射频识别标签天线的按需微喷射制备

基于数字化微喷射技术搭建了射频识别(RFID)标签天线的按需微喷射制备系统。首先,将纳米银导电墨水按需微喷射到镀有疏水化薄膜的聚对苯二甲酸乙二醇脂(PET)基底表面形成天线图形;然后在恒温干燥箱内烧结,形成RFID标签天线。实验研究了微喷射系统参量对液滴产生的影响以及制备参数对纳米银导线成线的影响,制得了最小线宽为100μm、厚度为2.8μm、电阻率为5.2μΩ·cm且阻值具有较好线性度的导线。设计、仿真和制备了弯折偶极子天线,并对其性能参数进行了测试,结果显示其天线谐振频率、带宽和谐振点S11参数等与仿真结果具有较好的一致性。实验结果表明,按需微喷射导电银墨水制备RFID标签天线的方法具有系统结构简单、成本较低、液滴微喷射精确、便于制备任意天线图形等特点;制备的弯折偶极子天线尺寸可控、导电性高、阻值均一性好,并具有较好的天线性能。     

织物表面微滴喷射反应成形导电线路基础研究

针对织物表面导电线路制备工艺复杂、导线宽度受限、成本高、柔性差等问题,提出微滴喷射与化学反应相结合的织物表面导电线路成形的方法。利用开发的气动式双喷头微滴喷射系统,对硝酸银和抗坏血酸溶液进行稳定喷射试验研究;在此基础上,以棉织物为基板,进行点阵和不同基板运行速度导线沉积试验,对成形导线线宽和方阻进行测量及微观形貌观察。结果表明,该喷射系统能够实现两种溶液的按需喷射和定点沉积反应,且沉积反应成形点阵尺寸均匀,产物主要为银颗粒;线宽和方阻测量结果及SEM照片表明,随着基板运行速度的增大,导线线宽先增大后减小,反应生成的银颗粒数量先增多后减少,导线的方阻均值和标准偏差先减小后增大;且在0.40 mm/s时,成形导线均匀性较好,生成的银层较为致密,方阻均值和标准偏差为最小。     

喷射打印和化学沉积成形微细电路中微滴可控喷射研究

针对智能纺织品中微细线路制备工艺复杂、成本高、柔性差等问题,提出了喷射打印与化学沉积技术相结合制作微细线路的方法。利用构建的气动式微滴喷射系统,以100μm的喷嘴对抗坏血酸和硝酸银溶液进行了可控稳定喷射及沉积成形试验。试验获得了两溶液可控稳定喷射的工艺参数,且微滴在基板上沉积的点阵均匀、成形线宽基本一致,成形银线具有一定导电性。     

陶瓷浆料按需喷射打印沉积系统设计与实验

针对陶瓷零件脆性大、硬度高、复杂形状受限、生产周期长、成本高等问题,提出了一种将微滴按需喷射技术应用到陶瓷零件打印成形的新方法。通过分析陶瓷浆料按需喷射打印沉积成形工艺原理,完成了试验系统总体结构、喷射装置和运动控制系统的设计开发,并利用该系统进行了陶瓷浆料单个微滴按需喷射,以及点阵、线条、平面和实体的打印沉积实验。实验结果表明:该系统可满足陶瓷浆料微滴的按需喷射和打印成形,验证了所开发的按需喷射打印系统的可行性与正确性。     

气动式微滴喷射过程仿真与尺寸均匀性试验研究

为使气压驱动式微滴喷射装置能产生均匀的微滴和稳定的喷射过程,使用FLUENT建立了二维轴对称计算模型并对微喷过程进行了模拟仿真。研究了气压驱动式微滴按需产生过程及腔体内压力峰值对单颗微滴成形的影响规律,利用构建的喷射系统对水进行喷射试验,并对产生微滴的均匀性进行了研究。仿真获得了单颗微滴的成形过程并得到了腔体内较低压力峰值有利于提高微喷稳定性的结论。实验结果表明,产生的微滴附着直径最大变化率为1.82%,均匀性较好。     

气压驱动金属微熔滴可控喷射及沉积精度分析?

金属微滴按需喷射成形制造中,保证喷射系统按需产生均匀微滴和喷射沉积的位置精度是成形高质量金属零件的关键。采用试验研究的方法,分析喷嘴壁附着杂质对稳定喷射以及工艺参数对微滴均匀性的影响,并对喷射系统在可控喷射情况下按需产生的锡铅合金(Sn60%Pb40%)微滴尺寸分布进行分析;研究沉积高度变化对微滴沉积精度的影响。在上述研究基础上,通过选择合适的沉积高度,沉积制造一个6×6微滴阵列,并对微滴阵列的沉积精度进行分析。结果表明,所产生微滴的平均直径为321μm,尺寸标准偏差为2.897μm,约99%的颗粒分布在平均直径±2.8%附近区间内,分布较集中,均匀性较好;得到了发散距离随沉积高度增加而增大的变化趋势;成形的微滴阵列精度满足制造要求。为后续成形高质量微小金属零件提供必要的基础。     

基板倾斜角度对3D打印微滴成形形貌的影响研究

为研究微滴喷射3D打印过程中基板倾斜角度对微滴成形形貌的影响,以低熔点铅锡合金为研究对象,通过实验和仿真研究微滴分别与0°、15°、30°、45°、60°倾角的基板碰撞动力学特性及微滴形貌成形规律。结果表明,基板倾角对微滴铺展的对称性和形貌有着主要影响,随着倾角的增大,微滴铺展的不对称性也随之增大。在一定倾斜角范围内,微滴与基板碰撞后铺展程度变化不大,微滴沿壁面滑移距离变化较为平均,随着倾斜角增大到一定程度,铺展程度变化显著,滑移距离变化较大;微滴的惯性力对微滴碰撞前期的变形影响较大,微滴成形后期其形貌主要受张力、应力和粘性力的影响。     

基于机器学习的按需式电流体喷射打印微滴直径预测

为节省按需式电流体微滴喷射打印技术的微滴直径预测时间及解决众多工艺参数的合理选择问题，实现更高打印质量和效率，提出了数值仿真与机器学习算法相结合的方法。基于线性回归、支持向量回归、神经网络和随机森林算法建立8种参数与微滴直径的关系模型。算法结果表明：支持向量回归算法准确率最高、误差较小，随机森林算法和线性回归算法次之，神经网络算法准确率较低且误差较大。机器学习可以对按需式电流体微滴喷射打印微滴直径进行有效预测，此方法可以有效地提高设计效率。     

一种适于柔性RFID标签生产的微胶滴检测算法

根据柔性射频识别（RFID）标签批量生产装备对点胶质量严格控制的需求,提出了一种基于胶滴二维图像信息的点胶质量在线检测算法。该算法通过差分、滤波去噪和Blob分析等图像处理过程所得的胶滴图像获取胶滴二维信息,再依据胶滴的面积等参量对点胶质量进行评价。对不同基板和点胶量柔性RFID标签生产进行实际测试实验,实验结果显示,该算法适应性较好、胶滴尺寸波动较小,可对点胶一致性作出定量评价与分析。     

均匀液滴喷射成形中微熔滴关键参数在线检测系统

为了在均匀液滴喷射成形中实现对微熔滴直径、喷射速度及偏转距离的在线检测,提出了基于机器视觉的微熔滴关键参数在线检测方法.利用双缓冲技术设计了图像采集处理流程,提出了微熔滴图像预处理及关键参数测量算法.将检测系统应用于均匀液滴喷射成形过程中,得到了微熔滴直径与激振频率、喷射速度与喷射压强、偏转距离与充电电压之间的关系.检测结果表明,测量值与理论计算值吻合较好,相对标准偏差(RSD)均不超过5.9%,为零构件的精确成形提供了必要保证.     

一种激光全息RFID双重防伪电子标签设计

介绍了一种激光全息射频识别(RFID)双重防伪电子标签的设计方法,并通过理论分析和电磁仿真,研究了激光全息膜对无源RFID天线射频性能的影响规律。在此基础上设计了一款共面倒F天线,并应用于无源RFID标签,且制作了样品。测试结果表明,使用该天线的激光全息RFID标签能达到较好的读取效果,并且受激光全息膜的影响较小。     

Inkjet-printed passive UHF RFID tags: review and performance evaluation

In this paper, the performance and the feasibility of inkjet-printed dipole RFID tag antennas are experimentally studied in the implementation of identifying objects with different electromagnetic properties. To estimate the performance quality, we compare our results to those obtained using traditional etched copper dipole tag antennas. We first examine the performance characteristics, i.e. the read range and the radiation patterns, of tags in free space. Then we attach the tags directly to target objects and compare the optimum performance on target objects to that of the tag in free space. The obtained results provide information about the behaviour of inkjet-printed tag antennas on different objects. This information can be used to optimize the inkjet-printed tag antenna performance for use on objects with different characteristics.     

Characterization of UHF RFID tags fabricated directly on convex surfaces by pad printing

The possibility of pad printing in RFID tag antenna manufacturing is investigated. Passive UHF RFID tags were printed on flat and on convex surfaces with two different polymer thick-film silver inks. The effect of the ink and substrate material properties on tag antenna performance was examined. The goal was to provide information which is needed in adapting the pad-printing technique in RFID tag manufacture. The results show that pad printing is suitable for tag manufacturing on flat and on convex surfaces. The curvature of the substrate did not significantly affect the tag performance. It was more important to take into consideration other substrate properties, ink characteristics, morphology, and printing parameters. The best practice is to take these matters into consideration in the initial tag design process to ensure proper tag performance at the desired frequency.     

Effects of size and shape of metallic objects on performance of passive radio frequency identification

Passive ultra high frequency (UHF) spectrum radio frequency identification (RFID) systems have numerous applications. Continuous research and development of RFID systems is carried out to study solutions for different challenging cases of identification. Metallic objects set challenges for identification due to the behavior of electromagnetic waves on conductive boundaries. Therefore, novel tag designs have been developed for identification of metallic objects. This article presents a performance comparison of two different metal-mountable tag antennas, which are printed inverted-F antenna (IFA) and microstrip patch antenna with photonic band gap (PBG) ground plane and with regular ground plane. The effects of size and shape of metallic objects on tag antenna performance are studied with read range measurements and compared between the tag antenna types.     

Radio frequency technology for automated manufacturing and logistics control. Part 2: RFID antenna utilisation in industrial applications

The trend in industrial automation is to move towards fast and real-time identification, further improving the high-level of accuracy that is needed to enable continuous identification and monitoring. The interest in adopting radio frequency identification (RFID) technology for use in automation systems with minimal manual involvement is increasing rapidly. RFID systems are capable of providing real-time object visibility with high accuracy enabling continuous identification and location of all items and thereby providing accurate real-time data management instead of simple snapshots. In this paper, the use of multiple reader antennas is examined against collision and interference avoidance. Also, antenna operation is studied in typical industrial environments containing metallic objects or other conducting surfaces. In addition, this paper reviews different tag antennas and their characteristics for particular item identification cases. These cases include items made of specific materials that obstruct or prevent radio wave propagation by either absorbing or reflecting them. The results given in this paper are fully applicable with practical RFID solutions.     

射频电子标签天线设计及印刷工艺分析

阐述了基于13．56MHz射频印刷标签天线具体的设计方法和制造工艺。以ICODE芯片为例,描述了整个标签天线结构设计方法,设计并印刷出天线。通过对印刷天线的分析,进而得出印刷天线电感及电容的获得主要取决于设计结构的结论,而对印刷工艺而言,印刷工艺的优化目标之一则是获得较低的天线阻值,从而得到较高的天线品质因子Q,获得理想的天线综合性能,满足感应距离的需要。     

Radio Frequency Technology for Automated Manufacturing and Logistics Control. Part 1: Passive RFID Systems and the Effects of Antenna Parameters on Operational Distance

Identification plays an important role in automation. In the near future radio frequency identification (RFID) will be an option for mass production automation projects. RFID represents a contactless method for data transfer in object identification. Generally, RFID systems consists of three components: 1. A small electronic data carrying device called a transponder, or a tag that is attached to the item to be identified. 2. A reader or a scanner that communicates with the tag by using radio frequency signals. 3. A host data processing system that contains information on the identified item and distributes information to other remote data processing systems. An RFID system can be considered as a wireless communication system because the scanner communicates with the tag by using electromagnetic waves at radio frequencies. The performance of this communication link can be studied by determining the read range for backscatter RFID systems. The read range, or the distance at which the reader unit notices the tag, depends on many factors. Several parameters, e.g. the frequency used for identification, the gain, the orientation and the polarisation of the reader antenna and the transponder antenna, and the placement of the tag on the object to be identified, will all have an impact on the RFID system read range. In this paper, Part 1, we focus on presenting an overview of different passive RFID systems and the read range of the backscatter RFID system. The function of frequency, antenna gain and polarisation mismatch are analysed and discussed. In Part 2, several manufacturing automation cases of different natures will be presented. These cases contain a selection of requirements for an RFID system and they are analysed using the information presented in this paper.     

信号源内置式球形偶极子天线新进展及应用

电磁兼容EMC（Electromagnetic Compatibility）领域所关心的频率范围从几十赫兹直到几十吉赫兹,在这么宽的频率范围内做试验,如果使用窄带天线,那么覆盖这么宽频率范围的天线数量将是不可接受的,所以在电磁兼容试验当中使用的天线一般都是宽频带天线。球形偶极子天线就是一种新型的小型宽频带天线,信号源内置使其无需外部引线独立工作,具有很大的工程应用价值。通过对球形偶极子辐射天线的产生机理进行进一步分析,结合实验室早期的研制工作改进了现有基频30 MHz的球形偶极子辐射天线,并在此基础上研制出以5 MHz、100 MHz为基频的球形偶极子辐射天线,扩展了应用的频带。     

介质透镜操控光电导天线辐射太赫兹波的研究

飞秒激光驱动的太赫兹 (terahertz, THz) 光电导天线是THz时域谱系统中常用的THz源,受全向辐射模式的影响,该光电导天线的天线主瓣小,方向性差。对波束的有效操控将有助于提高光电导天线的发射效率。以低温生长的砷化镓 (LT-GaAs) 作为天线基底材料,通过电磁仿真软件CST对蝶形天线辐射THz波的电磁分布特性进行仿真,研究了介质透镜对蝶形天线辐射出的THz波的操控。通过对透镜扩展厚度的理论与数值分析,得出一定频率下的最佳透镜扩展厚度值。仿真结果表明：随着频率的提高,蝶形天线在加载更小扩展厚度的硅透镜时可获得更好的方向性。