Microwave Instruments and Techniques for the Characterisation and Processing of Novel Materials

Novel materials are indispensable for the development of RF technologies in higher frequency bands, and especially for ensuring that the technologies are sustainable. This talk addresses two major lines, along which microwave techniques contribute to the goal: microwave characterisation and microwave-assisted processing. The first part of the talk presents recent progress in the field of instruments and procedures for the laboratory characterisation and fast industrial testing of novel materials in the 1–170GHz frequency band. Specific attention is given to three groups of materials: dielectric substrates and copper foils, fundamental in reducing loss and enhancing efficiency of the emerging 5G and 6G systems; liquids and coolants, essential for reducing or regulating the temperature of HF systems, especially high-performance computers such as those used by AI; energy materials, such as those used for solar cells or battery anodes and cathodes, which facilitate efficient energy conversion and storage. This part of the talk is illustrated with examples of application of novel resonator-based instruments, including: sapphire post resonator or Fabry-Perot Open Resonator for non-destructive characterisation of copper foils (without any need to test circuit manufacturing while rigorously accounting for surface roughness); Q-Choked cavity resonators (allowing multi-modal measurements of thick and high-permittivity samples); and 2D dielectric-resonator scanners (for detecting surface defects and non-uniformities). The second part of the talk presents microwave-assisted techniques for the development and processing of materials: from the manufacturing of cellulose-based biocomposites for EMC applications, to the recycling of electronic waste by microwave pyrolysis. A variety of examples are brought to the attention of the workshop attendees based on the works of non-IEEE societies (IMPI and AMPERE), aiming to enhance intersociety collaborations in the field of novel materials and systems.