The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

Abstract

The explosive process of 5G communication evokes the urgent demand of miniaturized and integrated dielectric ceramics filter. It is a pressing need to advance the development of dielectric ceramics utilization of emerging technology to design new materials and understand the polarization mechanism. This review provides the summary of the study of microwave dielectric ceramics (MWDCs) sintered higher than 1000 from 2010 up to now, °C with the purpose of taking a broad and historical view of these ceramics and illustrating research directions. To date, researchers endeavor to explain the structure-property relationship of ceramics with multitude of approaches and design a new formula or strategy to obtain excellent microwave dielectric properties. There are variety of factors that impact the permittivity, dielectric loss, and temperature stability of dielectric materials, covering intrinsic and extrinsic factors. Many of these factors are often intertwined, which can complicate new dielectric material discovery and the mechanism investigation. Because of the various ceramics systems, pseudo phase diagram was used to classify the dielectric materials based on the composition. In this review, the ceramics were firstly divided into ternary systems, and then brief description of the experimental probes and complementary theoretical methods that have been used to discern the intrinsic polarization mechanisms and the origin of intrinsic loss was mentioned. Finally, some perspectives on the future outlook for high-temperature MWDCs were offered based on the synthesis method, characterization techniques, and significant theory developments.

Principal element design of garnets to access structure stability and excellent microwave dielectric properties

“…In general, the microwave dielectric performances of the specimen are influenced by both internal (mainly ionic polarizability and crystal structure) and extrinsic factors (grain boundary, density, secondary phase, etc.) 1,2,25 . Based on the previous phase composition, microstructure, and density analysis, the influence of external elements could be ignored due to the absence of the second phase, compact microstructure with low porosity, and similar average grain sizes.…”

“…The rapid development of Internet of Things, intelligent transportation systems, and fifth‐generation (5G) communication technologies has sparked increased interest in microwave dielectric ceramics research in recent years 1,2 . The three basic and important parameters of microwave dielectric materials that determine their practicability and fields of applications are dielectric constant ( ɛ r ), quality factor ( Q × f ), and resonant frequency of temperature coefficient ( τ f ) 3 .…”

Structure, far-infrared spectroscopy, microwave dielectric properties, and improved low-temperature sintering characteristics of tri-rutile Mg 0.5Ti 0.5TaO 4 ceramics

“…The increasing development of fifth-generation (5G) technology stimulates enormous strict demands of electronic devices operating at the high-frequency millimeter-wave region, including high transmission speed, low insertion loss, and tunability of resonant frequency (f) [1][2][3][4]. Under these circumstances, microwave dielectric ceramics are extensively studied and regarded as promising candidates for the advantages of device size controllability and excellence in microwave dielectric properties.…”

Influences of substituting of (Ni1/3Nb2/3)4+for Ti4+on the phase compositions, microstructures, and dielectric properties of Li2Zn[Ti1−x(Ni1/3Nb2/3)x]3O8(0 ≤x≤ 0.3) microwave ceramics

“…Therefore, microwave dielectric ceramics have become a major scholarly research topic as a key component for the fabrication of these electronics [1,2]. In general, favorable performances for microwave dielectric ceramics are a moderate dielectric constant (εr), a high quality factor (Q×f), and a near-zero temperature coefficient of resonant frequency (τf), which can ensure the miniaturization of electronics, reduce the insertion loss of electronics at high frequencies, and maintain the temperature stability of electronics, respectively [3][4][5][6]. To achieve this target, enormous efforts have been made to explore a variety of novel ceramic systems such as Li2Mg3TiO6, Li2ATi3O8 (A=Mg, Zn, Co), Li4MgSn2O7, Li9Zr3NbO13, Li6Mg7Ti3O16, Li2AGeO4, Li4Mg3Ti2O9, and LiAlW2O8 [7][8][9][10][11][12][13][14].…”