Lanthanum-containing molybdate microwave dielectric ceramic with ultra-low dielectric constant

Abstract

The invention discloses a high quality factor temperature stable ultra-low dielectric constant microwave dielectric ceramic, which is characterized in that the chemical composition of the microwave dielectric ceramic is: BiLa3Mo2O12. The steps of the preparation method of the microwave dielectric ceramic are: (1) weighing the original powders of Bi2O3, La2O3 and MoO3 with a purity of more than 99.9% (weight percentage) according to the composition of BiLa3Mo2O12; The raw materials were mixed by wet ball milling for 12 hours, the ball milling medium was absolute ethanol, and after drying, they were pre-fired in the atmosphere at 1050°C for 6 hours; (3) After adding a binder to the powder prepared in step (2) and granulating, Then press molding, and finally sintering in the air atmosphere at 1100-1150 DEG C for 4 hours; the binder uses a polyvinyl alcohol solution with a mass concentration of 5%, and the amount of polyvinyl alcohol added accounts for 3% of the total mass of the powder. The ceramic prepared by the invention is well sintered, the dielectric constant reaches 12.8-13.7, its quality factor Qf value is as high as 97000-136000 GHz, and the temperature coefficient of resonance frequency is small, so it has 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 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 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 its resonant frequency temperature coefficient and quality factor, explore and develop near-zero resonant frequency temperature coefficient (-10ppm / ℃≤τ f ≤+10ppm / °C) and a series of different dielectric constant microwave dielectric ceramics with higher quality factors are difficult problems 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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