Wireless Energy Transfer System with Multiple Coils via Coupled Magnetic Resonances

A general equivalent circuit model is developed for a wireless energy transfer system composed of multiple coils via coupled magnetic resonances. To verify the developed model, four types of wireless energy transfer systems are fabricated, measured, and compared with simulation results. To model a system composed of n‐coils, node equations are built in the form of an n‐by‐n matrix, and the equivalent circuit model is established using an electric design automation tool. Using the model, we can simulate systems with multiple coils, power sources, and loads. Moreover, coupling constants are extracted as a function of the distance between two coils, and we can predict the characteristics of a system having coils at an arbitrary location. We fabricate four types of systems with relay coils, two operating frequencies, two power sources, and the function of characteristic impedance conversion. We measure the characteristics of all systems and compare them with the simulation results. The flexibility of the developed model enables us to design and optimize a complicated system consisting of many coils.     

16‐QAM‐Based Highly Spectral‐Efficient E‐band Communication System with Bit Rate up to 10 Gbps

This paper presents a novel 16‐quadrature‐amplitude‐modulation (QAM) E‐band communication system. The system can deliver 10 Gbps through eight channels with a bandwidth of 5 GHz (71‐76 GHz/81‐86 GHz). Each channel occupies 390 MHz and delivers 1.25 Gbps using a 16‐QAM. Thus, this system can achieve a bandwidth efficiency of 3.2 bit/s/Hz. To implement the system, a driver amplifier and an RF up‐/down‐conversion mixer are implemented using a 0.1 µm gallium arsenide pseudomorphic high‐electron‐mobility transistor (GaAs pHEMT) process. A single‐IF architecture is chosen for the RF receiver. In the digital modem, 24 square root raised cosine filters and four (255, 239) Reed‐Solomon forward error correction codecs are used in parallel. The modem can compensate for a carrier‐frequency offset of up to 50 ppm and a symbol rate offset of up to 1 ppm. Experiment results show that the system can achieve a bit error rate of 10^?5 at a signal‐to‐noise ratio of about 21.5 dB.     

Small‐Size and High‐Isolation MIMO Antenna for WLAN

A small‐sized (15 mm×30 mm) planar monopole MIMO antenna that offers high‐isolation performance is presented in this letter. The antenna is miniaturized using inductive coupling within a meander‐line radiator and capacitive coupling between a radiator and an isolator. High isolation is achieved by a T‐shaped stub attached to the ground plane between two radiators, which also contributes to the small size using a folded structure and the capacitive coupling with radiators. The proposed antenna operates for the WLAN band within 2.4 GHz to 2.483 GHz. The measured isolation (S₂₁) is about –30 dB, and the envelope correlation coefficient is less than 0.1.     

Bandwidth‐satisfied routing in multi‐rate MANETs by cross‐layer approach

Previous quality‐of‐service (QoS) routing protocols in mobile ad hoc networks (MANETs) determined bandwidth‐satisfied routes for QoS applications. Since the multi‐rate enhancements have been implemented in MANETs, QoS routing protocols should be adapted to exploit them fully. However, existing works suffer from one bandwidth‐violation problem, named the hidden route problem (HRP), which may arise when a new flow is permitted and only the bandwidth consumption of the hosts in the neighborhood of the route is computed. Without considering the bandwidth consumption to ongoing flows is the reason the problem is introduced. This work proposes a routing protocol that can avoid HRP for data rate selection and bandwidth‐satisfied route determination with an efficient cross‐layer design based on the integration of PHY and MAC layers into the network layer. To use bandwidth efficiently, we aim to select the combination of data rates and a route with minimal bandwidth consumption to the network, instead of the strategy adopted in the most previous works by selecting the combination with the shortest total transmission time. Using bandwidth efficiently can increase the number of flows supported by a network. Copyright 2010 John Wiley & Sons, Ltd.     

光电着降导引系统的跟踪和参数测量

分析和研究了CCD摄影测量算法的精确定位技术,建立了4个信标点空间位置坐标的数学模型,并推导出计算公式,该算法的特点是计算精度高,可实时计算空间目标的坐标位置,从而对空间目标精确定位,在航天、航空技术上有重要的用途.设计了一台直升机着降与回收的光电导引系统,利用2台红外CCD对在直升机两侧机身被半导体激光器照明的4个信标成像,通过对图像的处理和目标识别,提取出信标的位置和恣态信息.使用双摄影测量法模型实时计算出直升机相对于着降点的坐标.使用高性能的DSP系统,实时检测和跟踪双通道图像信号并显示出实验结果.模拟实验结果表明,在8～13m距离内,光电引导系统的距离测量精度达到±5cm,而角度测量精度达到±3°.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

基于FPGA的32位浮点加法器的设计

在综合分析各种浮点加法器算法的基础上,提出了一种符合TI格式标准的32位浮点加法器,同时兼顾了速度和面积两方面因素.本设计在virtex-4系列FPGA上进行了实现,最高速度可达到182.415MHz,资源占用也较为合理.     

图3-着色问题的O(2n)链数DNA计算机算法

随着DNA计算的不断发展,如何克服穷举算法带来的指数爆炸问题已成为DNA计算领域的重要研究目标之一．为减少图3-着色问题DNA计算机算法中的DNA链数,本文将Adleman—Lipton模型生物操作与粘贴模型解空间相结合的DNA计算模型进行扩展,通过设计顶点着色器、稀疏图／稠密图搜索器,提出一种用于求解图3-着色问题的DNA计算模型与算法．将本算法与同类算法对比分析表明：本算法在保持多项式操作时间的条件下,将求解n个顶点的图3-着色问题所需DNA分子链数从O（3^n）减少至O（2^n）,改进了3-着色问题同类文献的研究结果．     

SON技术是降低网络成本和提高网络效率的利器

介绍了SON技术的目的和主要特征,指出了自规划、自配置、自优化和自恢复的主要功能以及在标准上的主要进展,最后提出了SON技术实施所面临的5个挑战和主要对策建议。     

(Na_(1/2)Bi_(1/2))TiO_3-SrTiO_3无铅压电陶瓷的介电、压电性能

研究了 (Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系无铅压电陶瓷的介电、压电性性。Sr2 的引入对 NBT材料的常温介电系数、铁电相与反铁电相转变温度 TF A(180°C)以及居里温度 TC(30 0°C)的影响都不大 ,但却较大幅度地降低了 NBT材料的高矫顽场 ,从而使极化相对容易。(Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系的压电性能参数 d33和 kt分别达到 10 0 p C/N和 0 .45