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Abstract: The microwave dielectric properties of the (1− x)Li2TiO3–xZnO (x =0.1–0.5) ceramic system prepared by mixed oxide route have been investigated. The rock-salt structured (1− x)Li2TiO3–xZnO were characterized by using X-ray diffraction spectra, scanning electron microcopy (SEM). The dielectric properties are strongly dependent on the compositions, the densifications and the microstructures of the specimens. The decrease of Q × f value at high-level ZnO addition (x >0.3) was owing to the intensity of the (002) superstructure reflection decreased and became disordered rock-salt structure. For practical applications, a new microwave dielectric material 0.7Li2TiO3–0.3ZnO is suggested and it possesses a good combination of dielectric properties with an of ∼22.95, a Q × f of ∼99,800GHz (measured at 8.91GHz), and a of ∼0ppm/°C. A low-loss dielectric resonant antenna using aperture-coupled cylindrical dielectric resonant was designed and fabricated using the proposed dielectric to study its performance. [Copyright &y& Elsevier]

Abstract: (Mg1−x Zn x )1.8Ti1.1O4 (x =0.03–1.00) ceramics were prepared via the conventional solid-state method and their dielectric properties were investigated in the microwave frequency region. Formation of solid solutions was confirmed by the X-ray diffraction analysis, the EDX analysis, and the measured lattice parameters. A small amount of Zn substitution for Mg produced a large increase in Q × f due to a high packing fraction as well as a high relative density of the ceramics. By increasing x from 0.00 to 0.06, the Q × f of the specimen could be tremendously improved from 141,000 to a maximum of 210,700GHz (at 10.52GHz), demonstrating an unique potential for low-loss microwave applications. The τ f values were found to retain in the range from −54.2 to −62.3ppm/°C for all compositions because the resultant change of unit cell volume was small. Also, a remarkable lowering of the sintering temperature down to ∼300°C was observed when Mg was totally substituted by Zn, thereby making it possible for low firing applications. [Copyright &y& Elsevier]

Abstract: Low-loss Mg1.8Ti1.1O4 ceramics were prepared by the conventional solid-state route and their microwave dielectric properties were investigated for the first time. The forming of tetragonal-structured Mg1.8Ti1.1O4 main phase associated with a second phase MgTiO3 were confirmed by the X-ray diffraction patterns. However, the presence of the second phase would cause no significant variance in the dielectric properties of the specimen because the second phase properties are very similar to that of the main phase. A fine combination of microwave dielectric properties (ɛ r ∼15.74, Q × f ∼141,000GHz at 10.57GHz, τ f ∼−52.4ppm/°C) was achieved for Mg1.8Ti1.1O4 ceramics sintered at 1450°C for 4h. [Copyright &y& Elsevier]

Abstract: Rock-salt-structured Li2MgTiO4 ceramic was prepared by the conventional mixed oxide route and its microwave dielectric properties were investigated. The microstructures of the ceramics were characterized by SEM. The dielectric properties of the ceramics exhibited a significant dependence on the sintering condition and crystal structure. A new microwave dielectric material, Li2MgTiO4 sintered at 1360°C has a dielectric constant (ɛ r ) of ∼17.25, a Q × f of ∼97,300GHz (where f =9.86GHz, is the resonant frequency) and a τ f of ∼–27.2ppm/°C. The microwave dielectric properties of the ceramic are reported for the first time. [Copyright &y& Elsevier]