Correlation between crystal structure and enhanced microwave dielectric characteristics of wolframite-structure Mg0.5Zr0.5NbO4 ceramics

The lattice vibration and microwave dielectric properties of BaZnP2−xNbxO7 ceramics for microwave substrates

“…The P–O–P stretching modes (700–1000 cm −1 ) were also observed at lower frequencies than those of terminal PO 3 (1100–1230 cm −1 ). The decrease in the intensity was caused by the reducing content of the BaZnP 2 O 7 as the Nb 5+ substitution increases, and the new peak at ∼899 cm −1 is related to the Nb–O symmetric vibrations (A g ) 34,35 . The vibration modes of the other emerging peaks may also be attributed to the second phase.…”

“…The decrease in the intensity was caused by the reducing content of the BaZnP 2 O 7 as the Nb 5+ substitution increases, and the new peak at ∼899 cm −1 is related to the Nb-O symmetric vibrations (A g ). 34,35 The vibration modes of the other emerging peaks may also be attributed to the second phase. Figure 4E presents a schematic diagram of the symmetric stretching (v s ), antisymmetric stretching (v as ), and scissor bending (δ) vibrations of the PO 3 and P-O-P groups.…”

Ceramic compositions for 5G devices containing niobium: A survey

“…The ε r value was found to be related to Nb‐O bond ionicity, and Qxf was dominated by the lattice energy and Nb‐O bond energy. The ceramics sintered at 1350°C/4 h showed ε r = 28.6, Qxf = 82 000 GHz, and τ f = −47 ppm/°C 88 …”

Mechanism of ionic polarizability, bond valence, and crystal structure on the microwave dielectric properties of disordered Li10MTi13O32 (M = Zn, Mg) spinels

“…Microwave dielectric ceramics for 5G applications need to have a low relative permittivity ( ε r ) for modulating signal delay, a high quality factor ( Q × f ) to suppress signal attenuation, and a near-zero temperature coefficient of resonance frequency ( τ f ) to ensure device stability in high-temperature environments. 1–6…”

“…Microwave dielectric ceramics for 5G applications need to have a low relative permittivity (e r ) for modulating signal delay, a high quality factor (Q Â f) to suppress signal attenuation, and a near-zero temperature coefficient of resonance frequency (t f ) to ensure device stability in high-temperature environments. [1][2][3][4][5][6] Microwave dielectric ceramics with a spinel structure (AB 2 O 4 ), such as MgAl 2 O 4 , [7][8][9] and Mg 2 TiO 4 , 10 have been reported to possess a relatively low e r and a high Q Â f. In order to overcome the high sintering temperature, t f is not close to zero for traditional spinels, so a large number of Li-containing spinels have been reported, such as Li 2 ATi 3 O 8 (A = Zn, Mg), 11,12 LiGa 5 O 8 , 13,14 Li 2 Zn 3 Ti 4 O 12 , 15 and Li 4 Ti 5 O 12 . [16][17][18] Concerning the Li 2 O-AO-TiO 2 (A = Zn, Mg) systems, recent studies have focused on the characterization and microwave dielectric properties of two ordered ceramics of Li 2 ZnTi 3 O 8 (e r = 25.6-26.2, Q Â f = 62 000-72 000 GHz, and t f = À15 to À11.2 ppm per 1C) and Li 2 MgTi 3 O 8 (e r = 20.2, Q Â f = 42 000 GHz, and t f = +3.2 ppm per 1C), but the microwave dielectric properties of disordered spinel ceramics have rarely been reported.…”