MICROWAVE DIELECTRIC MATERIALS IN THE BaO–TiO2 SYSTEM

In addition to the constant demand of low-loss dielectric materials for wireless telecommunication, the recent progress in the Internet of Things (IoT), the Tactile Internet (fifth generation wireless systems), the Industrial Internet, satellite broadcasting and intelligent transport systems (ITS) has put more pressure on their development with modern component fabrication techniques. Oxide ceramics are critical for these applications, and a full understanding of their crystal chemistry is fundamental for future development. Properties of microwave ceramics depend on several parameters including their composition, the purity of starting materials, processing conditions and their ultimate densification/porosity. In this review the data for all reported low-loss microwave dielectric ceramic materials are collected and tabulated. The table of these materials gives the relative permittivity, quality factor, temperature variation of the resonant frequency, crystal structure, sintering temperature, measurement frequency and references. In addition, the methods commonly employed for measuring the microwave dielectric properties, important from the applications point of view, factors affecting the dielectric loss, methods to tailor the dielectric properties and materials for future applications, are briefly described. The data will be very useful for scientists, industrialists, engineers and students working on current and emerging applications of wireless communications.

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“…In ceramic production, τ f and ε r specifications must be produced to within demanding tolerances typically ± 1%. 2…”

Section: Introductionmentioning

confidence: 99%

Low-loss dielectric ceramic materials and their properties

Sebastian

Ubic

Jantunen

2015

International Materials Reviews

613

242

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“…One can tailor the properties of complex perovskites by suitable substitutions at A or B sites 1,4,6–8 . Among the 1:2 type ordered ceramics, Ba(Zn 1/3 Ta 2/3 )O 3 and Ba(Mg 1/3 Ta 2/3 )O 3 were found to have a high‐quality factor and a low‐temperature coefficient of resonant frequency 9–11 . Considerable work has been carried out on A(B′ 1/3 B″ 2/3 )O 3 ‐type complex perovskites, whereas relatively less attention has been paid to A(B′ 1/2 B″ 1/2 )O 3 ‐type perovskites 4–7 .…”

Section: Introductionmentioning

confidence: 99%

Microwave Dielectric Properties of Sr(B′_1/2Nb_1/2)O₃ [B′=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] Ceramics

Khalam

Sebastian

2006

Int J Applied Ceramic Tech

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Sr(B′1/2Nb1/2)O3 [B′=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] ceramics were prepared by the conventional solid‐state ceramic route. The crystal structure and microstructure of the ceramics were characterized by X‐ray diffraction and scanning electron microscopic methods, and the dielectric properties were measured in the microwave range. Addition of a small amount of CeO2 as a sintering aid improved the densification and dielectric properties of the ceramics. The effects of cation substitution and glass addition on the microwave dielectric properties of the ceramics were also investigated. Glass addition resulted in the lowering of the processing temperature of the materials without much affecting the dielectric properties, whereas cation substitution resulted in the variation of the temperature coefficient of resonant frequencies. A correlation of dielectric properties with the tolerance factor and ionic radii of B′‐site elements of the ceramics has been observed.

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“…It has been reported that extrinsic losses, especially oxygen vacancies, play a dominant role in microwave dielectric losses. 2,37 In this work, all 95MCT ceramics with various grain sizes are well densified (>97%) with a limited difference in porosity.…”

Section: Resultsmentioning

confidence: 64%

“…With the rapid development of microwave communication technologies, microwave dielectric materials for resonator filters, oscillators, antennas, and capacitors have attracted considerable attention [1][2][3] in the past decades. For microwave dielectric materials, it is preferable to have an appropriate relative permittivity ( r ), a low dielectric loss (usually characterized by Q × f, where Q = 1/tanδ) for high-frequency selectivity, and a near-zero temperature coefficient of resonant frequency ( f ) for high-temperature stability.…”

Section: Introductionmentioning

confidence: 99%

Grain size engineered 0.95MgTiO₃–0.05CaTiO₃ ceramics with excellent microwave dielectric properties and prominent mechanical performance

Wang

Guo

et al. 2021

J Am Ceram Soc

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Microwave communication systems are being developed with the goal to achieve miniaturization and high reliability. There are urgent requirements for microwave dielectric materials to exhibit low sintering temperatures, excellent microwave dielectric properties, and prominent mechanical performance. However, simultaneously achieving these requirements is a significant challenge. These concerns have been addressed in the uniform ultrafine-grained 0.95MgTiO 3 -0.05CaTiO 3 ceramics with an average grain size of ~0.6 µm via a grain size engineering strategy. Interestingly, the sintering temperature in the unique two-step sintering method of 1250℃/1 min and 1130℃/10 h is much lower (200-300℃) than that obtained in the conventional sintering method reported previously (1400-1450℃). Excellent dielectric properties are achieved, with relative permittivity ε r = 20.11, quality factor Q × f = 68 613 GHz, and temperature coefficient of resonant frequency τ f = 1.81 ppm/℃. The bending strength f , Vickers hardness H v , and elastic modulus E reach up to 212.4 MPa, 10.1 GPa, and 200.7 GPa, respectively. These values are significantly enhanced over those of samples obtained via the conventional sintering method with an average grain size of ~2.5 µm. For the first time, uniform ultrafine-grained microwave dielectric materials with excellent microwave dielectric properties and prominent mechanical performance were synthesized. This work provides a guideline for developing other high-performance microwave dielectric materials and makes a significant contribution to the miniaturization and high reliability of microwave dielectric devices.

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MICROWAVE DIELECTRIC MATERIALS IN THE BaO–TiO2 SYSTEM

Cited by 17 publications

References 113 publications

Low-loss dielectric ceramic materials and their properties

Low-loss dielectric ceramic materials and their properties

Microwave Dielectric Properties of Sr(B′_1/2Nb_1/2)O₃ [B′=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] Ceramics

Grain size engineered 0.95MgTiO₃–0.05CaTiO₃ ceramics with excellent microwave dielectric properties and prominent mechanical performance

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MICROWAVE DIELECTRIC MATERIALS IN THE BaO–TiO2 SYSTEM

Cited by 17 publications

References 113 publications

Low-loss dielectric ceramic materials and their properties

Low-loss dielectric ceramic materials and their properties

Microwave Dielectric Properties of Sr(B′1/2Nb1/2)O3 [B′=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] Ceramics

Grain size engineered 0.95MgTiO3–0.05CaTiO3 ceramics with excellent microwave dielectric properties and prominent mechanical performance

Contact Info

Product

Resources

About

Microwave Dielectric Properties of Sr(B′_1/2Nb_1/2)O₃ [B′=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] Ceramics

Grain size engineered 0.95MgTiO₃–0.05CaTiO₃ ceramics with excellent microwave dielectric properties and prominent mechanical performance