Microwave dielectric properties of Ca4La2Ti5O17–LaAlO3 system ceramic materials

Chen, Guohua; Di, Jie-chang; Xu, Huarui; Yang, Yun; Yuan, Changlai; Zhou, Changrong; Cheng, Jinrong; Liu, Xinyu

doi:10.1007/s10854-011-0404-z

Cited by 5 publications

(2 citation statements)

References 9 publications

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“…However, precise calculation of the quality factor of mixed ceramic system is still illusive. Especially when the extra new phase(s) appears, it would complex the calculation of the quality factor 40 .…”

Section: Introductionmentioning

confidence: 99%

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Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

Chen

et al. 2017

Sci Rep

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Microwave dielectric ceramic materials are extensively utilized in microwave applications because of their high dielectric constants and quality factors. These applications also require ceramics of zero temperature coefficients at the resonant frequency (τ f), which can be realized through mixing a ceramic that one is interested in with another ceramic with −τ f, or by performing the ionic substitution. With the mixing/ionic substitution, it is indispensable to compute the quality factors precisely. Previous study indicates that the quality factor depends on the grain size, porosity, internal strain, structure, phase evolution, and conductivity etc. Here we derive a quality factor formula based on the definition, which works very well for multiphase composites, single phase solid solutions, and equivalent ionic substituted single phase materials. Our formula calculation and fits to the previous experimental results demonstrate that the quality factor of the ceramic mixtures strongly depend on the dielectric constants and the dielectric constant variation index. Our results suggest that the impacts from grain size, porosity, and internal strain etc. can be summarized to the dielectric constant or dielectric constant variation index, which is of great importance for future design of high performance microwave dielectric ceramics.

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Section: Introductionmentioning

confidence: 99%

“…Because the volume molar ratio of the extra new phases was not reported in previous literatures 40–43 , the examples presented in this paper do not include the case where extra phases exist. We first revise the Maxwell-Wagner equation and then derive a precise Q formula by the definition.…”

Section: Introductionmentioning

confidence: 99%

Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

Chen

et al. 2017

Sci Rep

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List of Low‐Loss Ceramic Dielectric Materials and Their Properties

2017

Microwave Materials and Applications 2V Set

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AbbreviationsST = sintering temperature ( • C) r = relative permittivity , f = measurement frequency (GHz) f = coefficient of temperature variation of resonant frequency (ppm/ • C) No. = serial number Qf = quality factor frequency product (GHz)The table lists the key property data of microwave dielectric materials available from published materials. These data are the relative permittivity ( r ), the product of the Q-factor and the frequency (Qf ), the frequency of measurement (f), and the temperature coefficient of the resonant frequency ( f ). In tabulating these data, we make no judgment on the measurement method and the reliability of the result. It is known that the ceramic properties such as porosity, grain size, raw materials used, impurities, measurement methods, and equipment used for measurements affect the dielectric properties and readers should be aware that exact comparison of data on materials of identical composition and manufactured in different laboratories using different processing conditions and measured by different methods would be expected to lead to small variations in properties. The data of dielectric measurements carried out using impedance methods at low (MHz) frequency is excluded as the errors in these methods mean that a loss tangent less than 10 −3 is unreliable. The data are arranged in the order of increasing relative permittivity. The quality factor of the microwave dielectric ceramics decrease significantly with increasing relative permittivity, as shown in Figure A.1. The inset in the figure shows the variation of quality factor frequency product with Microwave Materials and Applications, First Edition. Edited by Mailadil T. Sebastian, Rick Ubic and Heli Jantunen.

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Phase evolution and microwave dielectric properties of (Ca/Sr)Nd₄Ti₅O₁₇–based ceramic systems

Muhammad¹,

Khan²,

Hussain³

et al. 2019

Mater. Res. Express

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Microwave dielectric properties of Ca4La2Ti5O17–LaAlO3 system ceramic materials

Cited by 5 publications

References 9 publications

Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

Phase evolution and microwave dielectric properties of (Ca/Sr)Nd₄Ti₅O₁₇–based ceramic systems

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Microwave dielectric properties of Ca4La2Ti5O17–LaAlO3 system ceramic materials

Cited by 5 publications

References 9 publications

Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

Determining the Quality Factor of Dielectric Ceramic Mixtures with Dielectric Constants in the Microwave Frequency Range

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

Phase evolution and microwave dielectric properties of (Ca/Sr)Nd4Ti5O17–based ceramic systems

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Product

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Phase evolution and microwave dielectric properties of (Ca/Sr)Nd₄Ti₅O₁₇–based ceramic systems