Extraction of Microwave Properties Using a Single Transmission Line: Application to Carbon Nanopowders Decorated with Magnetic Nanoparticles

Abstract

The microwave properties of carbon-based nanopowders, whether or not they are coated with magnetic nanoparticles, are characterized using a unique approach in this chapter. The microwave characterization of materials is of prime interest for several applications. Dielectric constant, electrical conductivity, and complex magnetic permeability, which are its microwave properties, are derived from tests with a single transmission line acting as the test cell. Successful tests were conducted on two different transmission line geometries. A phenomenological model is used to evaluate the measurement data and fit the conductivity and dielectric constant measurements, giving insight into the powder sample's compacity quality. Additionally, the discovery of a ferromagnetic resonance with a linear dependence on the external DC magnetic field supports the extraction of the permeability.