High-Q dielectrics using ZnO-modified Li2TiO3 ceramics for microwave applications

Huang, Cheng Liang; Tseng, Yu Wei; Chen, Jhih Yong

doi:10.1016/j.jeurceramsoc.2012.03.030

Cited by 61 publications

(18 citation statements)

References 34 publications

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“…The peaks for the x = 0.4 and 0.5 samples matched well with the standard pattern of a cubic LiTiO 2 phase (JCPDS #16-0223, Fm-3 m space group). As a result, a single rock salt-type continuous solid solution was formed, which was in good agreement with the previous work on MgO/ZnO-doped Li 2 TiO 3 ceramics [1,2]. Considering that Ni has a similar ionic radius with Mg and Zn, the replacement mechanism could also be proposed as 2Li ?…”

Section: Methodssupporting

confidence: 89%

“…Figure 3 illustrates SEM micrographs of thermallyetched (1 -x)Li 2 TiO 3 -xNiO ceramics sintered at 1250°C. All the specimens in present study showed porous microstructure similar to that of Li 2 TiO 3 -MgO/ZnO ceramics [1,2]. With increasing the NiO content, the amount of pores increased obviously and the average grain size decreased from 50 to 5 lm.…”

Section: Methodsmentioning

confidence: 51%

“…It would be specially mentioned that both a significant enhanced Q 9 f value (*100,000 GHz) and a near-zero s f value could be obtained in MgO/ZnO modified Li 2 TiO 3 ceramics. Meanwhile, an order-disorder transition appeared as the same amount of additives was added [1,2]. This phenomenon was also found in Li 2 TiO 3 with the substitution of (Zn 1/3 Nb 2/3 ) 4? for Ti 4?…”

Section: Introductionmentioning

confidence: 89%

“…Moreover, the variation of e r values presented the same trend as that of relative density with increasing sintering temperature and x, indicating relative density was one of the primary factors affecting e r in this work. In addition, e r is known to be affected by the molecular volume and ionic polarizability [2]. The observed dielectric constant of Li 2 TiO 3 -NiO samples could be corrected by porosity using the following equation [21]:…”

Section: Methodsmentioning

confidence: 99%

“…Their microstructures were characterized by obvious transgranular fracture and a lot of remaining pores, which had a detrimental effect on the inherent microwave properties. It was generally believed that the relatively high temperature (*1300°C) and large s f value would extremely restrict direct applications [1][2][3][4][5][6][7][8]12]. Sintering aids, such as B 2 O 3 -CuO, Li 2 OZnO-B 2 O 3 , LiF, etc., were used to successfully lower the sintering temperature to 900°C without obviously deteriorating the performance [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

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Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

Zhang

Zuo

2016

J Mater Sci: Mater Electron

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Rock salt-structured (1 -x)Li 2 TiO 3 -xNiO (0 B xB0.5) solid solutions were prepared via a conventional solid-state method. The structure evolution, sintering behavior, and microwave dielectric properties were investigated systematically. The phase transition from an ordered monoclinic to a disordered cubic phase was observed as x increased from 0 to 0.4. Disordered cubic phases in x = 0.4-0.5 samples seemed to conform to the structure of LiTiO 2 instead of Li 2 TiO 3 . The possible reason was ascribed to both the appearance of Ti 3? in the NiOmodified matrix and the lattice distortion from substituted ions with different radii. With a gradual decline of the structure order degree, s f was found to decrease from ?26 to -36 ppm/°C. A greatly improved Q 9 f value of 103,050 GHz (at 7.65 GHz) could be yielded at x = 0.1 owing to the increased packing fraction. The 0.8Li 2 TiO 3 -0.2NiO ceramic exhibited excellent overall microwave dielectric properties of e r = 20.4, Q 9 f = 83,608 GHz (at 7.63 GHz) and s f = 1.97 ppm/°C as sintered at 1250°C. After the addition of 1 wt% BaCuB 2 O 5 , the x = 0.2 ceramic can be well densified at 850°C and chemically compatible with pure silver, in addition to keeping superior properties of e r = 19, Q 9 f = 62,252 GHz (at 7.84 GHz) and s f = -1.65 ppm/°C. All the above results indicate that the current material system would be a promising candidate for the application of low-temperature co-fired ceramics.

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Section: Methodssupporting

confidence: 89%

Section: Methodsmentioning

confidence: 51%

Section: Introductionmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

Zhang

Zuo

2016

J Mater Sci: Mater Electron

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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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Temperature Stability of Li₂TiO₃‐Zn₂SiO₄ Microwave Dielectric Ceramics

Wang

Lai

et al. 2022

Eur J Inorg Chem

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In this work, microstructure, composition, and microwave dielectric properties of nominal compositions (1‐x)Li2TiO3‐xZn2SiO4 (x=0.1, 0.2, 0.3, 0.4), which were prepared by conventional solid‐state ceramic route, have been investigated. Li2TiO3 and Zn2SiO4 reacted to form Li2ZnSiO4 and Zn2Ti3O8, where Zn2Ti3O8 is formed during Zn2TiO4 cooling. The microwave dielectric properties of samples are mainly affected by the characteristics and relative content of crystal phase and densification. With the increase of x, the relative dielectric constant (ϵr) decreases gradually. The quality factor (Qf) value increases at first, reaches the maximum value at x=0.2, and then decreases. The temperature coefficient of resonance frequency (τf) value has a sharp decrease due to the increase of Li2ZnSiO4. A near zero τf of about −2.0 ppm/°C was obtained in 0.8Li2TiO3–0.2Zn2SiO4 ceramic sintered at 1150 °C for 4 h with ϵr value of 17.67, Qf value of 19,600 GHz. Thus, it could be a candidate for microwave devices.

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High-Q dielectrics using ZnO-modified Li2TiO3 ceramics for microwave applications

Cited by 61 publications

References 34 publications

Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

Temperature Stability of Li₂TiO₃‐Zn₂SiO₄ Microwave Dielectric Ceramics

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High-Q dielectrics using ZnO-modified Li2TiO3 ceramics for microwave applications

Cited by 61 publications

References 34 publications

Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

Low-temperature fired thermal-stable Li2TiO3–NiO microwave dielectric ceramics

List of Low‐Loss Ceramic Dielectric Materials and Their Properties

Temperature Stability of Li2TiO3‐Zn2SiO4 Microwave Dielectric Ceramics

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Temperature Stability of Li₂TiO₃‐Zn₂SiO₄ Microwave Dielectric Ceramics