Design of a High-Efficiency and -Gain Antenna Using Novel Low-Loss, Temperature-Stable Li2Ti1- x(Cu1/3Nb2/3) x O3 Microwave Dielectric Ceramics

Huan-Huan Guo; Mao-Sen Fu; Di Zhou; Chao Du; Peng-Jian Wang; Li-Xia Pang; Wen-Feng Liu; Antonio Sergio Bezerra Sombra; Jin-Zhan Su

doi:10.1021/acsami.0c18836

Design of a High-Efficiency and -Gain Antenna Using Novel Low-Loss, Temperature-Stable Li₂Ti₁- _x(Cu_1/3Nb_2/3) _x O₃ Microwave Dielectric Ceramics

ACS Appl Mater Interfaces. 2021 Jan 13;13(1):912-923. doi: 10.1021/acsami.0c18836. Epub 2020 Dec 24.

Authors

Huan-Huan Guo¹, Mao-Sen Fu², Di Zhou¹, Chao Du¹, Peng-Jian Wang¹, Li-Xia Pang³, Wen-Feng Liu⁴, Antonio Sergio Bezerra Sombra^{5

6}, Jin-Zhan Su⁷

Affiliations

¹ Key Laboratory of Multifunctional Materials and Structures, Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
² Shaanxi Materials Analysis and Research Center, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, China.
³ Micro-optoelectronic Systems Laboratories, Xi'an Technological University, Xi'an, Shaanxi 710032, China.
⁴ State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
⁵ Telecommunication Engineering Department, Federal University of Ceará (UFC), P.O. Box 6007, Fortaleza, Ceará 60755-640, Brazil.
⁶ Telecommunication and Materials Science and Engineering of Laboratory (LOCEM), Physics Department, Federal University of Ceará (UFC), Pici Campus, P.O. Box 6030, Fortaleza, Ceará 60455-760, Brazil.
⁷ International Research Centre for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.

PMID: 33356114
DOI: 10.1021/acsami.0c18836

Abstract

Microwave dielectric ceramics are vital for filters, dielectric resonators, and dielectric antennas in the 5G era. It was found that the (Cu_1/3Nb_2/3)⁴⁺ substitution can effectively adjust the TCF (temperature coefficient of resonant frequency) of Li₂TiO₃ and simultaneously increase its Q × f (Q and f denote the quality factor and the resonant frequency, respectively) value. Notably, excellent microwave dielectric properties (ε_r (permittivity) ≈ 18.3, Q × f ≈ 77,840 GHz, and TCF ≈ +9.8 ppm/°C) were achieved in the Li₂Ti_0.8(Cu_1/3Nb_2/3)_0.2O₃ (LTCN_0.2) ceramic sintered at 1140 °C. Additionally, the sintering temperature of LTCN_0.2 was reduced to 860 °C by the addition of 3 wt % H₃BO₃, exhibiting superior microwave dielectric properties (ε_r ≈ 21.0, Q × f ≈ 51,940 GHz, and TCF ≈ 1.4 ppm/°C) and being chemically compatible with silver. Moreover, LTCN_0.2 + 3 wt % H₃BO₃ ceramics were designed as a patch antenna and a dielectric resonator antenna, both of which showed high simulated radiation efficiencies (88.4 and 93%) and gains (4.1 and 4.03 dBi) at the center frequencies (2.49 and 10.19 GHz). The LTCN_0.2 + 3 wt % H₃BO₃ materials have promising future application for either 5G mobile communication devices and/or in low-temperature co-fired ceramic technology owing to their high Q, low sintering temperature, small density, and good temperature stability.

Keywords: antennas; low-temperature sintering; microwave dielectric ceramics; phase transition; temperature stabilities.