Microwave dielectric properties of temperature‐stable zircon‐type (Bi, Ce)VO₄ solid solution ceramics

Abstract

In the (Bi1 − xCex)VO4 (0 ≤ x ≤ 1) system, we found that the (Bi1 − xCex)VO4 (0 ≤ x ≤ 0.1) belongs to the monoclinic scheelite phase and the (Bi1 − xCex)VO4 (0.7 ≤ x ≤ 1) belongs to the tetragonal zircon phase, while the (Bi1 − xCex)VO4 (0.1 < x < 0.7) belongs to the mixed phases of both monoclinic scheelite and tetragonal zircon structure. Interestingly, two components with near‐zero temperature coefficient of resonant frequency (TCF) appeared in this system. In our previous work, a near‐zero TCF of ~+15 ppm/°C was obtained in a (Bi0.75Ce0.25)VO4 ceramic with a permittivity (εr) of ~47.9 and a Qf (Q = quality factor = 1/dielectric loss; f = resonant frequency) value of ~18 000 GHz (at 7.6 GHz). Furthermore, in the present work, another temperature‐stable microwave dielectric ceramic was obtained in (Bi0.05Ce0.95)VO4 composition sintered at 950°C and exhibits good microwave dielectric properties with a εr of ~11.9, a Qf of ~22 360 GHz (at 10.6 GHz), and a near‐zero TCF of ~+6.6 ppm/°C. The results indicate that this system might be an interesting candidate for microwave device applications.

Crystal structure, phase compositions, and microwave dielectric properties of malayaite‐type Ca1−xSrxSnSiO5 ceramics

“…Generally, τ f values are determined by the temperature coefficient of the dielectric constant (τ ε ) in the single-phase area, and τ ε was calculated using Formulas (14) and (15). [30][31][32][33] where α is a constant of about 10 ppm/°C for ceramics, α m and V represent the polarizability and volume, respectively. Hence, τ f values depend mainly on τ ε .…”

“…Zhou Di et al reported that the sum of the second and third terms in the square brackets of Formula (15) is a constant (approximately 6 ppm/°C) and that τ ε values are primarily controlled by the first terms (approximately -1 ~ -10 ppm/°C), which represent the direct dependence of polarizability on temperature. 32 Therefore, τ ε is determined by crystal structure, such as restoring forces acting on the ions, 34 and restoring forces are positively related to octahedral distortions. 35 The τ f values of Ca 1−x Sr x SnSiO 5 (0 ≤ x ≤ 0.15) ceramics could be attributed to the SnO 6 octahedral distortion.…”

Phase evolution, crystal structure, and microwave dielectric properties of gillespite‐type ceramics

“…Wireless communication is largely furthered by 5G technologies with decades of development. Microwave dielectric ceramics have been widely applied in wireless communication systems, such as dielectric resonator, filter, duplexers, and antenna 1‐3 . For 5G wireless communication, high transmission speed (low latency) for devices is more important than miniaturization 4‐6 .…”

Effects of (Mg1/3Sb2/3)4+ Substitution on the Structure and Microwave Dielectric Properties of Ce2Zr3x(Mg1/3Sb2/3)3-3x(MoO4)9 Ceramics

“…Microwave dielectric ceramics have sprung up in the communication industry and received widely attention. It is required to have a high quality factor (Q×f), a moderate dielectric constant (εr) and a near-zero temperature coefficient of resonant frequency (τf) to meet the demands of application [1][2][3][4]. Recently, researchers focused on novel microwave dielectric ceramics [5][6][7].…”