The Occurrence of Parasitic Radiation in Transmission-Reflection Material Characterization using a Sandwich Antenna-Sample-Antenna Setup

The occurrence of parasitic radiation through the sample into the free space in a widely used sandwich antenna-sample-antenna (SASA) setup for the transmission-reflection (TR) method based material characterization is investigated for the first time. A simple equivalent circuit (EC) taking into account the losses due to this radiation in order to exclude them as dielectric losses in the measurement procedure is presented. Based on conducted near-field (NF) measurements, the time-averaged Poynting vector has been calculated qualitatively demonstrating the occurrence of the conjectured parasitic radiation. This conclusion is further supported by an independent far-field (FF) measurement.