Work

Ultrahigh- Q Sr 1+ x Y 2O 4+ x ( x= 0.01–0.04) microwave dielectric ceramics for temperature-stable millimeter-wave dielectric resonator antennas

Year: 2023

Type: article

Abstract: Microwave dielectric ceramics should be improved to advance mobile communication technologies further. In this study, we prepared Sr1+xY2O4+x (x = 0–0.04) ceramics with nonstoichiometric Sr2+ ratios based on our previously reported SrY2O4 microwave dielectric ceramic, which has a low dielectric constant and an ultrahigh quality factor (Q value). The ceramic exhibited a 33.6% higher Q-by-frequency (Q×f) value (Q ~12,500) at x = 0.02 than SrY2O4. All Sr1+xY2O4+x (x = 0–0.04) ceramics exhibited pure phase structures, although variations in crystal-plane spacings were observed. The ceramics are mainly composed of Sr-O, Y1-O, and Y2-O octahedra, with the temperature coefficient of the resonant frequency (τf) of the ceramic increasing with Y2-O octahedral distortion. The ceramic comprises uniform grains with a homogeneous elemental distribution, clear grain boundaries, and no obvious cavities at x = 0.02. The Sr1+xY2O4+x (x = 0–0.04) ceramics exhibited good microwave dielectric properties, with optimal performance observed at x = 0.02 (dielectric constant (εr) = 15.41, Q×f = 112,375 GHz, and τƒ = −17.44 ppm/℃). The τf value was reduced to meet the temperature-stability requirements of 5G/6G communication systems by adding CaTiO3, with Sr1.02Y2O4.02+2wt%CaTiO3 exhibiting εr = 16.14, Q×f = 51,004 GHz, and τf = 0 ppm/℃. A dielectric resonator antenna prepared using Sr1.02Y2O4.02+2wt%CaTiO3 exhibited a central frequency of 26.6 GHz, with a corresponding gain and efficiency of 3.66 dBi and 83.14%, respectively. Consequently, Sr1.02Y2O4.02-based dielectric resonator antennas are suitable for use in 5G millimeter-wave band (24.5–27.5 GHz) applications.

Source: Journal of Advanced Ceramics

DOI: 10.26599/jac.2024.9220828