Design and Analysis of a Performance-Optimized CMOS UWB Distributed LNA

In this paper, the systematic design and analysis of a CMOS performance-optimized distributed low-noise amplifier (DLNA) comprising bandwidth-enhanced cascode cells will be presented. Each cascode cell employs an inductor between the common-source and common-gate devices to enhance the bandwidth, while reducing the high-frequency input-referred noise. The noise analysis and optimization of the DLNA accurately accounts for the impact of thermal noise of line terminations and all device noise sources of each CMOS cascode cell including flicker noise, correlated gate-induced noise and channel thermal noise on the overall noise figure. A three-stage performance-optimized wideband DLNA has been designed and fabricated in a 0.18-mum SiGe process, where only MOS transistors were utilized. Measurements of the test chip show a flat noise figure of 2.9 dB, a forward gain of 8 dB, and input and output return losses below -12 dB and -10 dB, respectively, across the 7.5 GHz UWB band. The circuit exhibits an average IIP3 of -3.55 dBm. The 872 mum times 872 mum DLNA chip consumes 12 mA of current from a 1.8-V DC voltage.     

Integrated circuit transmission-line transformer power combiner for millimetre-wave applications

A new approach for power combining several low-voltage CMOS amplifiers using a new on-chip transmission line transformer structure is presented. The power combiner utilises the interconnection of short sections of integrated differential lines and has an efficiency independent of the transformation ratio. Full-wave electromagnetic simulation confirms the operation and low insertion loss of the transformer     

Empirical equations for electrical conductivity and density of Zn,Cd and Mn sulphate solutions in the range of electrowinning and electrorefining electrolytes

Electrical conductivities and densities of acidic zinc, cadmium and manganese sulphate solutions were measured. Empirical equations have been derived to represent the measured values with high accuracy. Electrical conductivity of solutions has been shown to be expressed as a logarithmic function of temperature, a second order polynomial function of sulphuric acid concentration and a linear function of metal ion concentration. It can be deduced that the density of solution can be described as a linear function of metal ion concentration, temperature and sulphuric acid concentration. These equations could be used to improve the electrowinning or electrorefining process conditions.     

Electrochemical studies of zinc–cobalt alloy coatings deposited from alkaline baths containing glycine as complexing agent

Co-deposition of Zn–Co alloy coatings that were electrodeposited from weakly alkaline glycine solutions has been studied by cyclic voltammetry. Scanning electron microscopy (SEM), energy depressive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used to study surface morphology, chemical composition, and phase structure of the coatings. Corrosion behavior of the coatings was also studied using potentiodynamic polarization tests in 3.5 wt% NaCl solution. Cyclic voltammetry results showed that in Zn–Co deposition from an alkaline bath in the presence of glycine, cobalt deposited at a potential near to that of zinc together with successful co-deposition of Co and Zn. It was also shown that reduction–oxidation (redox) reactions of Zn–Co alloy deposits were quasi-reversible and resulted in deviation of electrodeposited alloys from the equilibrium phase diagrams. The corrosion resistance of the deposits was also highly influenced by the composition and morphology of the coatings. Overall, Zn–Co deposit containing 0.89 wt% Co showed that the highest corrosion resistance among the coatings that was due to its single phase structure and fine morphology.     

Analytical approximate solution of competitive facilitated transport of acid gases through liquid membranes

An analytical approximate solution for the competitive facilitation factor of components A and E across a liquid membrane is developed in the case of instantaneous reactions inside the liquid membranes. This analytical solution solves the dimensionless, nonlinear diffusion-reaction transport problem governing the competitive facilitated transport of two gaseous components through liquid membranes. Prediction of the facilitation factors has been obtained for the equilibrium chemical reaction regime, considering the unequal complexes diffusivities and cases of zero and nonzero permeate side solute concentrations. This mathematical solution leads to analytical expressions for the concentration profiles of the species across the liquid membrane. In comparison with the present numerical solution and also numerical calculations and experimental data from the open literature, the difference between the analytical predictions and those obtained from the numerical solution were found to be in well agreement.     

Code-modulated path-sharing multi-antenna receivers: theory and analysis

Conventional multi-antenna receiver front-ends require multiple RF/baseband chains and analog-to-digital converters (ADC). This increases power consumption and chip area substantially. In this letter, we introduce a new Code-Modulated Path-Sharing Multi-Antenna (CPMA) receiver architecture suitable for any multi-antenna scheme including spatial multiplexing, spatial diversity, and beamforming. The receiver uses code modulation to distinguish the antenna signals before combining them in the analog domain. The combined signal propagates through shared-path blocks and all the original signals are later recovered in the digital domain for further processing. Due to the spread spectrum nature of code modulation, a larger bandwidth is needed for the blocks in the shared path. To alleviate this effect, the use of non-orthogonal coding is examined. An effective channel matrix is derived and the system capacity is evaluated in terms of the cross-correlation between signature codes. Implementation and code selection issues are discussed. Analysis and simulation results indicate that by properly selecting non-orthogonal code sets, the spreading factor, and therefore, the overall analog signal bandwidth is reduced while incurring minimal performance degradation.     

Potential impacts of nanotechnology development in Iran

Industrialized countries have provided heavy funding for nanotechnology and made its development a priority. Some applications are entering the market and prominent scientists have assessed nanotechnology as a potentially wonderful phenomenon [1]. The worldwide investment in nanotechnology research and development (R&D) by government organizations has increased from $432 million in 1997 to about $4.1 billion in 2005 [2]. Several developing countries also have launched nanotechnology initiatives in order to exploit its benefits and sustain economic growth [3]. But the national issues and problems of developing countries are totally different from those of industrialized countries. Poverty, unemployment, inequality, and inability to fulfill basic needs are common problems in developing countries [4]. On the other hand, industrialized countries are faced with problems like aging populations, collapsing birth rates, unemployment, security issues, and cultural chaos [5]. There are also problems that are shared, such as environmental degradation, air and water pollution, exhaustion of natural resources, and incurable illnesses [3], [5]. From the beginning, nanotechnology pioneers have suggested they will solve these problems and that they will achieve social goals through nanotechnology's development [6]. In 2001, Iran also established a council for the development of nanotechnology and started formulating a nanotechnology development plan. The country faces both opportunities and threats with respect to nanotechnology. This article presents four possible scenarios for nanotechnology in Iran, and evaluates the effectiveness of these different strategies for nanotechnology development in the country.     

Coordinating and pricing decisions in two competitive reverse supply chains with different channel structures

This paper addresses coordination and competition problem in two reverse supply chains each having its own exclusive retailer and manufacturer. The chains have various collecting channel structures so that one of them uses the advantages of dual channels, where the consumer can return their e-waste through direct or traditional channels, while its competitor collects obsolete products only through its traditional channel. The willingness to return in each channel is a function of self- and cross-discounts of the competitors. Four decision scenarios are investigated; the first and second chain respectively select, Decentralised-Decentralised, Centralised-Centralised, Centralised-Decentralised or Decentralised-Centralised scenario. The closed-form optimal solution of each channel is derived based on the Stackelberg game when the second chain acts as a leader. The most economical scenario is determined by using a Non-Zero-Sum game when each chain plays as a single player in the game. To coordinate the members’ decisions and to convince unsatisfied members, two coordination contracts are offered. Numerical investigations reveal that direct channel suggests more discount and obtains more share of market. The results show that Centralised-Centralised scenario is the best decision from the SCs’ perspective which proposing contracts are able to persuade members to change their strategy to a global decision.