A STRAIN ENGINEERED VOLTAGE TUNABLE MILLIMETER-WAVE FERRITE PHASE SHIFTER

A 50-GHz electric field tunable ferrite-piezoelectric phase shifter based on a bilayer of single crystal M-type hexagonal barium ferrite (BaM) and lead zirconate titanate (PZT) is discussed. A dc voltage applied to PET results in a piezoelectric strain that manifests as an anisotropy field in BaM. A change in the voltage applied to PZT gives rise to variations in the anisotropy field and permeability of BaM and, therefore, a differential phase shift. A phase shift of 45 is measured when the voltage is increased from 0 to 400 V across a 0.5-mm thick PZT. Theoretical estimates of the phase shift are in agreement with the data. (C) 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:261-264, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25725