Initial and boundary conditions in multidimensional wave digital filter algorithms for plate vibration

Recently, multidimensional wave digital filter (MDWDF) structures have been proposed for the modeling of plate vibration problems. In this paper, we discuss how initial and boundary conditions may be properly embedded into such an algorithm in terms of the state quantities that are an integral part of the algorithm. Due to the essential feature of fully-local interconnectivity in the MDWDF model, different types of boundary conditions can be easily satisfied in a very simple and efficient manner. Instead of remodifying the whole algorithm, usually required by finite elements based methods, boundary conditions in terms of state outputs are simply attached to the model. This feature is especially useful when dealing with the mixed-edges boundary conditions frequently encountered in practice. Graphical results obtained from implementing the MDWDF algorithm are given to further demonstrate the capacities of the method in efficiently handling a fourth-order Mindlin plate vibration system with various types of boundary conditions.     

A 1.2 GHz programmable DLL-based frequency multiplier for wireless applications

A CMOS local oscillator using a programmable delayed-lock loop based frequency multiplier is present in this paper. The maximum measured output frequency is 1.2 GHz. The frequency of the output clock is 8/spl times/ to 10/spl times/ of an input reference clock between 100 to 150 MHz at simulation. No LC-tank is used in the proposed design such that the power dissipation as well as the active area is drastically reduced. The design is carried out by TSMC 1P5M 0.25 /spl mu/m CMOS process at 2.5 V power supply. The average lock time is optimally shortened by initializing the start-up voltage of the voltage-controlled delay tap line at the midway of the working range. Meanwhile, the power dissipation is 52.5 mW at 1.2 GHz output.     

A full-wave mixed potential mode-matching method for the analysisof planar or quasi-planar transmission lines

A full-wave mixed potential mode-matching method is presented for the analysis of planar and/or quasi-planar transmission lines. The transmission lines studied consist of layered (stratified) and nonlayered dielectric substrates and metal strips of finite thickness. The y-directed hybrid transverse electric (TE) and transverse-magnetic (TM) Hertzian potentials, perpendicular to the interfaces between each layered region, are employed in the layered regions. The nonlayered regions consist of dielectric step discontinuities that destroy the layered configuration in the horizontal plane, allowing a systematic and easy to handle full-wave formulation of the transmission line problem. The relative convergence criterion needs to be satisfied to obtain accurate electromagnetic field solutions. Theoretical results are in very good agreement with published data for various transmission line structures. Applications of the formulation to the proximity effects of microstrip and microslab lines are illustrated     

Characterization of the Ultrathin HfO2 and Hf-Silicate Films Grown by Atomic Layer Deposition

The physical properties of HfO₂ and Hf-silicate layers grown by the atomic layer chemical vapor deposition are characterized as a function of the Hf concentration and the annealing temperature. The peaks of Fourier transform infrared spectra at 960, 900, and 820 cm_-1 originate from Hf-O-Si chemical bonds, revealing that a Hf-silicate interfacial layer began to form at the HfO₂/SiO ₂ interface after post deposition annealing process at 600 degC for 1 min. Moreover, the intensity of the peak at 750 cm^-1 can indicate the degree of crystallization of HfO₂. The formed Hf-silicate layer between HfO² and SiO² is also confirmed by X-ray photoelectron spectroscopy     

4.9-GHz low-phase-noise transformer-based superharmonic-coupled GaInP/GaAs HBT QVCO

The low-phase-noise GaInP/GaAs heterojunction bipolar transistor (HBT) quadrature voltage controlled oscillator (QVCO) using transformer-based superharmonic coupling topology is demonstrated for the first time. The fully integrated QVCO at 4.87GHz has phase noise of -131dBc/Hz at 1-MHz offset frequency, output power of -4dBm and the figure of merit (FOM) -198dBc/Hz. The state-of-the-art phase noise FOM is attributed to the superior GaInP/GaAs HBT low-frequency device noise and the high quality transformer formed on the GaAs semi-insulating substrate.     

Performance enhancement of III–V compound multijunction solar cell incorporating transparent electrode and surface treatment

To enhance the performance of tandem‐type III–V compound multijunction solar cells, the transparent indium‐tin‐oxide (ITO) film was used to replace conventional metal electrode for increasing the incident light area. For performing ohmic contact between the n‐AlInP window layer and the ITO film, a transition layer of Au/AuGeNi thin metals was used and investigated. Besides, to improve ohmic performance and to passivate the surface states, (NH₄)₂S_x surface treatment was used. The conversion efficiency of the (NH₄)₂S_x‐treated triple‐junction solar cells was increased more than 3.09%. Furthermore, an improved oblique SiO₂/SiO₂/ITO triple antireflection structure was designed to reduce the reflectivity of illuminating sunlight. The conversion efficiency of the (NH₄)₂S_x‐treated triple‐junction solar cell with improved antireflection structure could be improved more than 4.23%. Simple and effective approaches were designed to improve the performances of tandem‐type III–V triple‐junction solar cells. Copyright © 2010 John Wiley & Sons, Ltd.     

An authenticated re‐encryption scheme for secure file transfer in named data networks

With the fast progress of the Internet and communication technologies, the digital communication is increasingly based on the architecture of TCP/IP. Nevertheless, in TCP/IP's architecture, there are limitations such as data uncertainty and flow overloading. In response to this, a novel architecture has been proposed, which is known as the named data network (NDN). Named data network is an alternative network architecture based on the data each user accesses. Users gain accesses to the data by using an adjacent router (node) that verifies the correctness of the data. In NDN, the router has the capability to store and search for the data. Hence, this architecture largely improves the disadvantages in TCP/IP's architecture. Named data network is a new proposal and relatively under‐researched now. Thus far, an adequate secure file transfer protocol is still unavailable for NDN. In some cases, files are broken or the source fails to authenticate, which results in the need to discover the owner of the file. Furthermore, we believe that NDN should involve an authentication mechanism in the secure file transfer protocol. In view of the above, this paper presents an authenticated re‐encryption scheme for NDN, which offers sender authentication, data confidentiality, and support for potential receivers. Finally, we also propose a security model for sender authentication and prove that the proposed scheme is secure.     

Stress Power Dependent Self-Heating Degradation of Metal-Induced Laterally Crystallized n-Type Polycrystalline Silicon Thin-Film Transistors

Using a fluorinated high-k/metal gate stack combined with a stress relieved preoxide (SRPO) pretreatment before high-k deposition, we show significant device reliability and performance improvements. This is a critical result since threshold voltage instability may be a fundamental problem, and performance degradation for high-fc is a concern. The novel fluorinated Ta_infinC_y/HfZrO_infin/SRPO gate stack device exceeds the positive-bias-temperature-instability and negative-bias-temperature-instability targets with sufficient margin and has electron mobility at 1 MV/cm comparable to the industrial high-quality polySi/SiON device on bulk silicon.     

Bidirectional Transmission Using Tunable Fiber Lasers and Injection-Locked Fabry–PÉrot Laser Diodes for WDM Access Networks

We propose and demonstrate the use of fiber ring lasers and Fabry-Perot laser diodes (FP-LDs) for wavelength-division-multiplexing access networks. The fiber ring laser not only generates downstream data traffic but also serves as the wavelength-selecting injection light source for the FP-LD located at the subscriber site. Moreover, it is wavelength tunable and can be applied to dynamic wavelength assignment networks. The ring laser has a tunable range of 30 nm in the C-band and a power fluctuation smaller than 0.6 dB. For 10-Gb/s downstream and 1.25-Gb/s upstream transmissions over 10-km single-mode fiber, power penalties less than 0.9 and 0.5 dB are demonstrated, respectively. A 40-dB sidemode suppression ratio is obtained for the FP-LD injection-locking at 1544.8 nm.