Novel Method to Achieve Temperature-Stable Microwave Dielectric Ceramics: A Case in the Fergusonite-Structured NdNbO4 System

Di Zhou; Ling Zhang; Di-Ming Xu; Feng Qiao; Xiaogang Yao; Huixing Lin; Wenfeng Liu; Li-Xia Pang; Fayaz Hussain; Moustafa Adel Darwish; Tao Zhou; Yawei Chen; Qixin Liang; Meirong Zhang; Ian M Reaney

doi:10.1021/acsami.2c23180

Novel Method to Achieve Temperature-Stable Microwave Dielectric Ceramics: A Case in the Fergusonite-Structured NdNbO₄ System

ACS Appl Mater Interfaces. 2023 Apr 19;15(15):19129-19136. doi: 10.1021/acsami.2c23180. Epub 2023 Apr 5.

Authors

Di Zhou¹, Ling Zhang¹, Di-Ming Xu¹, Feng Qiao¹, Xiaogang Yao², Huixing Lin², Wenfeng Liu³, Li-Xia Pang⁴, Fayaz Hussain⁵, Moustafa Adel Darwish⁶, Tao Zhou⁷, Yawei Chen⁸, Qixin Liang⁸, Meirong Zhang⁸, Ian M Reaney⁹

Affiliations

¹ Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
² Key Laboratory of Inorganic Functional Material and Device, Shanghai Institute of Ceramics Chinese Academy of Sciences, Shanghai 200050, China.
³ State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.
⁴ Micro-Optoelectronic Systems Laboratories, Xi'an Technological University, Xi'an 710032, Shaanxi, China.
⁵ Department of Materials Engineering, NED University of Engineering & Technology, Karachi 75270, Pakistan.
⁶ Physics Department, Faculty of Science, Tanta University, Al-Geish St., Tanta 31527, Egypt.
⁷ School of Electronic and Information Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
⁸ Shenzhen Microgate Technology Co., Ltd., Shen Zhen 518118, Guang Dong, China.
⁹ Functional Materials and Devices Group, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, U.K.

PMID: 37018740
DOI: 10.1021/acsami.2c23180

Abstract

Microwave dielectric ceramics with permittivity (ε_r) ∼ 20 play an important role in massive multiple-input multiple-output (MIMO) technology in 5G. Although fergusonite-structured materials with low dielectric loss are good candidates for 5G application, tuning the temperature coefficient of resonant frequency (TCF) remains a problem. In the present work, smaller V⁵⁺ ions (r_V = 0.355 Å, with coordination number (CN) = 4) were substituted for Nb⁵⁺ (r_Nb = 0.48 Å with CN = 4) in the Nd(Nb_1-xV_x)O₄ ceramics, which, according to in situ X-ray diffraction data, lowered the fergusonite-to-scheelite phase transition (T_F-S) to 400 °C for x = 0.2. The thermal expansion coefficient (α_L) of the high-temperature scheelite phase was +11 ppm/°C, whereas for the low-temperature fergusonite phase, it was + 14 < α_L < + 15 ppm/°C. The abrupt change in α_L, the associated negative temperature coefficient of permittivity (τ_ε), and the minimum value of ε_r at T_F-S resulted in a near-zero TCF ∼ (+7.8 ppm/°C) for Nd(Nb_0.8V_0.2)O₄ (ε_r ∼ 18.6 and Qf ∼ 70,100 GHz). A method to design near-zero TCF compositions based on modulation of τ_ε and α_L at T_F-S is thus demonstrated that may also be extended to other fergusonite systems.

Keywords: dielectric resonator; fergusonite; microwave dielectric ceramics; scheelite; temperature coefficient of resonant frequency.