Temperature stable ultra-low dielectric constant microwave dielectric ceramic and preparation method thereof

Abstract

The invention discloses a temperature stable ultralow dielectric constant microwave dielectric ceramic YNbW2O10 and a preparation method thereof. The preparation method comprises the following steps: (1) weighing and proportioning original powder of Y2O3, Nb2O5 and WO3 with the purity being over 99.9% (in percentage by weight) according to composition of YNbW2O10; (2) mixing the raw materials for 12h by wet ball-milling, wherein the ball-milling medium is distilled water, and drying and pre-sintering for 6 hours in an atmosphere of 850 DEG C; and (3) adding an adhesive into the powder prepared in the step (2) and granulating, then, carrying out pressure moulding, and finally, sintering in the atmosphere at of 900-930 DEG C for 4 hours, wherein the adhesive is a 5% polyvinyl alcohol solution in mass concentration, and the addition of polyvinyl alcohol accounts for 3% of total weight of powder. The ceramic prepared by the method is well sintered at 900-930 DEG C, and the dielectric constant reaches 11.6-12.3, the quality factor Qf value reaches up to 79000-88000GHz, and the temperature coefficient of resonance frequency is small. The ceramic has an extremely huge application value in industry.

Description

technical field [0001] The invention relates to a microwave dielectric ceramic material, in particular to a dielectric ceramic material used for manufacturing microwave components such as dielectric substrates, ceramic resonators and filters, and a preparation method thereof. Background technique [0002] Microwave dielectric ceramics refer to ceramics that are used as dielectric materials in circuits in the microwave frequency band (mainly UHF and SHF bands) and perform one or more functions. They are widely used as resonators, filters, and dielectric substrates in modern communications. Components such as chips and dielectric waveguide 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. It is playing an increasingly important role in the process of miniaturization and integration. [0003]...

AI Technical Summary

Problems solved by technology

[0010] 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 individual performance and can be sintered at low temperature, and their temperature coefficient of resonance frequency is usually too large or the loss is too large and the quality factor is too low to be practically produced and applied.

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 its microstructure and dielectric properties. Predict whether it has the numerical range of performance parameters such as microwave dielectric properties and resonant frequency temperature coefficient and quality factor, which largely limits the development of low temperature co-firing technology and microwave multilayer devices

Therefore, it is necessary to explore and develop materials that can be sintered at low temperature and have near-zero resonant frequency temperature coefficient (τ) f ≤10ppm / ℃) and high quality factor (Q·f≥50000GHz) microwave dielectric ceramics is a difficult problem that those skilled in the art have been eager to solve but have always been difficult to achieve

Our pairs become La 2 Bi 5 V 3 o 18 、Nd 2 Bi 5 V 3 o 18 、Sm 2 Bi 5 V 3 o 18 、Pr 2 Bi 5 V 3 o 18 The microwave dielectric properties of the vanadates were studied, in which it was found that their sintering temperature was lower than 900 °C, but only La 2 Bi 5 V 3 o 18 It has near-zero resonant frequency temperature coefficient and high quality factor, and the resonant frequency temperature coefficient of other ceramics is too large (>30ppm / ℃)

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