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With the emergence of 5G–6G communication technology, the miniaturization and integration of electronic components are crucial. Ba3Ti4Nb4O21 (BTN) ceramics with hexagonal structures have attracted special attention due to their high dielectric constant, which shows greater application potential in communication base stations and dielectric resonators. However, its high sintering temperature and low‐quality factors also greatly limit the application field. In this paper, boric acid (H3BO3) as a dopant, was used to investigate the influence on the structure, microstructure, Raman spectrum, and microwave properties for Ba2.92Cu0.08(Zn1/3Nb2/3)2Ti2Nb4O21 (BCZTN)‐xHB (0.25≤x≤1.25 wt%) ceramics. The results reflected that H3BO3 was an effective additive, which could promote ceramic densification, accelerate grain growth and uniform distribution, and enhance its microwave performance. Among them, high densification was 93.92 ± 0.35%, and the Q × f value ∼16981 ± 340 GHz at x = 0.75, was more than 2∼3 times higher than other BTN‐based ceramics. Superior microwave dielectric properties were achieved for 0.75 wt% H3BO3‐doped BCZTN ceramic sintered at 900°C: εr∼42.35 ± 0.48, Q×f∼16981 ± 340 GHz, and τf∼40.02 ± 1.43 ppm/°C. More encouragingly, BCZTN‐0.75HB ceramic did not chemically react with Ag, which suggested that it had the potential to be a candidate material for low‐temperature co‐fired ceramics base station communication devices. [ABSTRACT FROM AUTHOR]

Low‐temperature‐sintered Ni0.5Cu0.125Zn0.375Fe1.98O4 ferrites co‐added with x wt% (x = 0.00‐0.25 wt%) La2O3 and 0.25 wt% Bi2O3 were successfully prepared via conventional solid‐phase reaction method. The phase composition, microstructure, magnetic properties, and especially power loss variation of the samples were systematically studied. The results showed that all samples possessed a single spinel phase structure at a sintering temperature of 900°C, exhibiting high degree of densification and uniform grains. The appropriate amount of La2O3 additive improved the saturation flux density and permeability of NiCuZn ferrites, simultaneously reducing the coercivity and power loss. The maximum permeability and the lowest power loss were achieved at x = 0.15 wt%. The corresponding sample had the homogeneous microstructure and excellent magnetic properties, being a promising low‐temperature co‐fired ferrite candidate for magnetic power components. [ABSTRACT FROM AUTHOR]

A series of Ba1.5Sr1.5Co2+xZrxFe24‐2xO41 hexaferrites (x = 0.00, 0.01, 0.03, 0.05, 0.07, and 0.09) were successfully prepared by the conventional solid‐state reaction method. It was found that as the Co2+ and Zr4+ ions entered the hexaferrite structure, the lattice parameters increased, whereas the relative density increased when x = 0.00‐0.03 and then decreased. A suitable amount of substitution increased the DC resistivity, reduced the magnetic and dielectric losses, and made the μ′$\mu ^{\prime}$ and ε′$\varepsilon ^{\prime}$ closer to each other. At x = 0.03, the relative density and DC resistivity of the samples reached their maxim. Besides, both the magnetic and dielectric losses were lowest within the frequency range of 10 MHz‐1 GHz. Meanwhile, the hexaferrite was impedance matched to free space, and the miniaturization factor was about 15. Therefore, this low‐loss ferrite with almost equal permeability and permittivity could be meaningful for antenna miniaturization and high‐frequency applications. [ABSTRACT FROM AUTHOR]

The BaZnP2−xNbxO7 microwave dielectric ceramics were prepared by solid‐state reaction method to investigate the impact of Nb5+ on the composition, microstructure, and vibrational properties, as well as sintering characteristics and microwave dielectric properties. The solubility of Nb5+ in the BaZnP2−xNbxO7 lattice was limited. A moderate amount of Nb5+ substitution could promote the densification process. The vibrational characteristics of the BaZnP2O7 ceramics were first studied by performing experimental and theoretical Raman and infrared spectroscopy measurements in this work, and their relationship with the microwave dielectric properties was studied. The acquired results showed that (Ⅰ) εr was influenced by both the density and the second phase; (Ⅱ) the density and full width at half maximum of the Raman vibrational peak played a critical role in affecting the Q × f values. The BaZnP2−xNbxO7 samples sintered at 925°C exhibited the outstanding microwave dielectric properties with x = 0.02: εr = 7.98, Q × f = 60 615 GHz (tan δ = 2.18 × 10−4; f = 13.21 GHz) and τf = −52.93 ppm/°C (ρbulk = 4.03 g/cm3; ρr = 92.69%). The proposed ceramic is expected to be used in microwave substrates. [ABSTRACT FROM AUTHOR]

The bond characteristics, Raman spectroscopy, and microwave dielectric properties of Zn3‐xLi2x(BO3)2 ceramics prepared by solid‐state reaction method were investigated. According to the complex chemical bond theory, the bond ionicity and lattice energy of the B–O bond were proved to contributed more to the electric polarization and phase structure stability than that of A‐site bond. Thus, the B–O bond had a dominant effect on the dielectric constant and Q × f values. The optimization of the τf value can be attributed to the bond valence. Moreover, the shift and full width at half maximum of the Raman peak were closely related to the dielectric constant and Q × f values, respectively. On the whole, Li+ substitution contributed greatly to improve the temperature stability and reducing the dielectric loss of Zn3‐xLi2x(BO3)2 ceramics. Additionally, Zn2.99Li0.02(BO3)2 ceramics sintered at 850 °C exhibited satisfactory microwave dielectric properties of εr=6.59, Q × f=122,030 GHz, τf=−76.9 ppm/°C, and had good chemical compatibility with silver. [ABSTRACT FROM AUTHOR]