High Efficiency and Light Mobile Electronic Business System Based on Mobile Agent Middleware

With the development of wireless network, many people want to carry out commerce activity because of its convenience and mobility. It is necessary to build high efficiency and collaborative transaction system due to high delay and burst error in wireless network. Unfortunately, it is difficult for traditional technology to achieve high efficiency in low bandwidth network and new technology is expected. Large analysis of collaborative commerce system shows that there are some common design elem…     

A 3.1–10.6 GHz UWB LNA Based on Self Cascode Technique for Improved Bandwidth and High Gain

In this work, we present a self cascode based ultra-wide band (UWB) low noise amplifier (LNA) with improved bandwidth and gain for 3.1–10.6 GHz wireless applications. The self cascode (SC) or split-length compensation technique is employed to improve the bandwidth and gain of the proposed LNA. The improvement in the bandwidth of SC based structure is around 1.22 GHz as compared to simple one. The significant enhancement in the characteristics of the introduced circuit is found without extra passive components. The SC based CS–CG structure in the proposed LNA uses the same DC current for operating first stage transistors. In the designed UWB LNA, a common source (CS) stage is used in the second stage to enhance the overall gain in the high frequency regime. With a standard 90 nm CMOS technology, the presented UWB LNA results in a gain \(\hbox {S}_{21}\) of \(20.10 \pm 1.65\,\hbox {dB}\) across the 3.1–10.6 GHz frequency range, and dissipating 11.52 mW power from a 1 V supply voltage. However, input reflection, \(\hbox {S}_{11}\), lies below \(-\,10\) dB from 4.9–9.1 GHz frequency. Moreover, the output reflection (\(\hbox {S}_{22}\)) and reverse isolation (\(\hbox {S}_{12}\)), is below \(-\,10\) and \(-\,48\) dB, respectively for the ultra-wide band region. Apart from this, the minimum noise figure (\(\hbox {NF}_{min}\)) value of the proposed UWB LNA exists in the range of 2.1–3 dB for 3.1–10.6 GHz frequency range with a a small variation of \(\pm \,0.45\,\hbox {dB}\) in its \(\hbox {NF}_{min}\) characteristics. Linearity of the designed LNA is analysed in terms of third order input intercept point (IIP3) whose value is \(-\,4.22\) dBm, when a two tone signal is applied at 6 GHz with a spacing of 10 MHz. The other important benefits of the proposed circuit are its group-delay variation and gain variation of \(\pm \,115\,\hbox {ps}\) and \(\pm \,1.65\,\hbox {dB}\), respectively.     

Design of 50–70 GHz Planar Wideband Bandpass Filter on Liquid Crystal Polymer Substrate

In this paper, the authors propose a novel and compact 50-70 GHz planar microstrip bandpass filter, possessing sharp-rejection, low insertion-loss and wide-band characteristics, based on Liquid Crystal Polymer (LCP) substrates. The filter is fabricated on LCP substrates by using standard processing technologies. The proposed filter exhibits a return loss level better than 10 dB, an insertion loss of 5 dB and a 3-dB bandwidth of 30%.The measured and simulated results show good agreement, proving that LCPs are potential and very promising materials for flexible millimeter-wave substrate applications.     

AlGaN Nanostructures with Extremely High Room-Temperature Internal Quantum Efficiency of Emission Below 300 nm

We present theoretical optimization of the design of a quantum well (QW) heterostructure based on AlGaN alloys, aimed at achievement of the maximum possible internal quantum efficiency of emission in the mid-ultraviolet spectral range below 300 nm at room temperature. A sample with optimized parameters was fabricated by plasma-assisted molecular beam epitaxy using the submonolayer digital alloying technique for QW formation. High-angle annular dark-field scanning transmission electron microscopy confirmed strong compositional disordering of the thus-fabricated QW, which presumably facilitates lateral localization of charge carriers in the QW plane. Stress evolution in the heterostructure was monitored in real time during growth using a multibeam optical stress sensor intended for measurements of substrate curvature. Time-resolved photoluminescence spectroscopy confirmed that radiative recombination in the fabricated sample dominated in the whole temperature range up to 300 K. This leads to record weak temperature-induced quenching of the QW emission intensity, which at 300 K does not exceed 20% of the low-temperature value.     

Wideband Millimeter-Wave Channel Characterization in an Open Office at 26 GHz

Based on the newest frequency allocation for the fifth generation (5G) radio systems at 26 GHz millimeter wave band by the World Radio Communications Conference, this paper investigates the wideband channel properties by measurements carried out in the LOS and NLOS environments at 26 GHz with 1 GHz bandwidth in an open office at KeySight Beijing, China, which is a representative of an indoor hotspot scenario. In the time domain measurements, an omni-directional biconical horn is used at the transmitter, while at the receiver a 24.3 dBi horn is applied and rotated with 5° angular step in the whole azimuth plane, and from ?20° to 30° in the elevation plane with 10° angular step. In the work, two kinds of path-loss models are developed, namely directional and omni-directional models by using close-in and float intercept methods. The directional path-loss model is useful for adopting beamforming techniques. The large scale channel parameters such as the shadow fading, root mean square (RMS) delay spread, RMS angular spread in the azimuth and elevation planes, Ricean K-factor, number of clusters and their correlations are investigated for the fifth generation (5G) link and system level simulations. A new method for extracting number of clusters is proposed to find the peak power within a sliding window. The power angular profiles are employed at the measurement locations for propagation mechanisms studies. We believe that the newest results in this work are useful in the simulations and planning for future 5G radio systems at 26 GHz.     

Monolithic Integrated Circuits Based on Gallium Nitride for Short-Range Radar and Communications in the 22–25 GHz Frequency Range

Russian Microelectronics - A set of monolithic integrated circuits (MICs) in the 22–25 GHz range based on gallium nitride nanoheterostructures on sapphire substrates is designed, produced,...     

An Indoor Propagation Model Based on a Novel Multi Wall Attenuation Loss Formula at Frequencies 900 MHz and 2.4 GHz

This paper describes an indoor propagation model pertaining to a sample of six different multi-floor building structures that have a stone block type outer wall and are generally described as university, hospital and office type buildings. Those flat roofed, stone built, multi floor buildings are very common, not only in Palestine, but probably in vast areas in the Middle East region. The goal is to come up with a relatively general model that would be both reliable and representative to a wider sample of multi-floor buildings, falling under a similar building structure classification. The improved model; we name the AMATA model, lends itself to its generalization for the GSM and wireless LAN frequencies as well as the developed multiwall effective attenuation fourth power nonlinear equation that solely relies on the number of wall separations within the floor. A clear improvement in the standard deviation of the mean path loss resulted in comparison to the well known indoor ITU path loss model. Our model can be applied with a high confidence level to the wider range of buildings similar to the classification type of the building structure sample, we conducted measurements upon.     

Terahertz MMICs and Antenna-in-Package Technology at 300 GHz for KIOSK Download System

Toward the realization of ultra-fast wireless communications systems, the inherent broad bandwidth of the terahertz (THz) band is attracting attention, especially for short-range instant download applications. In this paper, we present our recent progress on InP-based THz MMICs and packaging techniques based on low-temperature co-fibered ceramic (LTCC) technology. The transmitter MMICs are based on 80-nm InP-based high electron mobility transistors (HEMTs). Using the transmitter packaged in an E-plane split-block waveguide and compact lens receiver packaged in LTCC multilayered substrates, we tested wireless data transmission up to 27 Gbps with the simple amplitude key shifting (ASK) modulation scheme. We also present several THz antenna-in-packaging solutions based on substrate integrated waveguide (SIW) technology. A vertical hollow (VH) SIW was applied to a compact medium-gain SIW antenna and low-loss interconnection integrated in LTCC multi-layer substrates. The size of the LTCC antennas with 15-dBi gain is less than 0.1 cm³. For feeding the antenna, we investigated an LTCC-integrated transition and polyimide transition to LTCC VH SIWs. These transitions exhibit around 1-dB estimated loss at 300 GHz and more than 35 GHz bandwidth with 10-dB return loss. The proposed package solutions make antennas and interconnections easy to integrate in a compact LTCC package with an MMIC chip for practical applications.     

A High Performance 0.18μm RF nMOSFET with 53GHz Cutoff Frequency

阐述了0.18μm射频nMOSFET的制造和性能. 器件采用氮化栅氧化层/多晶栅结构、轻掺杂源漏浅延伸结、倒退的沟道掺杂分布和叉指栅结构. 除0.18μm的栅线条采用电子束直写技术外，其他结构均通过常规的半导体制造设备实现. 按照简洁的工艺流程制备了器件，获得了优良的直流和射频性能：阈值电压0.52V，亚阈值斜率80mV/dec，漏致势垒降低因子69mV/V，截止电流0.5nA/μm，饱和驱动电流458μA/μm，饱和跨导212μS/μm (6nm氧化层，3V驱动电压）及截止频率53GHz.     

High Voltage Breaker Current Monitoring and FaultDiagnosis System Based on Fiber Current Sensor

Abstract: The current measuring principle, the hardware structure and the software functions of a high voltage breaker current monitoring and fault diagnosis system are introduced. A simple algorithm for calculating the current effective value is given. The cut - off characteristics of the breaker are classified. This system can provide a foundation for reasonably determining the breaker service period.     

Technology for Producing Schottky Contacts Based on an IrSi–Si Composite

Russian Microelectronics - In this study, in order to obtain Schottky contacts based on an IrSi–Si composite, n- and p-type silicon wafers doped, respectively, with boron and phosphorus with...     

Frequency Dependent Capacitance and Conductance–Voltage Characteristics of Nitride GaAs Schottky Diode

Semiconductors - A nitride GaAs Schottky diode have been fabricated by nitridation of GaAs substrates with thickness 0.7 nm of GaN layer. The capacitance–voltage C(V) and...     

High Voltage Breaker Current Monitoring and Fault Diagnosis System Based on Fiber Current Sensor^①

The current measuring principle,the hardware structure and the software functions of a high voltage breaker current monitoring and fault diagnosis system are introduced.A simple algorithm for calculating the current effective valus is given.The cut-off characteristics of the breaker are classified.This system can provide a foundation for reasonably determining the breaker service period.     

Performance Test of CW 300 GHz Gyrotron FU CW I

A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kV and the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE_22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B _c at the cavity is adjusted at a proper value. However, within a range of B _c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes.     

On the Use of Radiometric Measurements to Estimate Atmospheric Attenuation at 100 and 300 GHz

At frequencies of between 100 GHz and 30 THz, propagation conditions are severely affected by the influence of the composition and phenomena of the troposphere. This paper focuses on the use of radiometric measurements to estimate attenuation at 100 and 300 GHz, considering non-scattering scenarios, in which the main contributions are given by atmospheric gases and non-rainy clouds. These techniques allow the estimation of the absorption loss through the entire atmosphere, without the need for a signal source situated in a satellite or a high altitude aircraft. On the basis of well-accepted absorption models, the results of calculating gaseous, cloud, and total attenuation using 3-year meteorological data from Madrid, Spain, are detailed, as well as estimates of the expected values of the sky brightness temperature as measured by the radiometer. Finally, based on the results obtained, a discussion on the use of radiometric measurements at both frequencies is presented, in connection with an experimental campaign currently under preparation.     

Design of Track/Hold （T/H） Circuit of Broad Bandwidth and High Speed Pipeline Structure ADC Based on the Super Frequency Application

A track/hold （T/H） circuit of broad bandwidth high speed pipeline structure ADC based on the super frequency application is designed in the paper. Some main factors affecting SNR of high speed ADC, such as aperture uncertainty, switch capacitor, and MOS switch, are analyzed. In the circuit, the full-differential structure and the bottom plate sampling technique are adopted to optimize the switch capacitors and MOS switches. The result based on the Spectre simulation on 0.35pm Bi- CMOS technology indicate that the aperture uncertainty, charge-injection, and non-linearity of clock feed-through are considerably restrained and the performance of T/H circuit is enhanced     

A Novel High Output Resistance Current Source Based on Negative Resistance

给出一种利用等效负电阻实现阻抗增加的方法.利用该方法,文中所提出的电流源可在不增加电源电压的前提下显著提高其输出阻抗.基于0.6μm的CMOS工艺模型,仿真所得电流源的输出阻抗可达109Ω,同时,该电流源频带宽度为1.04GHz,在-40～145℃之间,电流源的温度系数只有10.6ppm/℃.     

Performance Analysis of Tags Collection Time on A New Architecture of 2.4 GHz Embedded Active RFID System for Indoor and Outdoor Tracking and Monitoring Applications Based on IEEE 802.15.4 Standard

This paper focuses on the analysis of tags collection time of 2.4 GHz embedded active Radio Frequency Identification (RFID) system for indoor and outdoor real-time tracking and monitoring applications based on IEEE 802.15.4 standard. The main novelty of the system is the implementation of the communication method in order to provide Machine to Machine (M2M) communication and automated switching mechanism between indoor and outdoor location by utilizing active RFID, Wireless Sensor Network (WSN), Global Positioning System (GPS) and mobile communication on a single platform. In this work, GPS receiver covers outdoor location tracking, while active RFID provides identification and Receive Signal Strength Indicator (RSSI) reading for each tag holder to cover indoor location tracking especially near or inside building where location information is not detected by GPS. Several experiments were conducted on three different RFID tags which were active RFID tag embedded with GPS and GSM (ERFIDG2), active RFID tag embedded with GPS (ERFIDG) and standalone RFID tag communicating with the same active RFID reader. The experiment was done to evaluate the communication performance of the active RFID in terms of tags collection time using Transparent (AT) and Application Programming Interface (API) mode. The experiment was extended to measure tags collection time in single hop and multi hops communication for Tag Talk First (TTF) and Reader Talk First (RTF) protocols. The results show that the proposed active RFID system (ERFIDG2) is better than the standalone and ERFIDG systems. The in-depth research done in this work is to study the experience and identify the challenges that will be faced in the development and implementation of a wireless RFID-based system for tracking and monitoring applications.     

Comparative Analysis of the Electroluminescence Efficiency in Type-I and Type-II Heterostructures Based on III–V Narrow-Gap Compounds

Semiconductors - We study in detail the mechanisms of radiative and Auger recombination in type-I and type-II heterostructures based on III–V narrow-gap materials. The presence of a...