Low temperature co-fired diopside glass ceramic with silver, copper diffusion effect and microwave antenna characteristics

• Main Authors: Chun-Yao Chang, 張俊堯
• Other Authors: NONE
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/94263915717244738418

碩士 === 國立臺灣科技大學 === 機械工程系 === 103 === The object of this study is to investigate the microwave dielectric materials used in the development of high-frequency components production. Diopside glass ceramics with low dielectric constant (k), high quality factor (Qxf) and low resonance frequency temperature coefficient (τf) is suitable for be used in the microwave circuit elements. Development the material system which can co-fired well with a silver and the copper electrodes,and manufactured microwave components by low temperature co-fired ceramic, were also carried out in this work . First, to establish applicability of CaMgSi2O6 in microwave components, making the cylinder CaMgSi2O6 fed into special circuitry to formed dielectric resonator antenna, designed outstanding antenna elements by using high quality factor material. Diopside sintered in atmospheric and in nitrogen, which S11 reflection coefficient are -12.008dB, -12.679 dB; efficiency 75.08%, 82.59%, respectively, showing excellent device characteristics. Furthermore, explore the co-firing effect with a silver and a copper in this system, however. Different from other LTCC material systems, Diopside ceramic glass is a highly crystalline materail, and the silver spread with glass bonding after oxidized, so the silver be pushed to the glass substrate in the bonding process, after precipitation, the silver will be distributed in electrode boundary by irregular flakes way, in the 900oC, 2hr sintering. Silver will spread to the glass ceramic body 60μm, and exist in the diffusion body about 45% by evaluated in quantitative Phase. On the other hand, in order to solve the problem of silver diffusion, this study added amorphous silicon oxide according to the literature. It can be effectively suppressed diffuse of silver when the amorphous silicon oxide is added, because the amorphous silicon oxide can increase the glass viscosity, reduced the kinetic energy of silver diffuse. In addition, before the nano amorphous silicon oxide particles reached the temperature of a large number of silver diffusion, it was gradually crystallized into quartz phase (Quartz) to block the silver which already integrated into the vitreous continue bond with the vitreous. So can be found the silver in the electrode boundary(3μm).Additionally, magnesium zinc silicon ceramics can reduce the amount of material in the vitreous, but it still can't suppressed the silver diffusion effectively. The diffusion reaction with the Copper is different from the silver metal,it will form copper compounds as Cu2MgO3, Ca2CuO3 and Ca2MgSi2O7, Mg2SiO4, SiO2 secondary phase, irregular changes of electrode boundary element formed block distribution. To suppress copper diffusion need to reduce the possibility of produced Cu2MgO3 and Ca2CuO3, when adding 4wt% silicon oxide, can be used in suppressed the diffusion of copper, using these method the boundary element distribution significantly. Finally, as IEEE 802.11a 5.8GHz as target specification to manufacture LTCC antenna by CaMgSi2O6, designed the broadband antenna using adjacent mode, and different degrees of diffusion of silver. In the result, making outstanding LTCC antenna by using CaMgSi2O6 added silicon oxide (4wt%) to suppress the diffusion of silver, the reflection loss: -27.19dB, center resonance frequency: 5.43GHz, Bandwidth: 135MHz, gain: 2.47dB, efficiency: 47.85%. Therefore, the excellent microwave dielectric electrical materials development and matching can develop a superior microwave communications component