Improved Co-substituted zinc vanadate ceramics based on LTCC for enhanced polarization converters

A novel low-loss and low-sintering temperature Zn3-xCox(VO4)(2) (ZCVO) (x = 0.25) ceramic for enhanced polarization converters is developed by solid-state reaction methodology. This ceramic has excellent mi-crowave dielectric properties (epsilon(r) = 13.6, Qxf = 32173 GHz (@10.1 GHz),tau(f)= -74.5 ppm/degrees C) and good chemical compatibility with Ag. According to microstructural analysis, Raman spectroscopy, and first-principles calculations, it is revealed that an appropriate amount of Co2+ substitution can enhance the density, regulate the dielectric constant (epsilon(r)), and improve the Qxf and tau(r) values. Based on this ceramic, an enhanced polar-ization converter is designed. The maximum efficiency is as high as 90.38%. And the performance of this polarization converter can be regulated by the epsilon(r) and dielectric loss of ZCVO ceramics. The mechanism and function of the polarization converter are revealed according to the electric field strength, current direction, and far-field pattern. This work expands the application of microwave dielectric ceramics. (C) 2022 Elsevier B.V. All rights reserved.