A temperature-stable ultra-low dielectric constant microwave dielectric ceramic and its preparation method

Abstract

The invention discloses temperature-stable microwave dielectric ceramics LiAl3B4O11 with ultralow dielectric constant and a preparation method thereof. The preparation method comprises the steps: (1) weighing and dosing the raw material powder of Li2CO3, Al2O3 and H3BO3 with purity of more than 99.9% (weight percentage) according to the composition of the LiAl3B4O11; (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 700 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 820 degrees centigrade, wherein the mass concentration of the adhesive is polyving akohol solution of 5% and the dosage of the polyving akohol accounts for 4% that of the total mass of the poweder. The prepared ceramics are sintered well and the dielectric constant is up to 7.3-7.8; the quality factor Qf value is up to 142,000-181,000GHz; 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

LiFe 3 B 4 o 11 Ceramic resonant frequency temperature coefficient τ ? Too large (respectively +64ppm / ℃) and cannot be used as a practical microwave dielectric ceramic; while LiGa 3 B 4 o 11 with LiBi 3 B 4 o 11 As a semiconductor, its dielectric loss is too large to be used as a microwave dielectric ceramic

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