Eight-layer hexagonal perovskite microwave dielectric ceramic with resonance frequency temperature coefficient approximate to zero and preparation method of eight-layer hexagonal perovskite microwave dielectric ceramic

Abstract

The invention discloses an eight-layer hexagonal perovskite microwave dielectric ceramic with adjustable parameters that the dielectric constant epsilon is within 29-35, the product of a quality factor and a resonant frequency (Q*f) is 20000-70000GHz, and the resonance frequency temperature coefficient ([tau]f) is within 0-63ppm / DEG C, and a preparation method of the eight-layer hexagonal perovskite microwave dielectric ceramic, and belongs to the technical field of microwave dielectric ceramic preparation. The chemical constitution of the ceramic is Ba8CoNb6-xTaxO24 (x=1-6), when x is greaterthan or equal to 0 and less than or equal to 2, the ceramic is of a displacement structure, and when x is greater than or equal to 3 and less than or equal to 6, the ceramic is of a twinborn structure. According to the ceramic, structure configuration conversion is resulted from equivalent ion substitution, the resonance frequency temperature coefficient of the eight-layer hexagonal perovskite microwave dielectric ceramic is adjustable, and the ceramic is simple in constitution and preparation process and can be applied to fields such as single-phase dielectric resonators with adjustable resonance frequency temperature coefficients, and microwave integrated circuit substrates.

Description

technical field [0001] The invention relates to a dielectric ceramic material for microwave devices such as dielectric resonators, microwave integrated circuit substrates and filters used at microwave frequencies and a preparation method thereof. Background technique [0002] Microwave dielectric ceramics are a new type of electronic multifunctional ceramic materials that have developed rapidly in recent decades. Due to their high dielectric constant, high quality factor and low resonance frequency temperature coefficient, they are used as microwave electronic components such as dielectric resonators / filters It is widely used in microwave communication systems such as mobile communication, satellite communication, global satellite positioning system, bluetooth equipment and wireless local area network. Microwave dielectric ceramic materials currently used in communication equipment need to meet the quality factor Q×f~30000GHz, the dielectric constant ε between 20-100 and the...

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Problems solved by technology

Hexagonal perovskite and cubic perovskite have the same structural unit and rich chemical composition. According to the difference in octahedral arrangement, it can be divided into displacement type and twin structure. Among them, the 8-layer hexagonal perovskite exhibits excellent microwave dielectric properties. Performance, quality factor Q×f~30000-100000GHz, dielectric constant ε~30-40, but resonant frequency temperature coefficient τ f >0(25-40ppm / ℃), which limits the application of 8-layer hexagonal perovskite in the field of microwave dielectric materials

At present, single-phase 8-layer hexagonal perovskite materials that meet the application requirements of dielectric resonator / filter electronic components are scarce due to the resonant frequency temperature coefficient of nearly 0ppm / °C obtained by equivalent ion substitution.

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