Temperature-stable microwave dielectric ceramics with ultralow loss and preparation method thereof

Abstract

The invention discloses temperature-stable microwave dielectric ceramics LiV2BO7 with ultralow loss and a preparation method thereof. The preparation method comprises the steps: (1) weighing and dosing the raw material powder of Li2CO3, V2O5 and H3BO3 with purity of more than 99.9% (weight percentage) according to the composition of the LiV2BO7; (2) ball-milling and mixing the raw materials in the step (1) for 12 hours in a wet method, utilizing absolute ethyl alcohol as the ball-milling medium, drying and then pre-burning for 6 hours in the air atmosphere of 650 degrees centigrade; (3) adding an adhesive to the powder prepared in the step (2), granulating, pressing and molding, and finally burning for 4 hours in the air atmosphere of 700-750 degrees centigrade, wherein the mass concentration of the adhesive is polyving akohol solution of 5% and the dosage of the polyving akohol accounts for 3% that of the total mass of the poweder. The prepared ceramics are sintered well and the dielectric constant is up to 7.2-8.2; the quality factor Qf value is up to 176,000-238,000GHz; the temperature coefficient of resonance frequency is small and the ceramics have great application value in industry.

Description

technical field [0001] The invention relates to a dielectric ceramic material, in particular to a dielectric ceramic material 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 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. [00...

AI Technical Summary

Problems solved by technology

[0008] Due to the three performance indicators of microwave dielectric ceramics (ε r with Q f and τ ? ) is a mutually 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 with individual performance requirements, 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 resonant frequency temperature coefficient and quality factor, explore and develop near-zero resonant frequency temperature coefficient (-10 ppm / ℃≤τ ? ≤+10 ppm / ℃) and a series of different dielectric constants with high quality factors 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, which largely limits the use of microwave dielectric ceramics and device development

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