A Novel Waveguide-Based Test Kit for Material Characterization Over Temperature

This paper proposes a novel waveguide-based test kit for conveniently characterizing the constitutive constants of materials over temperature. Different from conventional multiple-part dual-chambered waveguide test kits, the proposed one has only a single waveguide chamber, where the coaxial-to-waveguide and the sample sections are processed together in one piece. Samples are inserted through a slot open on the broad-wall of the kit. No repetitive waveguide calibrations are needed in a temperature measurement, in contrast, a one-time coaxial calibration with online de-embeddings adjust the reference plane and eliminate the thermal drift due to temperature variation. In addition, the proposed kit allows for sample replacement without troublesome waveguide disassembly and reassembly. Two X-band prototypes for room temperature and high temperature are realized by 3-D printing and validated numerically.