Development and application of ferrite materials for low temperature co-fired ceramic technology

Development and application of ferrite materials for low temperature co-fired ceramic （LTCC） technology are dis- cussed, specifically addressing several typical ferrite materials such as M-type barium ferrite, NiCuZn ferrite, YIG ferrite, and lithium ferrite. In order to permit co-firing with a silver internal electrode in LTCC process, the sintering temperature of ferrite materials should be less than 950 ℃. These ferrite materials are research focuses and are applied in many ways in electronics.

Analysis on Micro Complex Shape Via Hole Punching on Low Temperature Co-Fired Ceramics

The quality of a via hole on a multilayer stack of Low Temperature Co-fired Ceramic (LTCC) tape is of utmost importance to its functionality. This paper investigates a substitute for the commonly used circular shape hole to a more complex one and its implications when different parameters such as sheet thickness, punch speed, travel distance and tool clearance are?changed. Fabrication of the punch tools and the punching process is carried out at the same machine, ensuring alignment. Two types of non-circular shape are chosen to carry out the experiment. Pre-sintered complex shape hole measurements show that while punch conditions such as speed and tool gap have?little effect on the size, sheet thickness and travel depth play a vital role in the overall dimension. Albeit having only a slight effect on the size, those parameters are significant in other aspects of hole quality. Post-sintering investigation is also observed and discussed.

34 GHz Bandpass Filter for Low-temperature Co-fired Ceramic System-in-Package Application

Modern electronic circuit requires compact,multifunctional technology in communication systems.However,it is very difficult due to the limitations in passive component miniaturization and the complication of fabrication process.The bandpass filter is one of the most important passive components in millimeter（mm）-wave communication system,attracting significant interest in three-dimension（3D） miniaturized design,which is few reported.In this paper,a bandpass filter structure using low-temperature co-fired ceramic（LTCC） technology,which is fully integrated in a system-in package（SIP） communication module,is presented for miniaturized and high reliable mm-wave application.The bandpass filter with 3D end-coupled microstrip resonators is implemented in order to achieve a high performance bandwidth characteristic.Specifically,all of the resonators are embedded into different ceramic layers to decrease the insertion loss and enhance the out-of-band rejection performance by optimizing the coupling coefficient and the coupling strength.A fence structure,which is formed by metal-filled via array with the gap less than quarter wavelength,is placed around the embedded bandpass filter to avoid electromagnetic（EM） interference problem in multilayer structure.This structural model is validated through actual LTCC process.The bandpass filter is successfully manufactured by modifying the co-fireablity characteristics,adjusting the sintering profile,releasing the interfacial stress,and reducing the shrinkage mismatch with different materials.Measured results show good performance and agree well with the high frequency EM full wave simulation.The influence of layer thickness and dielectric constant on the frequency response in fabricated process is analyzed,where thicker ceramic sheets let the filter response shift to higher frequency.Moreover,measured S-parameters denote the center frequency is also strongly influenced by the variation of ceramic material＇s dielectric constants.By analyzing the relationship between the characteristics of the ceramic tape and the center frequency of the filter,both theoretical and experimental data are accumulated for broadening application filed.With the coupling resonators embedded into the ceramic layers,the bandpass filter exhibits advantages of small size and high reliability compared to conventional planar filter structure,which makes the bandpass filter suitable for SIP communicational application.

一种L波段新型LTCC滤波器的实现

基于滤波器技术指标,综合分析低温共烧多层陶瓷(LTCC)滤波器中集总、分布两种设计方案的优劣势,提出了一种集总元件和分布元件结合的电路,即两端电路采用集总元件,中间电路采用分布元件,并在建模中优化了元件特性。经过三维电磁软件仿真与工艺加工制作,发现该集总元件和分布元件结合的设计实现了L波段11%相对带宽下插入损耗3 dB以内,回波损耗20 dB以上,近端抑制60 dB以上,远端至X波段无明显寄生通带。测试结果、电路仿真结果和电磁场仿真结果一致性良好。

基于对称型双谐振电路的LTCC温湿传感器

为了实现高温、恶劣环境下温度和湿度复合参数测量,设计了一种基于对称型双谐振电路的双参数传感器。该传感器采用了一种独特的对称型双谐振电路,可解决多参数间物理性串扰的难题。首先通过高频结构模拟器(HFSS)对传感器电场进行仿真,采用低温共烧陶瓷(LTCC)技术对传感器进行制备,最后搭建温度和湿度平台测试并验证了传感器的可行性。测试结果表明,两个被测参数的谐振频率彼此完全独立、解耦,其中传感器的最高测试温度为500℃,随着温度的升高,温度灵敏度逐渐升高,在25~300℃、300~400℃和400~500℃范围内,温度灵敏度分别约为0.0116、0.0259和0.0493 MHz/℃,湿度灵敏度约为0.043 MHz/%RH,传感器对温度和湿度测量均表现出了良好的敏感特性。

Effects of V₂O₅Addition on Microwave Dielectric Properties of Li₂ZnTi₃O₈Ceramics for LTCC Applications

The sintering temperature of Li2ZnTi3O8 ceramics is still high for LTCC-based applications. In this work, V2O5 was doped as the sintering aid. The sintered density, phase composition, grain size, as well as microwave dielectric properties of Li2ZnTi3O8 ceramics with the addition of V2O5 were investigated. Based on our research, V2O5 doping effectively promoted the densification of Li2ZnTi3O8 ceramics at about 900°C, without affecting the main crystal phase of the ceramics. Li2ZnTi3O8 ceramics with 0.5 wt% V2O5 doping (sintered at 900°C) exhibited the best microwave dielectric properties (Qf =?22,400 GHz at about 6 GHz, εr = 25.5, and τf = -10.8 ppm/°C). The V2O5-doped Li2ZnTi3O8 ceramics were well cofired with Ag inner paste without cracks and diffusion, indicating its significant potential for LTCC applications.

Multilayer Low Pass Filter Using LTCC Technology

The implementation and characteristics of a compact lumped-element three-order low pass filter are presented in this paper. The filter with 120 MHz cut off frequency, as well as more than 20 dB of the attenuation above 360 MHz frequency band is successfully manufactured in an LTCC substrate with 40 pm layer thickness. The overall size of the filter is 2.0 mm×1.2 mm×0.9 mm. A good coincidence between the measured results and the full-wave electromagnetic designed responses is observed.

基于LTCC的X波段四通道发射SiP模块

面向雷达相控阵系统应用,研制了一款X波段四通道发射封装内系统(SiP)模块。SiP模块采用低温共烧陶瓷(LTCC)基板,共28层,设计最小线宽为150μm,且内置埋阻。模块集成了驱动放大器、低噪声放大器(LNA)、幅相多功能等芯片,并将四功分器和交叉带状线网络设计于基板内部,提高了模块的集成度和通道间隔离度,采用内部互连的LTCC基板实现了多种有源器件和无源结构的三维集成。测试结果表明,在工作频率9~10.5 GHz,SiP模块单通道增益≥37 dB,输出功率可达24 dBm,通道间隔离度≥25 dB。SiP模块尺寸仅为20 mm×20 mm×2.65 mm,质量约3.35 g。实现了X波段多通道SiP模块的高性能、高集成度和小型化,可广泛应用于相控阵雷达的T/R组件中。

大尺寸LTCC焊接组件热变形特性的仿真研究

为了研究不同封装条件对低温共烧陶瓷(LTCC)基板封装焊接后残余热应力的影响,该文针对不同温变载荷下LTCC基板的热应力变形进行了仿真计算和实验测试,结果显示仿真计算与实验测试结果具有较好的一致性,验证了数值仿真用于LTCC基板封装焊接后残余热应力仿真的可行性。在此基础上对零膨胀合金底板和硅铝合金封装条件下3种典型工作温度对应的LTCC基板的热应力进行了仿真计算。结果表明,封装焊接后LTCC基板两侧边缘应力集中,中间残余应力小,呈翘曲状态,采用硅铝合金封装焊接的热应力小于零膨胀合金封装。

新型LTCC高隔离低插损3 dB 90°电桥设计

基于宽边耦合带状线结构,该文设计了一种基于低温共烧陶瓷(LTCC)技术的高隔离低插损3 dB 90°电桥。该电桥使用螺旋耦合线有效地减小了器件尺寸,同时以对称式结构建模更便于后期的优化调整。在宽边螺旋耦合带状线垂直方向引入一个伸入式可调隔离电容,极大地提高了该电桥的隔离度,使其可达27 dB,且插入损耗≤0.2 dB,较之传统的定向耦合器结构,其在提升性能的同时大幅减小了器件尺寸。对耦合线直角拐弯处的电场强度进行分析与优化,采用45°斜切的方式使拐角处的电场强度与直线处大致相等。对上接地金属板进行环形镂空处理,这将改善带内的幅度平衡度。该文设计的3 dB 90°电桥通带为0.96~1.53 GHz,插入损耗≤0.2 dB,幅度平衡度≤±0.7 dB,相位平衡度为90°±1°,隔离度≥27 dB,其具有良好的应用市场。

1.5~1.7 GHz小型化LTCC电桥的设计

采用低温共烧陶瓷(Low Temperature Co-fired Ceramic,LTCC)工艺技术,仿真设计了一款1.5~1.7 GHz的3 dB小型化LTCC电桥,芯片尺寸仅为2.04 mm×1.29 mm×1.16 mm。该电桥采用2条耦合阿基米德螺旋线的方式来实现,使得耦合层的结构及各项指标能够灵活调试,增加了频率调整的灵活性,同时采用双层平行耦合结构,未占用电桥XY平面的尺寸,实现了小型化。在工艺上,该结构采用半孔接触及接地代替了侧印,降低了工艺复杂性,利于批产的实现。该3 dB电桥电性能优异,插入损耗为0.6 dB,幅度不平衡度为±0.4 dB,相位不平衡度为±1°,回波损耗为-20 dB,隔离度为20 dB。

低温共烧陶瓷激光测厚系统设计与误差分析

基于提升低温共烧陶瓷(low temperature co-fired ceramic,LTCC)厚度的检测精度、测量效率和可溯源性的需求,设计一套LTCC激光测厚系统。针对测量精度难以满足需求的问题,对存在误差进行分析,采用厚度测量用调整夹具消除同轴度误差和线性度误差,优化设计结构降低倾角误差,循环传感器标定消除重复度误差,通过数据优化和滤波处理降低机械振动误差,提高了系统测量精度。与实际产品厚度数据对比,最终精度误差≤5μm,符合产品的应用要求,具有广阔的应用市场。

Crystal structure and microwave dielectric properties of novel BiMg_(2)MO_(6)(M=P,V)ceramics with low sintering temperature

Novel low-firing BiMg_(2)PO_(6)(BMP)and BiMg_(2)VO_(6)(BMV)ceramics with excellent microwave properties were synthesized and analyzed.The Rietveld refinement indicated that BiMg_(2)MO_(6)(M=p,V)ceramics crystallized in orthorhombic structure.The analysis results of the scanning electron microscope proved a dense and uniform microstructure.Further research showed that there was a strong correlation among permittivity,quality factor,and bulk density at different temperatures.The correlation between the properties and the structure of BiMg_(2)MO_(6)(M=P,V)ceramics were characterized by the chemical bond theory.The outstanding dielectric properties of BiMg_(2)MO_(6)(M=P,V)ceramics(BMP:εr=12.503,Q×f=25,760 GHz,tf=-20×10^(-6)/℃;BMV:εr=13.472,Q×f=37,270 GHz,tf=78×10^(-6)/℃)make them expected to become the novel low temperature co-fired ceramics(LTCC).

低温共烧陶瓷(LTCC)技术在材料学上的进展

低温共烧陶瓷(LTCC)技术是近年发展起来的令人瞩目的整合组件技术,已经成为无源集成的主流技术,成为无源元件领域的发展方向和新的元件产业的经济增长点．本文叙述了低温共烧陶瓷技术(LTCC)的特点、制备工艺、材料制备相关技术和国内外研究现状以及未来发展趋势．

含钡玻璃陶瓷LTCC粉体的表面修饰及其对玻璃陶瓷性能的影响

为了降低BaO-TiO2-B2O3-SiO2玻璃陶瓷中钡离子的析出,通过化学沉淀法和硫酸处理法对玻璃陶瓷粉体进行了表面修饰,在玻璃陶瓷粉体的表面形成了一层不溶于水的无机膜(氧化铝或BaSO4),不仅阻断了LTCC中钡离子与水的接触途径,使LTCC玻璃陶瓷粉体制备可适用于水基流延工艺的浆料,且操作简便,无毒副作用。研究发现用共沉淀法包覆氧化铝对玻璃陶瓷的性能影响不大,但是硫酸包覆处理后大大提高了玻璃陶瓷的烧结温度,限制了LTCC的应用。

低固有烧结温度LTCC微波介质陶瓷研究进展

为了满足现代微波通信器件小型化和集成化发展的要求,必须开发出烧结温度低且能与Ag、Cu等价廉金属电极实现共烧兼容的微波介质陶瓷体系。重点介绍了Li基、Bi基、钨酸盐、磷酸盐和碲酸盐等低固有烧结温度的微波介质陶瓷体系,并总结了其在低温共烧陶瓷方面的研究进展。

基于LTCC技术的三维集成微波组件

低温共烧陶瓷(LTCC)技术和三维立体组装技术是实现微波组件小型化、轻量化、高性能和高可靠的有效手段.本文研究实现了基于LTCC技术的三维集成微波组件,对三维集成微波组件的立体互连结构、三维集成LTCC微波电路的垂直微波互连、微波多芯片模块(MMCM)的垂直微波互连等关键技术进行了重点阐述.研制出的三维集成微波组件的体积和重量分别比传统的二维平面LTCC集成微波组件减小40%和38%,电气性能相当.

基于LTCC技术的蓝牙巴伦设计

介绍了一种新型贴片式多层陶瓷巴伦。该巴伦是基于LTCC（Low Temperature Co-fired Ceramic,低温共烧陶瓷）技术设计的新型多层结构巴伦，采用独特的螺旋线宽边耦合带状线结构（SBCS），并且增加了端电容，极大地缩小了巴伦尺寸。设计的巴伦频率范围为2．4～2．5GHz，具有尺寸小、插损低、平衡度好等优点，并且工艺敏感度低，可应用于蓝牙通讯系统。文章讨论了其小型化思路与方案，描述了所设计巴伦的3D结构，给出了设计仿真结果与实验结果，两者吻合较好。

LTCC水基流延生带材料的制备与叠层性能

利用硼硅酸盐玻璃和氧化铝陶瓷复合制备了相对介电常数为7～9的LTCC材料粉体,利用苯丙乳液作为粘结剂,甘油作为增塑剂,成功制备出了浆料固含量高、稳定性好的水基流延浆料;该工艺制备的生带材料表面光滑,强度高,且容易在室温下叠层,经过850～900℃烧结,其相对体积密度最高可以达到96%以上;以上述LTCC生带为原材料,在室温条件下制备了烧结性能良好的叠层器件,具有很好的应用前景。