Low-Loss Microwave Dielectrics Based on the Columbites A²⁺Nb₂O₆ and Perovskites : The Effect of Compositional Variation

Abstract

Due to their high quality factor in the microwave (MW) range the columbites A²⁺Nb₂O₆ and perovskites can find a variety of applications in the MW engineering. However, the attainment of low-microwave-loss structure of the above compounds is rather complicated task, and their MW properties may vary significantly due to the structural inhomogeneity. In this work the effect of slight compositional non-stoichiometry on the microstructure and MW dielectric properties of the columbites A²⁺Nb₂O₆ and perovskites has been studied and will be discussed. The effects of the quality of starting reagents as well as the synthesis conditions were also considered. The non-linear dependence of the Q-factor magnitude on the chemical composition has been found and associated with the evolution of the microstructure.

Keywords:

• Columbites
• Microwave dielectrics
• Perovskites
• Quality factor