Low-loss, temperature-stabilized and ultra-low dielectric constant type microwave dielectric ceramic LiZnV5O14

Abstract

The invention discloses a temperature-stabilized and ultra-low dielectric constant type microwave dielectric ceramic LiZnV5O1 capable of being sintered at low temperature and a preparation method thereof. The method comprises the following steps: (1) weighting and mixing raw powder with purity exceeding 99.9% by weight of Li2CO3, ZnO and V2O5 according to the composition of the LiZnV5O1; (2) performing ball milling and mixing for the raw materials obtained in step (1) by a wet manner for 12 hours, wherein distilled water is used as a ball mill medium; pre-sintering for 6 hours in the atmosphere at temperature of 750 DEG C after drying; and (3) adding an adhesive to the powder obtained in the step (2), granulating, pressing and forming, and then sintering for 4 hours in the atmosphere at the temperature of 800 to 850 DEG C, wherein the adhesive is a polyving akohol solution with mass concentration of 5%; the quantity of added polyving akohol is 3% of the total mass of the powder. The ceramic prepared by the method can be sintered well at the temperature not greater than 850 DEGG C; the dielectric constant is up to 15.6 to 16.2; the quality factor (QF) is up to 119000 to 161000GHz; the resonant frequency temperature coefficients are small; the ceramic has extremely large application value in the industry.

Description

Technical field [0001] The invention relates to a dielectric ceramic material, in particular to a dielectric ceramic material used for manufacturing microwave components such as ceramic substrates, resonators and filters used in microwave frequencies, and a preparation method thereof. Background technique [0002] Microwave dielectric ceramics refer to ceramics that are used as dielectric materials and perform one or more functions in circuits in the microwave frequency band (mainly UHF and SHF frequency bands). They are widely used as resonators, filters, and dielectric bases in modern communications. Chips and dielectric guided wave circuits are the key basic materials of modern communication technology. They have been used in portable mobile phones, car phones, cordless phones, TV satellite receivers and military radars. They are used in modern communication tools. The process of miniaturization and integration is playing an increasingly important role. [0003] The dielectric ...

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Problems solved by technology

[0009] In the process of exploring and developing new low-firing microwave dielectric ceramic materials, material systems such as Li-based compounds, Bi-based compounds, tungstate compounds, and tellurate-based compounds with inherently low sintering temperatures have received extensive attention and research. However, due to the three performance indicators of microwave dielectric ceramics (ε r with Q f and τ f ) is a mutual restrictive relationship (see literature: The restrictive relationship between the dielectric properties of microwave dielectric ceramic materials, Zhu Jianhua, Liang Fei, Wang Xiaohong, Lu Wenzhong, Electronic Components and Materials, Issue 3, March 2005), satisfying three There are very few single-phase microwave dielectric ceramics that require high performance and can be sintered at low temperature, mainly because their resonant frequency temperature coefficient is usually too large or the quality factor is too low to meet the practical application requirements.

At present, most of the research on microwave dielectric ceramics is a summary of experience obtained through a large number of experiments, but there is no complete theory to explain the relationship between microstructure and dielectric properties. Predict the microwave dielectric properties such as its resonant frequency temperature coefficient and quality factor, which largely limits the development of low temperature co-firing technology and microwave multilayer devices

Exploration and development can not only sinter at low temperature but also have near-zero resonance frequency temperature coefficient (-10ppm / ℃≤τ f ≤+10ppm / °C) and high quality factor microwave dielectric ceramics are difficult problems that those skilled in the art have been eager to solve but have always been difficult to achieve

[0010] Our composition of LiZnV 5 o 14 、LiCuV 5 o 14 、LiNiV 5 o 14 A series of compounds have been studied on the microwave dielectric properties and found that their sintering temperature is lower than 900 ° C, but only LiZnV 5 o 14 With near-zero resonant frequency temperature coefficient and high quality factor, LiNiV 5 o 14 Ceramic resonant frequency temperature coefficient τ f Too large (respectively -77ppm / ℃) and the dielectric loss is also high, so it cannot be used as a practical microwave dielectric ceramic

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