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Imaging through opacity is proposed based on auto-modulated multimode fiber speckle illumination. The imaging resolution is improved by making use of the intrinsic characteristics of the speckle illumination and a localization strategy.

A self-modulated coherent random fiber laser is proposed for both memory-effect-based imaging and ghost imaging, filling the gap that the two imaging scenarios haven’t been realized using a same light source.

A novel S-band antenna is proposed in this paper. The antenna consists of two layers of radiant dipole. The unit is capable of realizing broad beam-width of 144° in E-plane with isolation better than -35dB between two ports. The circular polarization can be achieved by exciting two ports with equal amplitude and 90° phase difference. Moreover, the axial ratio is less than 2dB in the antenna operating frequency band. At last, a triangular grid array with 64 elements is designed. The simulated results show that the designed array can meet the requirements of large scanning angle. It can be applied for the fifth generation mobile communications (5G) Multiple-Input Multiple-Output (MIMO)base station.

This article presents a fully integrated quadrature cross-coupled voltage controlled oscillator (QVCO) using common-drain transistor instead of common-source transistor as a coupling device.The prototype 3.8 GHz QVCO in 0.18 μm CMOS process is proposed to generate four output phases and it uses two p-core cross-coupled VCOs and nMOS coupling devices. The proposed QVCO oscillates from 3.6 to 3.84 GHz and the power consumption is 7.24 mW at 0.74 V supply voltage. The measured phase noise is –126.19 dBc/Hz at 1 MHz offset frequency from the carrier frequency 3.745 GHz. The VCO occupies a chip area of 1.08 ×0.924 mm2 and provides a figure of merit of –189.05 dBc/Hz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1262–1266, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27578

This article proposes a high-performance CMOS voltage-controlled oscillator (VCO) implemented with composite right-/left-handed nonmobius-connected LC-rings to provide dual-band differential outputs.The VCO consists of two cross-coupled sub-VCOs sharing series-LC resonators. nMOSFET switches are used to control high- and low-band outputs. The proposed VCO has been implemented with the TSMC 0.18 μm SiGe BiCMOS technology. The die area of the VCO is 1.16 × 1.12 mm2. With the switch on, the odd-mode VCO operates at the high-frequency 6 GHz band, and when the switch is off, the even-mode VCO operates at the low-frequency 4 GHz band. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:468–471, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27375

In order to investigate the enhanced control and operation of wind power generation systems based on doubly-fed induction generators (DFIG) when grid voltage is unbalanced, a novel phase-locked loop system used to realize real time phase synchronization is presented. With the help of the novel PLL, the phase of positive sequence component can be obtained quickly and accurately, even if the grid voltage appears to be unbalanced and distorted. As a result, the rapidity and stability of PLL are greatly improved. The simulation and experiment results have verified the validity and effectiveness of it under the unbalanced and distorted grid voltage.

A wholly aromatic polypyrene was synthesized by direct chemical oxidative polymerization of pyrene with ferric chloride as oxidant in hexane/nitromethane. Successful synthesis of polypyrene was thoroughly confirmed by IR, UV/Vis, 1D (1)H NMR, 2D (1)H-(1)H COSY, 2D (1)H-(13)C HSQC, MALDI-TOF MS, elemental analysis, and X-ray diffraction methods. The results indicated that the polypyrene was formed mainly through dehydro coupling between 2- or 1- and 2'- or 1'-positions on pyrene rings having a degree of polymerization of around 24. The polypyrene was purified and then separated into THF-soluble (ca. 10 %) and THF-insoluble (ca. 90 %) fractions. Compared with insulating pyrene monomer, the polypyrene is a controllably conducting polymer that has low conductivity of 3.4x10(-8) S cm(-1) in its virgin state, moderate conductivity of 2.28x10(-4) S cm(-1) upon iodine doping, but much higher conductivity of up to 81.2 S cm(-1) after the insoluble polypyrene was heated up to 1300 degrees C in nitrogen with a high char yield of 70.6 %. In particular, the soluble polypyrene demonstrates much stronger visible color fluorescence and much lower toxicity than pyrene. The soluble polypyrene would be advantageous for detecting Fe(3+) with almost no interference of other metal ions. The soluble and insoluble polypyrene fractions have potential applications as intrinsically luminescent and highly conducting carbon materials, respectively.