Electronic Sub-Terahertz VNA Measurement Techniques

Abstract

AbstractMost biomedical applications rely on dielectric constant characterization for sensing and imaging applications; however, two well-known techniques in the sub-THz and THz frequency ranges can be used for this purpose. Both Time-Domain Spectroscopy (TDS) and dielectric characterization using a Vector Network Analyzer (VNA) are widely used in photonics and electronic engineering. Electronics implementations perform better (in terms of output power) than photonics implementations in the sub-THz region. Additionally, electronics technologies provide a more compact, more integrated, and more cost-effective platform. The purpose of this chapter is to describe the fundamental operation and measurement principles of THz VNA setups. The THz VNAs differ from conventional RF/MMW VNAs by an additional hardware configuration for upconverting the frequency (frequency extenders). The later section describes calibration techniques, the first step toward dielectric characterization using a VNA to improve measurement accuracy. Finally, at the conclusion of the chapter, we will present different dielectric characterization methods using sub-THz probes, including horn antenna and waveguide integrated into the VNA system for permittivity estimation of solids and liquids.