Dielectric response of ANb <sub>2</sub>O <sub>6</sub> (A = Zn, Co, Mn, Ni) columbite niobates: From microwave to terahertz
Weijia Luo, Shun Wang, Siyong Zheng, Jining Li, Menglong Wang, Yongzheng Wen, Lingxia Li, Ji Zhou
Abstract
In the upcoming 6-generation (6G) revolution, the achievement of low power consumption has become a key objective in research concerning terahertz devices. As an important component of passive devices, there are very few low-loss dielectric ceramics in the terahertz range. To elucidate the mechanism of loss and promote the application of microwave dielectric ceramics for the future 6G technology (covering microwave and terahertz <a href="https://ieeexplore.ieee.org/abstract/document/1643614/">frequencies</a>), the terahertz responses of ANb<sub>2</sub>O<sub>6</sub> (A = Zn, Co, Mn, Ni) columbite niobates were studied. The influences of magnetic loss on the Q<em>f</em> values in the microwave range with different transition metal ions in the A-site were reasonably analyzed. Moreover, due to the weakened magnetic relaxation properties in the terahertz range, the samples all exhibited low loss and approximately transparency, especially MnNb<sub>2</sub>O<sub>6</sub> and NiNb<sub>2</sub>O<sub>6 </sub>(tanδ < 0.01 and absorption coefficient < 10 cm<sup>-1</sup> below 1.2 THz), which subverted the definition of traditional low-loss microwave dielectric ceramics. Ultimately, based on Mie theory, we designed a prototypical broadband metamaterial reflector to validate the applicability of the ANb<sub>2</sub>O<sub>6</sub> system in the terahertz band, which is highly important for the development of terahertz ceramic-based passive devices.