Microwave and Millimeter Wave Ferromagnetic Absorption of Nanoferrites

Abstract

Complex dielectric permittivity and magnetic permeability of several commercially available nanoferrites have been studied over a broad microwave and millimeter wave frequency range. Nano-sized barium, strontium, copper, zinc, nickel substituted iron oxide powders with different lattice structures are investigated. A transmission-reflection based in-waveguide technique that employs a vector network analyzer was used to determine the scattering parameters for each sample in two microwave bands (18-40 GHz). A free space quasi-optical spectrometer energized by backward wave oscillators was used to acquire the transmittance spectra in the millimeter wave frequency range (30-120 GHz). Relatively broad and sharp ferromagnetic resonance of hexagonal barium ferrite and strontium ferrite are observed in millimeter wave frequency range. The ferromagnetic resonance peak for nano-sized hexagonal ferrite powder material moves to lower frequencies compared to micro-sized and solid hexagonal ferrites. An X-ray diffraction measurement is performed on these hexagonal ferrites to understand the magnetic behavior and the structure.

Characterization of nanostructure ferrite material on gallium nitride on SiC substrate for millimeter wave integrated circuit

“…7 The measurement of complex permittivity and permeability spectra of various samples has been implemented and presented by several researchers. [8][9][10] The source of this quasi-optical spectrometer is three high vacuum, high power Backward Wave Oscillators (BWO) tunable in Q, V, and W bands, respectively. These three bands cover a frequency range from 30 to 120 GHz.…”

Barium Ferrite/Carbon Nanotube Nanocomposites for Millimeter‐Wave Electromagnetic Shielding Enhanced by Ferromagnetic Resonance Absorption

“…Existing characterization methods include commercially available hardware and software modules for VNAs that can yield permittivity, permeability, and loss tangents, [ 12 ] but characterization also be performed manually through algorithms utilizing the measured S parameters of loaded transmission lines. These algorithms include Baker–Jarvis [ 13 ] and Nicolson–Ross–Weir (NRW) [ 6 ] among others. In this work, parameter extraction is performed using the NRW method due to its compatibility with the measurement method and its simplicity in implementation, i.e., no additional hardware/software needed.…”