig. 2. Geometry of the complete ferrite phase shifter including the power divider/combiner (feed networks). These networks provide the phase offsets between the microstrip lines, thus aiding in the creation of circularly polarized waves in the rectangular ferrite slab.
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Fig.
3. Phase shift as a function of the
magnitude of the applied magnetic
bias field. By varying the bias from
0 to 2000 Oe, a phase shift of 672° was obtained along the length (7.6 cm) of the ferrite slab seen in Fig. 2. This equates to 88°/cm of phase shift.
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DELIVERABLES:
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Low-cost, compact, microwave ferrite phase shifter models based on printed-circuit technology |
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Optimal feed network and bias coil designs |
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User-specified frequency of operation between 1 to 15 GHz |
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HFSS project files, including 3-D models, material & boundary assignments, source definitions, and simulation results (S-parameters & field solutions)
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Prototypes of select ferrite phase shifters that have been successfully modeled in HFSS |
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