Analysis of Transmission Properties of Sludge Biochar Composites in the C-Band

In order to pave the way for the widespread use of eco-friendly materials for novel applications, there is a growing need for morphological, mechanical and electrical, and microwave characterization techniques. The measurement of scattering parameters is an accurate technique for the microwave characterization of novel materials, but it requires a number of components, including waveguides, adapters, and so on. The band of measurements is also limited to the working band of the waveguide used. A method of retrieving waveguide scattering parameters from permittivity values is devised. The method is validated with measurements of the scattering parameters in a waveguide. The method is tested with composites based on biochar derived from sewage sludge and a standard epoxy sample. The addition of biochar considerably reduces transmission scattering and is found to be a suitable candidate for filling composite materials.