Lattice dynamics and terahertz response of microwave dielectrics: A case study of Al-doped Ca0.6Sm0.27TiO3 ceramics

Guo, Weijia; Ma, Zhiyu; Chen, Yugu; Lu, Yutian; Yue, Zhenxing

doi:10.1016/j.jeurceramsoc.2022.05.045

Cited by 30 publications

(11 citation statements)

References 68 publications

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“…As the frequency increases, the α and ε'' of CaLa 2 (MoO 4 ) 4 continuously increase, while the n and ε' remain relatively constant. This response is consistent with other MWDC systems in the THz range. 34 The ε r of CaLa 2 (MoO 4 ) 4 ceramic in the microwave frequency range (10.11) is very close to that measured in the THz range (9.5 to 9.9).…”

Section: Resultssupporting

confidence: 90%

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Bao,

Du,

et al. 2023

J Am Ceram Soc.

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In this study, two novel microwave dielectric ceramics were designed and synthesized using the solid‐state reaction method based on the CaO–MoO3–La2O3 pseudo‐ternary phase diagram. The X‐ray diffraction (XRD) patterns and Rietveld refinement results indicate that pure phase microwave dielectric ceramics (CaLa2(MoO4)4 and Ca3MoO6) can be produced with CaO, MoO3, La2O3 ratios of 1, 1, 4, and 3, 1, 0, respectively. CaLa2(MoO4)4 shows the potential value for application in Low Temperature Co‐fired Ceramic technology. In addition, the Phillips–van Vechten–Levine theory, infrared reflectance spectrum, and THz time‐domain spectrum are used further to study the structure‐property relationship of the two ceramics. Finally, a 5G patch antenna used in Sub‐6 GHz communication technology was successfully designed and manufactured. The study of the relationship between chemical bonds and dielectric properties of the two ceramics, along with the development of the patch antenna, establishes a foundation for scientific research and practical applications in related ceramic systems.

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Section: Resultssupporting

confidence: 90%

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Bao,

Du,

et al. 2023

J Am Ceram Soc.

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“…With increasing BaF 2 proportion, no significant displacement of all Raman-active modes of BaSO 4 was observed, but a slight decrease in the half-height width of A g ( v 1 ) occurred. According to the classical radiation theory, the reduced half-height width represents the weakening of the damping factor γ or nonresonance effects, which is consistent with the improvement in Q × f values. At the same time, another Raman-active mode B 2g gradually appears at 240–245 cm –1 in composite compositions, related to the mutual vibration of adjacent F – along the grain axis direction, which may contribute to more electronic polarization.…”

Section: Resultssupporting

confidence: 73%

“…This indicates the contributions of some lowfrequency phonon modes or phonon scattering from structural defects. 25,29,30 The primary problem in the joint use of LTCC, organic laminates, and solders is due to their mismatch in CTE. This mismatch leads to significant thermal stress on packaged components when subjected to temperature loads, which can compromise the reliability of the packaged system.…”

Section: Resultsmentioning

confidence: 99%

Low-Permittivity and Low-Temperature Cofired BaSO₄–BaF₂Microwave Dielectric Ceramics for High-Reliability Packaged Electronics

Wang,

Shehbaz,

Wang

et al. 2023

ACS Appl. Mater. Interfaces

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In developing low-temperature cofired ceramic (LTCC) technology for high-density packaging or advanced packaged electronics, matching the coefficient of thermal expansion (CTE) among the packaged components is a critical challenge to improve reliability. The CTEs of solders and organic laminates are usually larger than 16.0 ppm of °C1–, while most low-permittivity (εr) dielectric ceramics have CTEs of less than 10.0 ppm °C1–. Therefore, a good CTE match between organic laminates and dielectric ceramics is required for further LTCC applications. In this paper, we propose a high-CTE BaSO4–BaF2 LTCC as a potential solution for high-reliability packaged electronics. The BaSO4–BaF2 ceramics have the advantages of a wide low-temperature sintering range (650–850 °C), low loss, temperature stability, and Ag compatibility, ensuring excellent performance in LTCC technology. The 95 wt %BaSO4–5 wt %BaF2 ceramic has a εr of 9.1, a Q × f of 40,100 GHz @11.03 GHz (Q = 1/tan δ), a temperature coefficient of the resonant frequency of −11.2 ppm °C1–, a CTE of +21.8 ppm °C1–, and a thermal conductivity of 1.3 W mK–1 when sintered at 750 °C. Furthermore, a dielectric resonant antenna using BaSO4–BaF2 ceramics, a typically packaged component of LTCC and laminate, was designed and used to verify the excellent performance by a gain of 6.0 dBi at a central frequency of 8.97 GHz and a high radiation efficiency of 90% over a bandwidth of 760 MHz. Good match and low thermal stress were found in the packaged components of BaSO4–BaF2 ceramics, organic laminates, and Sn-based solders by finite element analysis, proving the potential of this LTCC for high-reliability packaged electronics.

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“…The rapid extension of millimeter‐wave communication and terahertz (6G) technology have increased the requirements for developing high‐performance microwave dielectric ceramics with low permittivity ( ε r < 15), ultrahigh‐quality factor ( Q × f ), and near‐zero temperature coefficient of resonant frequency ( τ f ) 1–7 . High‐performance microwave dielectric ceramics are suitable for manufacturing high‐end microwave devices (dielectric resonators, filters, capacitors, and duplexers) and substrates in the field of millimeter‐wave and terahertz high‐speed communication 8–11 . Low ε r and high Q × f is needed to minimize cross‐coupling and improve signal propagation velocity, and they represent the key properties of high‐performance microwave dielectric ceramics.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7] High-performance microwave dielectric ceramics are suitable for manufacturing high-end microwave devices (dielectric resonators, filters, capacitors, and duplexers) and substrates in the field of millimeter-wave and terahertz high-speed communication. [8][9][10][11] Low ε r and high Q × f is needed to minimize cross-coupling and improve signal propagation velocity, and they represent the key properties of high-performance microwave dielectric ceramics. Furthermore, low-ε r and high-Q × f microwave dielectric ceramics are important considerations in addressing the explosive growth of high-frequency components.…”

Section: Introductionmentioning

confidence: 99%

Optimized phase compositions and microwave dielectric properties of low loss Ca₂Sn₂Al₂O₉‐based ceramics by M⁴⁺ substitution

Wen

Zhou

et al. 2023

J Am Ceram Soc.

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The traditional solid‐state reaction method was used to prepare Ca2Sn2−xMxAl2O9 (M = Ti, Zr, and Hf) ceramics. Then, the impact of an M4+ substitution of Sn4+ on the phase transition, crystal structural parameter, and microwave dielectric properties of Ca2Sn2−xMxAl2O9 (0 ≤ x ≤ 0.4) ceramics were investigated. Ti4+ could not replace the Sn4+ of Ca2Sn2Al2O9 due to its small ionic radius, and the Al‐based second phases of Ca2Sn2−xTixAl2O9 ceramics were confirmed by the X‐ray diffractometer and EDS map scanning results. With the Zr4+ and Hf4+ substitutions of Sn4+, the SnO2 and CaSnO3 second phases of Ca2Sn2Al2O9 ceramic were inhibited, and the Ca2Sn2−xMxAl2O9 (M = Zr and Hf) (0.05 ≤ x ≤ 0.2) single‐phase ceramics with orthorhombic structure (Pbcn space group) were obtained. New MO2 (M = Zr and Hf) and CaAl2O4 second phases appeared in the Ca2Sn2−xMxAl2O9 (M = Zr and Hf) (0.3 ≤ x ≤ 0.4) ceramics, and their contents increased gradually with the increase in x. The Ca2Sn2−xMxAl2O9 (M = Zr and Hf) (0.05 ≤ x ≤ 0.2) ceramics exhibited high Q × f because of their pure phase compositions, and the Q × f of Ca2Sn2Al2O9 ceramic was improved to 77 800 GHz (12.6 GHz) in the Ca2Sn1.9Zr0.1Al2O9 ceramic. The Q × f values of Ca2Sn2−xMxAl2O9 single‐phase ceramics were mainly controlled by rc (Sn/M–O) and rc (Al–O). The τf values of single‐phase Ca2Sn2−xMxAl2O9 ceramics were related to octahedral distortions. The Zr4+ and Hf4+ substitution of Sn4+ optimized the phase compositions and microwave dielectric properties of the Ca2Sn2−xMxAl2O9 ceramics, and the Ca2Sn1.9Zr0.1Al2O9 ceramic sintered at optimal temperature exhibited excellent microwave dielectric properties (εr = 8.67, Q × f = 77 800 GHz at 12.6 GHz and τf = −69.8 ppm/°C).

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Lattice dynamics and terahertz response of microwave dielectrics: A case study of Al-doped Ca0.6Sm0.27TiO3 ceramics

Cited by 30 publications

References 68 publications

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Low-Permittivity and Low-Temperature Cofired BaSO₄–BaF₂Microwave Dielectric Ceramics for High-Reliability Packaged Electronics

Optimized phase compositions and microwave dielectric properties of low loss Ca₂Sn₂Al₂O₉‐based ceramics by M⁴⁺ substitution

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Lattice dynamics and terahertz response of microwave dielectrics: A case study of Al-doped Ca0.6Sm0.27TiO3 ceramics

Cited by 30 publications

References 68 publications

Novel microwave dielectric ceramics based on CaO–MoO3–La2O3 pseudo‐ternary phase diagram and the design of patch antenna

Novel microwave dielectric ceramics based on CaO–MoO3–La2O3 pseudo‐ternary phase diagram and the design of patch antenna

Low-Permittivity and Low-Temperature Cofired BaSO4–BaF2Microwave Dielectric Ceramics for High-Reliability Packaged Electronics

Optimized phase compositions and microwave dielectric properties of low loss Ca2Sn2Al2O9‐based ceramics by M4+ substitution

Contact Info

Product

Resources

About

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Novel microwave dielectric ceramics based on CaO–MoO₃–La₂O₃ pseudo‐ternary phase diagram and the design of patch antenna

Low-Permittivity and Low-Temperature Cofired BaSO₄–BaF₂Microwave Dielectric Ceramics for High-Reliability Packaged Electronics

Optimized phase compositions and microwave dielectric properties of low loss Ca₂Sn₂Al₂O₉‐based ceramics by M⁴⁺ substitution