On the circular polarization operation of annular-ring microstripantennas

Circular polarization (CP) operation of an annular-ring microstrip antenna with a pair of inserted slits at its fundamental TM₁₁ mode is proposed and experimentally investigated. Two examples of the proposed antenna fed using a microstrip line at the inner and outer patch boundaries are studied. Results show that the proposed antenna can have good CP performance and, moreover, the required antenna size at a fixed CP operation can be much less than that of a conventional circularly polarized circular microstrip antenna operated at the TM₁₁ mode. Details of the proposed antenna for CP operation are described and experimental results of the CP performance are presented and discussed     

Compact circularly-polarised circular microstrip antenna withcross-slot and peripheral cuts

Novel compact circular-polarisation (CP) operation of a circular microstrip antenna, with a cross-slot in the patch centre and a pair of peripheral cuts at opposite sides of the patch boundary, is proposed and experimentally studied. For operation at a fixed frequency, the proposed antenna using a single probe feed, can have an antenna size reduction of ~20% as compared to regular size CP operation of a circular microstrip antenna. Details of the experimental results are presented and analysed     

Printed dual-band dipole antenna with U-slotted arms for 2.4/5.2 GHz WLAN operation

Dual-band operation of a printed dipole antenna with U-slotted arms is presented. Due to the embedded U-shaped slots, two additional dipole arms are obtained in the proposed design, which form a second dipole antenna with a smaller length and which can generate a higher resonant mode for the 5.2 GHz band operation. By incorporating the original dipole arms designed for the 2.4 GHz band operation, the proposed antenna can perform WLAN operations in the 2.4 and 5.2 GHz bands.     

Internal Patch Antenna With a Thin Air-Layer Substrate for GSM/DCS Operation in a PDA Phone

A thin dual-band internal patch antenna for Global System for Mobile Communication, 890-960 MHz/Digital Communication System, 1710-1880 MHz (GSM/DCS) operation in a Personal Digital Assistant (PDA) phone is presented. The antenna can generate two wide resonant modes for GSM (890-960 MHz) and DCS (1710-1880 MHz) operation, yet it requires an air-layer substrate of thickness 4 mm only, which is among the thinnest internal mobile phone antennas that have been reported. The antenna's top patch comprises a resonant narrow strip supporting a longer resonant path for GSM operation and a resonant subpatch supporting a shorter resonant path for DCS operation. By including a suitable widened end portion for the narrow strip and a suitable tapered end portion for the subpatch, increased bandwidths for the proposed thin internal mobile phone antenna are obtained. Detailed design considerations of the proposed antenna are described. In addition, the user's hand effects on the performances of the proposed antenna are studied     

An Improved Utility Interface for Microturbine Generation System With Stand-Alone Operation Capabilities

In this paper, an alternative filter and control approach for the design of a microturbine's utility interface is proposed. The new method employs a unified current-regulated controller to drive the system converter as a power conditioner for the grid-tied operation and an emergent generator for the stand-alone operation, where few current sensors are required to serve the controller for both operating modes. The proposed method had been examined under various scenarios, including the loss of grid and parallel operation. The results help consolidate the feasibility and practicability of the approach for the applications considered     

面向服务的网络管理机制的建模方法

针对目前以面向对象的方法描述的网络管理机制仅仅关注管理操作细节的局限性,该文提出以服务的概念建模网络管理机制,扩展了对操作机制的商务过程特性、流程和策略等方面内容的描述能力。首先,通过建立网络管理功能、商务过程元素以及网络管理服务三者间的对应关系,使网络管理服务兼具操作细节和商务过程两方面的内容。然后,提出了包括服务接口、信息、语义、流程和策略的网络管理服务描述内容以及一种自顶向下和自底向上相结合的网络管理服务分析过程,并进行了举例说明。以面向服务的方法描述网络管理操作机制,符合面向客户和商务过程的电信运营策略,支持自动和灵活的运营过程,并可以有效指导网络管理及运营支撑系统的分析、设计、实施和集成。     

基于时序数据的云网协同平台人工智能运维体系

云计算在企业应用中的拓展不但表现为平台规模的拓展,也表现为平台应用的延伸。“云网协同”和“微服务化”是当前企业云平台演进的重要趋势。随着企业信息化建设重要性的持续提升,微服务化云网协同平台的运行维护面临极大挑战。首先分析了平台运维面临的挑战,梳理了平台人工智能运维需求,提出了基于时序数据分析的平台人工智能运维技术体系,并给出了云网协同平台人工智能运维子系统参考设计。所提技术体系和系统设计具有实用性和推广性,可以作为企业云平台建设和优化的技术途径参考。     

基于逆序层优先的柔性综合调度算法

针对以往柔性综合调度算法均考虑正向调度,导致需要考虑目标工序的多紧前工序约束条件,难以合理安排相关工序进而影响产品完工时间的问题,该文提出一种基于逆序层优先的柔性综合调度算法。首先,提出逆序层优先策略,将各工序分配至逆序层待调度工序集;其次,提出动态拟长路径策略,确定各逆序层待调度工序集中工序的调度顺序;然后,分别提出设备选择策略和设备抢占策略以确定目标工序的加工设备以及加工时间;最后,提出基于完工时间翻转的调度方案转换策略,将逆序调度方案转换为正序调度方案。实例表明,和已有主流算法相比,该算法在不提高算法复杂度的前提下能够缩短产品完工时间。     

基于ITIL架构的高校一卡通运维管理体系的研究

为了使高校一卡通有一个有效的运维管理体系参考模型,以便实现运维的流程化和规范化,从高校一卡通系统的实际运维管理出发,分析了一卡通运维管理的现状,指明了存在的问题。借鉴并拓展了ITIL理论与方法,提出了组织结构和规章制度的建设,构建了基于ITIL理论的一卡通运维管理体系。今后可作为一卡通运维管理的参考模型,来优化运维服务,提高一卡通运维管理水平。     

电力信息通信数据智能运维技术分析研究

针对现有电力信息通信数据运维技术存在资源耗比较高、容量低的问题,提出一种电力信息通信数据智能运维技术.分析电力信息通信数据特征,构建电力信息通信数据智能运维模型;通过FCM算法对日志数据进行分类,获得数据智能运维日志分类结果,设计运维资源耗比预测算法;采用最小二乘法拟合直线方程计算数据运维容量,实现了电力信息通信数据的...     

Circularly Polarized Square Ring Slot Antenna with Arrow‐Shaped Structure

A novel design of a compact square‐ring slot microstrip antenna for achieving circular polarization (CP) operation is proposed and experimentally studied. By using an arrow‐shaped slot structure as a radiating element, the resonant frequency of the proposed antenna is significantly lowered, which can lead to a large size reduction for fixed frequency operation. The CP radiation characteristics are achieved by loading with proper asymmetry, which can be placed diagonally. A prototype of the proposed design is implemented and its performance is measured. Measured results show that radiation patterns with good CP characteristics are obtained at the resonant frequency.     

New start-up schemes for isolated full-bridge boost converters

Two new start-up schemes for isolated full-bridge boost converters are proposed in this paper. The control timing for each scheme, which is compatible with pulse-width modulated (PWM) control timing for normal boost mode operation, are investigated. Design considerations on the relationship between the turns ratios of the boost choke windings and the main transformer windings, and its effects on the operation of the converter, are studied. The two proposed start-up schemes are experimentally verified on a 1.6 kW, 12 V/288 V prototype.     

电吸收调制器和DFB激光器一种改进的双有源层堆积集成方法

提出了一种改进型的双有源层堆积方法制作单片集成电吸收调制的DFB激光器,报道了器件的制作过程和主要性能,初步结果为:阈值电流38mA,激光器在100mA下出光功率4.5mW左右,调制器消光比约9dB(从+0.5V到-3.0V).对比此前国外报道的具有常规双量子阱堆层结构的器件结果(出光功率仅1.5mW),我们制作的器件的出光功率有了明显的提高.     

Continuously Tunable Microwave Photonic Filter With Negative Coefficients Using Cross-Phase Modulation in an SOA-MZ Interferometer

A notch filter with negative tap is proposed based on exploiting cross-phase modulation in a semiconductor optical amplifier Mach-Zehnder interferometer. This configuration shows a high operation bandwidth and reduces the chirp of the modulated signal compared to prior proposed configurations based on cross-gain modulation. We compare the operation of the structure when optic delay lines or dispersive fibers are used to generate the optical taps. Moreover, a continuous free-spectral range tuning is shown.     

基于FPGA的FFT处理器设计

在火车车轮的振动式擦伤检测系统中,经常需要对振动信号进行频谱分析,为实现振动频谱信号的及时输出,在此根据FFT算法中的一种变形运算流图,提出一种基于FPGA的FFT流水线结构,总结了利用流水线结构实现这种FFT运算流图的数据存取规律,并按此结构利用Verilog语言设计了64点数据的6级流水线运算结构。利用振动信号测试数据进行仿真实验,结果表明该设计方法的正确可靠。     

Integrable Current-Mode Filter Realisation using Dual-Output Current Conveyors for Low-Frequency Operation

The realisation criteria of continuous-time current-mode (CM) active filters for low frequency operation are investigated. New lossless and lossy integrators for low frequency operation using dual-output current conveyors (DO-CCII) are proposed. Basing on these building blocks, a CM universal filter with low natural frequencies suitable for integrated circuit implementation is presented. Using the proposed filter, natural frequencies as low as a few ten hertz can be achieved on an integrated circuit chip without using any external passive components. The proposed circuit simultaneously produces three basic filter responses at its high impedance outputs and it has good passive and active sensitivity performance.     

High-Voltage Analog System for a Mobile NAND Flash

High-voltage analog circuits, including a novel high-voltage regulation scheme, are presented with emphasis on low supply voltage, low power consumption, low area overhead, and low noise, which are key design metrics for implementing NAND Flash memory in a mobile handset. Regulated high voltage generation at low supply voltage is achieved with optimized oscillator, high-voltage charge pump, and voltage regulator circuits. We developed a design methodology for a high-voltage charge pump to minimize silicon area, noise, and power consumption of the circuit without degrading the high-voltage output drive capability. Novel circuit techniques are proposed for low supply voltage operation. Both the oscillator and the regulator circuits achieve 1.5 V operation, while the regulator includes a ripple suppression circuit that is simple and robust. Through the paper, theoretical analysis of the proposed circuits is provided along with Spice simulations. A mobile NAND Flash device is realized with an advanced 63 nm technology to verify the operation of the proposed circuits. Extensive measurements show agreement with the results predicted by both analysis and simulation.     

Novel compact circularly polarized square microstrip antenna

A novel compact circular-polarization (CP) operation of the square microstrip antenna with four slits and a pair of truncated corners is proposed and investigated. Experimental results show that the proposed compact CP design can have an antenna-size reduction of about 36% as compared to the conventional corner-truncated square microstrip antenna at a given operating frequency. Also, the required size of the truncated corners for CP operation is much greater than that for the conventional CP design using a simple square microstrip patch, providing a relaxed manufacturing tolerance for the proposed compact CP design. Details of the experimental results are presented and discussed     

Low-power high-speed phase frequency detector based on carbon nano-tube field effect transistors

A phase frequency detector (PFD) with a very low dead zone is proposed which is based on a configuration adaptable to both CMOS or carbon nano-tube transistors (CNTFETs). In the first step the proposed configuration is designed using CMOS transistors, and then CNTFETs are substituted to improve the speed and reduce the propagation delay. The proposed PFD in addition to very low dead zone, has low power consumption and high frequency range of operation, which are achieved as a result of the elimination of the reset path. The simulation results based on 32 nm technology for CNTFET and 180 nm technology for CMOS, illustrate that CNTFET-based proposed circuit dissipates 2 µW and has frequency of operation up to 30 GHz, and the dead zone equal to 1 ps. Compared to the conventional PFD based on CMOS technology, its dead zone and power consumption are lower. In addition, the effects of blocks’ parameters including the phase detector, which affect the operation of the phase locked loop, or delay locked loop, are systematically analyzed.

     

电吸收调制器和DFB激光器一种改进的双有源层堆积集成方法

提出了一种改进型的双有源层堆积方法制作单片集成电吸收调制的 DFB激光器 ,报道了器件的制作过程和主要性能 ,初步结果为 :阈值电流 38m A ,激光器在 10 0 m A下出光功率 4 .5 m W左右 ,调制器消光比约 9d B(从+0 .5 V到 - 3.0 V) .对比此前国外报道的具有常规双量子阱堆层结构的器件结果 (出光功率仅 1.5 m W) ,我们制作的器件的出光功率有了明显的提高 .