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The microwave dielectric properties and microstructures of (Mg 0:95 Zn 0:05 )TiO 3 ceramics, prepared by a mixed oxide route, were investigated. The ceramics could be sintered at temperatures as low as 1250 C and their microwave dielectric properties were found to be strongly correlated with sintering temperature. The quality factor (Q Â f ) of (Mg 0:95 Zn 0:05 )TiO 3 increased with temperature up to 1300 C and decreased thereafter. The decrease in Q Â f was coincident with the observed abnormal grain growth. A maximum Q Â f of 264000 GHz associated with an " r of 17.1 and a f of À40:3 ppm/ C was achieved for the samples at 1300 C/4 h. Thus, (Mg 0:95 Zn 0:05 )TiO 3 is proposed as a very promising dielectric material for low-loss microwave applications.

The microwave dielectric properties and the microstructures of (Mg1−xZnx)2TiO4 ceramics prepared by the conventional solid‐state route were investigated. Lattice parameters were also measured for samples with different x. As x increased from 0 to 0.05, the Q×f of the specimen can be promoted from 150 000 GHz to a maximum 275 300 GHz. It also showed a remarkable lowering in the sintering temperature (∼100°C). Ilmenite‐structured (Mg0.95Zn0.05)TiO3 was detected as a second phase. The coexistence of the second phase, however, is not harmful to the dielectric properties of the specimen because it possesses compatible ones. A fine combination of microwave dielectric properties (ɛr∼15.48, Q×f∼275 300 GHz, τf∼−34 ppm/°C) was obtained for (Mg0.95Zn0.05)2TiO4 specimen sintered at 1330°C for 4 h. It is proposed as a very promising dielectric material for low‐loss microwave and millimeter wave applications.

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The microwave dielectric properties and the microstructures of Nd(Zn1/2Ti1/2)O3 (NZT) ceramics prepared by the conventional solid‐state route have been studied. The prepared NZT exhibited a mixture of Zn and Ti showing 1:1 order in the B‐site. The dielectric constant values (ɛr) saturated at 29.1–31.6. The quality factor (Q×f) values of 56 700–170 000 (at 8.5 GHz) can be obtained when the sintering temperatures are in the range of 1300°–1420°C. The temperature coefficient of resonant frequency τf was not sensitive to the sintering temperature. The ɛr value of 31.6, the Q×f value of 170 000 (at 8.5 GHz), and the τf value of −42 ppm/°C were obtained for NZT ceramics sintering at 1330°C for 4 h. For applications of high selective microwave ceramic resonators, filters, and antennas, NZT is proposed as a suitable material candidate.

The microstructures and the microwave dielectric properties of the (1-x)(Mg 0.95 Zn 0.05 )TiO 3 -xSrTiO 3 ceramic system were investigated. (Mg 0.95 Zn 0.05 )TiO 3 possesses high dielectric constant (e r B17.05), high quality factor (Q Â f valueB264 000 at 9 GHz), and negative s f value (À40.31 ppm/1C). In order to achieve a temperature-stable material, SrTiO 3 , having a large positive s f value of 1700 ppm/1C, was added to (Mg 0.95 Zn 0.05 )TiO 3 . Twophase system was confirmed by the X-ray diffraction patterns and the measured lattice parameters. Evaporation of Zn occurred at temperatures higher than 13001C and caused an increase in the dielectric loss of the system. As the x value varies from 0 to 0.1, (1-x)(Mg 0.95 Zn 0.05 )TiO 3 -xSrTiO 3 ceramic system has the dielectric properties as follows: 17.05oe r o26.35, 20 000oQ Â fo264 000, and À41os f o140. By appropriately adjusting the x value in the (1-x)(Mg 0.95 Zn 0.05 )TiO 3 -xSrTiO 3 ceramic system, zero s f value can be achieved. A new microwave dielectric material, 0.96(Mg 0.95 Zn 0.05 )TiO 3 -0.04SrTiO 3 applicable in microwave devices is suggested and possesses the dielectric properties of a dielectric constant e r B20.96, a Q Â f va-lueB135 000 GHz (at 9 GHz), and a s f value B0 ppm/1C. A compact band-pass filter using two open-loop ring resonators with asymmetric tapping feed lines is designed and fabricated using the proposed dielectric to study its performance.

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