A new microwave ceramic with low-permittivity for LTCC applications

✍ Scribed by Qi-Long Zhang; Hui Yang; Hui-Ping Sun

• Book ID: 104022767
• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 768 KB
• Volume: 28
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.07.003

✦ Synopsis

A new low-temperature microwave dielectric ceramic with low-permittivity was found and investigated in the CaO-MgO-SiO 2 -TiO 2 system. Phase constitutes and dielectric properties of (Ca 1-x ,Mg x )SiO 3 (x = 0.1-0.5) ceramics were studied with different x contents, and CaTiO 3 demonstrated an effective compensation in (Ca 1-x ,Mg x )SiO 3 τ f value. The 0.88CaMgSi 2 O 6 -0.12CaTiO 3 compositions show a relatively low-permittivity (∼9.42), high Q × f values up to 52,800 GHz, and near-zero temperature coefficients (5.6 ppm/ • C), which were obtained via sintering at 1300 • C. The addition of ≤2.0 wt% Li 2 CO 3 -V 2 O 5 was very effective in lowering the sintering temperature (T s ), and dense ceramics could be obtained at T s ≤ 900 • C. The addition of Li 2 CO 3 -V 2 O 5 does not induce apparent degradation in the microwave properties. The specimens with 1 wt% Li 2 CO 3 -V 2 O 5 sintered at 880 • C for 2 h shows excellent dielectric properties: ε r = 9.23, Q × f = 46,200 GHz, and τ f = 1.3 ppm/ • C. The low-temperature sintering ceramics powders were suitable for the tape casting process. Also, the material is compatible with Ag electrodes, and therefore, is suitable for LTCC application.