Ternary system rock salt Li3NbO4–Li2TiO3–MgO microwave dielectric ceramics with low loss for resonator antenna applications

Abstract

A novel type of Li3NbO4–Li2TiO3-xMgO (LLMx, x = 1–5) ceramics were prepared using the solid-state reaction method. When the sintering temperature is between 1180 °C and 1300 °C, the solid solution ceramics with cubic rock salt structure are obtained. As the MgO content increases, the εr value decreases, the τf value is basically constant, and Q×f exhibits ideal dielectric properties at x = 4 (εr = 15.26, Q×f = 119,456 GHz (f = 9.97 GHz), τf = −35.9 ppm/°C). The Raman spectrum analysis was used to examine and understand the vibration mode and intrinsic mechanism of dielectric properties in ceramics. Additionally, a dielectric resonant antenna based on LLM4 ceramic is fabricated with a resonant frequency of 7.23 GHz (|S11| = −45.6 dB), a higher gain and broadband width of 501 MHz.