Bandwidth, SAR, and efficiency of internal mobile phone antennas

This paper presents a thorough investigation into the effects of several phone chassis-related parameters-length, width, thickness, and distance between the head and phone-on the bandwidth, efficiency, and specific absorption rate (SAR) characteristics of internal mobile phone antennas. The studied antenna-chassis combinations are located beside an anatomical head model in a position of actual handset use. The effect of the user's hand is also studied with two different hand models. The main part of the study is based on FDTD simulations, but also experimental results, which support the computationally obtained conclusions, are given. The presented analysis provides novel and useful information for future design of mobile handset antennas. The results show the general trends of bandwidth, SAR, and efficiency with different chassis parameters. The results also reveal a connection between these three performance parameters: an increase in SARs and a decrease in radiation efficiency occur compared to the general trend when the bandwidth reaches its maximum. This happens when the resonant frequency of the chassis equals that of the antenna.     

Experimental investigation of waveguide components designed on the basis of EBG structures

Several basis components of a waveguide circuit designed on the basis of a planar waveguide with a 2D lattice of metal cylinders are investigated. These components include a regular waveguide, coupled waveguides, a short-circuited waveguide, and waveguide irregularities in the form of metal cylinders. Experimental and theoretical results are presented and compared. The theoretical analysis is based on the method of compensating sources. Good agreement between theoretical and experimental results is demonstrated.     

对打击利用移动电话犯罪的探索

近年来，随着公众移动通信及其增值业务的发展，一些不法商人通过群发诈骗、六合彩短信及打诈骗电话等非法手段骗取广大消费者钱财。广东省各地市无线电管理机构，特别是中山市无线电管理机构．多次配合公安部门和移动通信运营商监测非法话务情况．缴获手机及群发器600多部。下面笔者总结一些打击利用移动电话犯罪的方法及经验，与各位无线电管理同行分享。     

错误观念妨碍电量计在智能手机中的应用

本文通过分析几种错误观念简要介绍了电池电量计在智能手机中的应用,并针对无线数据业务重点阐述了其不可低估的附加价值。     

Performance enhancement of a compact wideband patch antenna array using EBG structures

In this paper, a compact wideband linear microstrip phased array antenna (MPAA) is proposed. To reduce the size of MPAA, a compact wideband aperture coupled microstrip patch antenna (MPA) is utilized as array element. Size reduction of the array element is performed through incorporating an interdigital capacitor (IDC) in the patch and a metamaterial (MTM) unit cell close to slot in the ground plane of the antenna. By cutting two vertical slits from the slot, further compacting of the slot in the ground plane of array element is obtained. By this technique dimensions of the patch and slot are reduced by 12.9% and 12.2%, respectively. Furthermore, dimensions of the MPAA are reduced through decreasing the spacing between array elements causing the antenna performance degradation. To overcome this shortage and improve the radiation characteristics of the proposed MPAA, an electromagnetic bandgap structure (EBG) is utilized. The effect of implementing EBG cells on the reflection coefficient of the elements in the MPAA during beam scanning is studied in details. The maximum measured gain, bandwidth and cross-polarization level of the fabricated MPAA are 13.3 dBi, 24.4% and −40 dB, respectively making it a good candidate for monopulse tracking radar applications. The measurement results confirm the simulation results.     

手机病毒移动互联网网络封堵

随着移动互联网的发展,手机用户面临越来越多的安全风险,大量的手机病毒不断的危害客户的利益,如何有效的对手机病毒进行监测治理,本文介绍了目前一些常用的方法,并根据移动公司网络的实际情况提出了一种有效的解决方案,在互联网出口部署一套分布式封堵系统,系统能够对病毒URL进行自动封堵,有效治理手机病毒,保护移动用户,提升客户感知。     

Compressed sensing method for human activity recognition using tri-axis accelerometer on mobile phone

The diversity in the phone placements of different mobile users' dailylife increases the difficulty of recognizing human activities by using mobile phone accelerometer data. To solve this problem, a compressed sensing method to recognize human activities that is based on compressed sensing theory and utilizes both raw mobile phone accelerometer data and phone placement information is proposed. First, an over-complete dictionary matrix is constructed using sufficient raw tri-axis acceleration data labeled with phone placement information. Then, the sparse coefficient is evaluated for the samples that need to be tested by resolving L1 minimization. Finally, residual values are calculated and the minimum value is selected as the indicator to obtain the recognition results. Experimental results show that this method can achieve a recognition accuracy reaching 89.86%, which is higher than that of a recognition method that does not adopt the phone placement information for the recognition process. The recognition accuracy of the proposed method is effective and satisfactory.     

Motivations for using the mobile phone for mass communications and entertainment

This study draws on the uses and gratifications framework to examine expanded use of a hybrid medium—the mobile phone—for mass communications and entertainment. Results of a telephone survey of 208 users show different motivations predict diverse uses of the mobile phone. Instrumental use motives drive the use of the mobile phone for news-seeking and Web-surfing. Further, the motive of pass time is significantly linked to playing video games via the mobile phone. In addition, the high-tech mobile phone enabled users to be more active: the more intensively people use mobile phones for voice calls, the more likely they will be to use mobile data services. Thus, the hybrid mobile phone bridges interpersonal and mass communication. Finally, younger users are more likely to use mobile phones for getting news and entertainment. Implications for the industry and recommendations for future research are discussed.     

手机病毒与移动通信安全

目前手机在日常生活中使用得越来越广泛.尤其是随着移动通信技术向3G/B3G的迅猛演进,手机的功能也越来越强大.但是与此同时,手机病毒也已经开始对移动通信系统构成严峻威胁.本文阐述了手机病毒原理、攻击方式、主要类型以及手机病毒的预防措施等几个方面的问题.同时针对手机病毒所带来的威胁,对整个移动通信安全机制的改进和完善提出了建议.     

手机病毒与移动通信安全

目前手机在日常生活中使用得越来越广泛。尤其是随着移动通信技术向3G／B3G的迅猛演进．手机的功能也越来越强大。但是与此同时．手机病毒也已经开始对移动通信系统构成严峻威胁。本文阐述了手机病毒原理．攻击方式、主要类型以及手机病毒的预防措施等几个方面的问题。同时针对手机病毒所带来的威胁．对整个移动通信安全机制的改进和完善提出了建议。     

手机CE认证

手机产品要出口到欧洲国家或地区进行销售,手机产品必须贴有CE标志。只有经过CE认证的产品才能贴有CE标志,没有经过CE认证以及贴上CE标志,是不能在欧洲市场上销售的。通过深入了解CE的认证知识,熟悉CE认证相关的R＆TTE测试标准,以及EMC、SAR、RF、SAFETY四类测试内容,熟悉CE认证的整个流程,才能顺利地通过CE认证、加快CE认证的进度以及减少CE认证的费用。通过实际的手机CE案例对如何准备CE样机、相关技术文档以及需要注意的事项进行了详细说明。     

基于手机产品的SMT编程

在民营SMT制造业中,使用GC-PowerStation对Gerber、CAD、BOM资料的处理,得到数据和图形融合一体的文件。该文件导出基准点与元件坐标(处于同一坐标系)的组合CAD数据,可有效解决元件贴片坐标校正难题,大幅降低换线调机时间及难度,提高换线效率。从Gerber提取的基准点相对坐标是保证绝大部分元件贴片坐标无需校正的关键因素。     

基于手机的声学超宽带室内定位

针对室内定位技术部署复杂、成本高的问题,提出了一种利用手机接收声学信号通过脉冲压缩进行室内定位的方法。通过借鉴雷达系统中的脉冲压缩技术,将信号和噪声分离,并提取出信号到达时延估计。为了减小定位误差,研究了手机的声学特性,设计了声学超宽带信号的信道模型,将应答节点时延回传,进一步减小信号传播的时延估计。在停车场的试验结果表明：定位结果和实际位置相符,平均定位误差在30 cm以内。     

Toward an interactive poster using digital watermarking and a mobile phone camera

A method for embedding a watermark in print media, posters or other paper printouts and reading the watermark information blindly with a camera phone is proposed. A subtractive-additive embedding method is applied in which the message is coded with a directed periodic pattern. The message is detected and read by searching regularities in the autocorrelation function of a periodic signal. The robustness to disturbance occurring during printing process due to air interface and camera phone properties is ensured using noise reduction, modified JND model, enhanced peak detection with filtering and shaping and two-level coding of the message. The validity of the approach is proven with tests, and an application example of an interactive poster is examined.     

对象全景技术在安卓手机上的实现

文中提出了一种快捷制作对象全景图并在安卓手机上展示的方法。该方法首先在不同距离和俯仰角度围绕对象拍摄几段视频,然后根据相似度删除冗余帧,提取不同角度的图片,大大减少了拍摄照片的工作量。进一步将所提取的不同角度和距离的图片依次排列成矩阵,通过手机屏幕人机交互按钮依次查看,实现对象全景的展示。     

智能手机操作系统开源软件使用的法律问题

2G时代,我国移动通信市场长期受制于国外厂商,作为移动通信核心技术的三大部分：网络技术制式标准、终端硬件、终端操作系统,无一例外被国外商业巨头垄断,如高通、诺基亚、微软等公司。随着我国拥有自主知识产权的TD—SCDMA技术制式标准的应用和相关产业的推进,国内厂商在打破外国公司技术和市场垄断上有了长足的进步,除拥有了自主知识产权的3G网络技术制式标准,     

基于智能手机的移动学习系统开发技术研究

移动学习逐步成为成人远程教育重要的学习方式,本文针对开发基于智能手机的移动学习系统,在探讨移动学习及其网络架构的基础上,采用实例分析法,对现阶段开发移动学习系统的各种技术进行了分析,重点剖析了现阶段开发移动学习系统的开发模式及其技术架构的实现。这些技术和方法,对技术人员进行移动学习系统的开发具有指导和借鉴意义。     

智能手机电磁辐射研究

智能手机逐步普及,许多人机不离手,随之产生的电磁辐射问题逐渐引起人们的注意.本文对4G模式下不同品牌不同型号的手机在不同状态下的电磁辐射进行测量,得出减少电磁辐射,保证身体健康的建议.     

手机病毒防治方法及其发展趋势分析

首先介绍了手机病毒的基本概念和发展历史,然后重点探讨了手机病毒的防治方法、并对其发展趋势进行了深入的分析。