Spinel-olivine microwave dielectric ceramics with low sintering temperature and high quality factor for 5 GHz wi-fi antennas

• Published in: Applied materials today 2020-12, Vol.21, p.100826, Article 100826
• Main Authors: Xiang, Huaicheng, Kilpijärvi, Joni, Myllymäki, Sami, Yang, Haitao, Fang, Liang, Jantunen, Heli
• Format: Article
• Language: English
• Subjects: 5 ghz patch antenna; Low-temperature cofiring; Microwave dielectric properties; Spinel-olivine ceramics
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2020.100826

•Spinel-olivine composite ceramics of Li2ZnGe3O8-Li2ZnGeO4 were prepared at 800–980 °C by solid-state reaction. At 900 °C, the content of Li2ZnGe3O8 and Li2ZnGeO4 is about 1:1.•The good microwave dielectric properties (εr ~ 8.15, q × f ~ 32,500 GHz, τf ~ −74.8 ppm/ °C) and compatible with the ag electrode revealed that the Spinel-olivine composite ceramics are suitable for manufacturing 5 GHz wi-fi patch antenna through LTCC technology.•A square patch antenna with compact dimensions of 19.62 × 13.29 × 0.8 mm was fabricated. Spinel-olivine composite ceramic gave a S11 of −14 dB and a radiation efficiency of 59% at 5.7 GHz. The patch antenna of spinel-olivine composite ceramic (Li2ZnGe3O8-Li2ZnGeO4) is designed, which can realize power ratio (59%) and S11 of -14 dB at 5.7 GHz. The low sintering temperature (< 960 °C), low relative permittivity (8.15) and good microwave dielectric properties (quality factor ~ 32,500 GHz, resonant frequency temperature coefficient ~ -74.8 ppm/ °C) were obtained for spinel-olivine composite ceramic. Li2ZnGe3O8-Li2ZnGeO4 composite microwave dielectric ceramics were synthesized at 900–980 °C using Li2CO3, ZnO and GeO2, which can co-fire with silver electrodes without chemical reaction. These exceptional characteristics enable high-speed signal transmission application of spinel-olivine composite ceramics (Li2ZnGe3O8-Li2ZnGeO4) in 5 GHz Wi-Fi antennas. The spinel-olivine composite microwave dielectric ceramics (Li2ZnGe3O8-Li2ZnGeO4) were fabrication at the low sintering temperature, and their low relative permittivity and low dielectric loss make them suitable for use in 5 GHz Wi-Fi antennas. [Display omitted]