(Ni1/3Nb2/3)4+-Improved High- K Ba3Ti4Nb4O21 Microwave Dielectric Ceramics for Miniaturized All-Ceramic Radomes with 5G Beam-Splitting Function

Inorg Chem. 2024 Mar 4;63(9):4404-4411. doi: 10.1021/acs.inorgchem.4c00043. Epub 2024 Feb 21.

Abstract

With the rapid development of 5G communication technology, microwave dielectric ceramics with high dielectric constants are very conducive to the miniaturization of passive devices. Here, Ba3Ti4-x(Ni1/3Nb2/3)xNb4O21 (BTN ∼ NN, 0.03 ≤ x ≤ 0.15) ceramics with hexagonal phases are synthesized via the solid-phase route. The composite (Ni1/3Nb2/3)4+ ion substitution strategy can substantially improve the microwave dielectric properties of the Ba3Ti4Nb4O21 (BTN) ceramic. The εr and Q × f values depend on the ionicity (Nb-O bonds) and lattice energies (Nb(1)-O3 and Nb(1)-O2(1) bonds). The microwave dielectric properties of the BTN ∼ NN (x = 0.09) ceramic sintered at 1250 °C are εr = 60.3, Q × f = 22073 GHz, and τf = 78.1 ppm/°C. A miniaturized all-ceramic radome (@400 mm × 400 mm × 8 mm) for 5G beam-splitting function is designed and demonstrated using this ceramic. Compared to other radomes designed for other work utilizing low εr, the size of this radome has been reduced by 3/7. The reflection coefficients of the beam splitting function are all 0.73, and the phase shifts are all 360°. This work contributes to the development of miniaturized passive devices from a materials point of view.