Temperature characterization of high-Q resonators of different materials for mm-wave indoor localization tag landmarks

This paper discusses a temperature-dependent characterization of deep reactive ion-etched 10 kO cm high-resistive silicon (DRIE HR-Si), 3D printed alumina (Al2O3) and milled Rogers RT/Duroid® 6010.2LM. The characterization is performed by measuring high-Q photonic crystal resonator samples in W-band and the measurements are taken from 30∘C to 115∘C. HR-Si is the material with the lowest losses at room temperature. However, its losses increase with temperature and become higher than 3D printed alumina at 75°C, reducing the radar cross-section and maximum readout range of chipless wireless RFID tags integrating several of these resonators. These results demonstrate that, while HR-Si performance is higher for the usual temperatures achieved in an indoor localization scenario, 3D printed alumina is more suitable if a temperature-stable response is needed or if the tags need to operate at high temperatures, such as in case of fire.