Narrative Review on Advances in Measurement of Electrical Properties of Materials using Free Space Method

Abstract

The free-space measurement technique is a widely used method for determining the electrical characteristics of materials. The free-space measurement approach had attracted more attention due to the possibility of efficient measurements using higher millimetre-wave and terahertz frequencies. This is primarily due to its ease of use, non-destructive features, and ability to perform reflection and transmission measurements without making physical interaction with the sample. This paper discusses free space material measurement systems, beginning with the various measurement methods available for material characterization, their key concepts, post-processing in determining their properties, and advancing to their use at higher frequencies. In addition, this study discusses dielectric material characterization utilizing the free space approach, with an emphasis on their applicability to higher frequencies. This study also examined the algorithms for conversion methods and the application of lenses in free space material measurement system. Prior to the conclusion, a prospective view on the potential of this free space method was presented.