Ceramic material for microwave dielectric and preparation method thereof

Abstract

A kind of ceramic material for microwave medium and preparation method thereof, the present invention will composite oxide Li 1.6 Zn 1.6 sn 2.8 o 8 As a material for microwave dielectric ceramics, this ceramic has excellent dielectric properties, with a relative permittivity of 9.83-11.24, a Q×f of 45400-59800 GHz, and a resonant frequency temperature coefficient of -6.87-9.17ppm / °C. This kind of ceramics is a low-medium microwave ceramic, and its τ f value is near zero and Q×f is high, no further adjustment of τ is required f The value can meet the requirements of microwave circuit for its temperature stability. The ceramic is prepared by a solid-state reaction method, the process is simple, and the sintering temperature is lower than 1150° C., which is easy to further reduce the sintering temperature to be used in LTCC technology. The microwave dielectric ceramic material of the present invention has rich sources of raw materials, low cost, and is conducive to industrial production. It can be used as manufacturing materials for electronic circuit substrates, dielectric resonators, filters, high-frequency satellite microwave device substrates, and microstrip lines. , microwave mobile communications, satellite communications, and radar systems have important application prospects and economic value.

Description

technical field [0001] The invention specifically relates to a ceramic material for microwave media and a preparation method thereof. Background technique [0002] Microwave dielectric ceramics refer to ceramic materials that are used as dielectric materials in microwave frequency circuits and perform one or more functions. According to the size of the dielectric constant, microwave dielectric ceramics are divided into low dielectric microwave dielectric ceramics, intermediate microwave dielectric ceramics and high dielectric microwave dielectric ceramics. In recent years, with the rapid development of modern communication technologies such as mobile communication, satellite communication, global satellite positioning system (GPS), Bluetooth technology, and wireless local area network (WLAN), microwave technology is also moving towards higher frequencies, that is, towards millimeter waves and submillimeters. direction of the wave. In addition to requiring ceramics to have ...

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Problems solved by technology

This method mainly includes two implementation methods. One is to first synthesize the precursor base material and then dope. This implementation method requires the first ball milling, and then ball milling after adding dopants. The synthesis process has many steps and is industrialized on a large scale. Production will bring about a substantial increase in cost, and at the same time, the dielectric properties of ceramics may be affected by the increase in process steps; second, doping is done during the preparation of raw materials, and the required composite crystal phase can be obtained in one synthesis process. Although the method can achieve one-time compounding, compared with the first method, the steps are simple and convenient, and the cost is low. The obtained microwave dielectric ceramics have stable performance and are suitable for large-scale production. However, the disadvantage is that not all ceramic materials of any system can be prepared by one-time synthesis. A multi-phase microwave dielectric ceramic with stable coexistence of two phases has been developed, so it lacks universality

In addition, the second phase generated by the incorporation of substances with opposite resonance frequency temperature coefficients will inevitably bring the following problems to ceramic materials: system compactness problems; sintering defects caused by sintering characteristics and thermal expansion coefficients between different phases And the doping phase and the base phase may react, so the difficulty of selecting doping materials is greatly increased

Whether ion substitution or materials with opposite resonant frequency temperature coefficients are used for compounding, complex synthesis processes will be involved, which will increase the dielectric loss of the ceramic system; and the relationship between the change of the resonant frequency temperature coefficient of the ceramic system and the change of the system composition is nonlinear. , so that the resonant frequency temperature coefficient of the ceramic is quite sensitive to the composition, and a small change in the composition will lead to a large change in performance, so the process repeatability is poor

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