Low-Temperature Micropatterning of Thick-Film BaFe12O19 Composites on Semiconductor Substrates for Integrated Millimeter Wave Devices

This paper reports the fabrication and characterization of thick, self-biased hexaferrite magnetic structures patterned on planar substrates for integrated millimeter-wave (mm-wave) device applications. Using all lowtemperature processes, BaFe12O19 micro/nanoparticles (from three different vendors) and polymeric binder (PDMS) are screenprinted into removable molds to form 600-μm-diameter, 144-μm-thick test structures. The crystallography, morphology, and DC magnetic hysteresis curves are evaluated. Methods are shown for imposing magnetic anisotropy in the films. A direct measurement of the RF properties using a coplanar waveguide test structure is performed, showing a ferromagnetic resonance (FMR) frequency of 45.9 GHz with tunability via an external magnetic field.