Microwave dielectric properties and frequency-controlled beam scanning application of Nb5+-substituted calcium-magnesium vanadate low-temperature sintered ceramics

Abstract

Beam scanning devices in the X-band allow spatial reorientation of the beam, but this poses challenges for material and device design. To meet such challenges, the development of microwave dielectric materials and the design of special structures are crucial. Here, the microwave dielectric properties of Ca5Mn4V6-xNbxO24 (x = 0.00–0.08) ceramics are systematically investigated by using first-principles calculations and microstructural analysis. The ceramic has the best microwave dielectric properties (εr = 10.92 ± 0.14, Q × f = 50032 ± 1795 GHz (@10.52 GHz), τf = −59.58 ± 3.81 ppm/°C) when x = 0.04 and T = 875 °C. As a concept demonstration for device applications, a frequency-controlled beam scanning device in the X-band is designed by using this ceramic and copper electrode. This device has a beam scanning space of 3.248° (from 27.143° to 32.371°) in the frequency range of 10–11 GHz while maintaining high reflectivity (≥0.6). This function is verified by simulation results for far-field amplitude and far-field phase. This work contributes to the application of microwave dielectric ceramics.