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High‐dielectric‐constant and low‐loss ceramics in the (1−x)Ca4MgNb2TiO12–xCaTiO3 system have been prepared by the conventional solid‐state route. The forming of complete (1−x)Ca4MgNb2TiO12–xCaTiO3 solid solutions were confirmed by the X‐ray diffraction pattern analysis and the measured lattice parameters, which linearly varied from a=5.5478 Å, b=7.7710 Å, and c=5.4543 Å for x=0.1 to a=5.4718 Å, b=7.6799 Å, and c=5.4262 Å for x=0.9. By increasing x, not only could the τf of the ceramics be turned to a near‐zero value (∼−6.9 ppm/°C) at x=0.3, a substantial Q×f (∼20 200 GHz) and ɛr (∼43.88) could also be achieved simultaneously.

The microwave dielectric properties of (1-x)Mg 1.8 Ti 1.1 O 4 -xCaTiO 3 ceramics prepared by the mixed oxide route have been investigated. Spinel-structured Mg 1.8 Ti 1.1 O 4 , ilmenite-structured MgTiO 3 and perovskite-structured CaTiO 3 were coexisted and the three-phases system was confined by X-ray diffraction patterns, EDX analysis and it also leads to near-zero τ f . The microstructures of the ceramics were characterized by SEM. The microwave dielectric properties of the ceramics can be effectively controlled by varying the x value. For practical applications, a fine combination of microwave dielectric properties (ε r~ 19.61, Qf~ 72,700 GHz at 9.03 GHz, τ f ~ -3.7 ppm/°C) was achieved for 0.91Mg 1.8 Ti 1.1 O 4 -0.09CaTiO 3 ceramics sintered at 1330 °C for 4 h, which makes it is a very promising candidate material for applications in dielectric resonator antenna. A new triple-band dielectric resonator antenna fed by a coplanar waveguide is presented. The proposed antenna, composed of a high permittivity dielectric resonator and printed on FR4 substrate, is fed by a 50 Ω coplanar waveguide transmission line. In order to achieve wideband applications, the antenna with two parasitic inverted-L strip is demonstrated to generate two resonant frequencies covering 3.5 and 5.2 GHz. The measured results show that the antenna covers the frequency bands 2.30-2.72, 3.45-3.61, and 5.05-6.23 GHz with less than -10 dB of S 11 . The frequency response of the simulation results shows good agreement with the measured data. Good antenna gain, radiation efficiency and radiation patterns of the proposed antenna have also been observed across the operation band. Details of the proposed antenna design and experimental results are presented and discussed.