World Academy of Science, Engineering and Technology, International Journal of Electronics and Communication Engineering 

About: World Academy of Science, Engineering and Technology, International Journal of Electronics and Communication Engineering is an academic journal. The journal publishes majorly in the area(s): Wireless sensor network & Antenna (radio). Over the lifetime, 146 publications have been published receiving 345 citations.

Solving the Wireless Mesh Network Design Problem using Genetic Algorithm and Simulated Annealing Optimization Methods

Abstract: Mesh clients, mesh routers and gateways are components of Wireless Mesh Network (WMN). In WMN, gateways connect to Internet using wireline links and supply Internet access services for users. Multiple gateways are needed, which take time and cost budget to set up, due to the limited wireless channel bit rate. WMN is a highly developed technology that offers to end users a wireless broadband access. It offers a high degree of flexibility contrasted to conventional networks; however, this attribute comes at the expense of a more complex construction. Therefore, a challenge is the planning and optimization of WMNs. This paper concentrates on the challenge using a genetic algorithm and simulated annealing. The genetic algorithm and simulated annealing enable searching for a low-cost WMN configuration with constraints and determine the number of used gateways. Experimental results proved that the performance of the genetic algorithm and simulated annealing in minimizing WMN network costs while satisfying quality of service. The proposed models are presented to significantly outperform the existing solutions.

Novel Approach to Design of a Class-EJ Power Amplifier Using High Power Technology

Abstract: This article proposes a new method for application in communication circuit systems that increase efficiency, PAE, output power and gain in the circuit. The proposed method is based on a combination of switching class-E and class-J and has been termed class-EJ. This method was investigated using both theory and simulation to confirm ∼72% PAE and output power of >39dBm. The combination and design of the proposed power amplifier accrues gain of over 15dB in the 2.9 to 3.5GHz frequency bandwidth. This circuit was designed using MOSFET and high power transistors. The loadand source-pull method achieved the best input and output networks using lumped elements. The proposed technique was investigated for fundamental and second harmonics having desirable amplitudes for the output signal. Keywords—Power Amplifier (PA), GaN HEMT, Class-J and Class-E, High Efficiency.

Detection and Tracking Approach Using an Automotive Radar to Increase Active Pedestrian Safety

Abstract: Vulnerable road users, e.g. pedestrians, have a high impact on fatal accident numbers. To reduce these statistics, car manufactures are intensively developing suitable safety systems. Hereby, fast and reliable environment recognition is a major challenge. In this paper we describe a tracking approach that is only based on a 24 GHz radar sensor. While common radar signal processing loses much information, we make use of a track-before-detect filter to incorporate raw measurements. It is explained how the Range-Doppler spectrum of pedestrian can help to initiate and stabilize tracking even in occultation scenarios compared to sensors in series.

A New Microstrip Diplexer Using Coupled Stepped Impedance Resonators

Abstract: This paper presents a new structure of microstrip band pass filter (BPF) based on coupled stepped impedance resonators. Each filter consists of two coupled stepped impedance resonators connected to microstrip feed lines. The coupled junction is utilized to connect the two BPFs to the antenna. This two band pass filters are designed and simulated to operate for the digital communication system (DCS) and Industrial Scientific and Medical (ISM) bands at 1.8 GHz and 2.45 GHz respectively. The proposed circuit presents good performances with an insertion loss lower than 2.3 dB and isolation between the two channels greater than 21 dB. The prototype of the optimized diplexer have been investigated numerically by using ADS Agilent and verified with CST microwave software. Keywords—Band Pass Filter, coupled junction, coupled stepped impedance resonators, diplexer, insertion loss, isolation.

Charge-carrier-mobility-dependent-open-circuit-voltage-in-organic-and-hybrid-solar-cells

Abstract: A better understanding of the open-circuit voltage () related losses in organic solar cells (OSCs) is desirable in order to assess their photovoltaic performance. We have derived as a function of charge carrier mobilities (and) for organic and hybrid solar cells by optimizing the drift-diffusion current density. The thus obtained depends on the energy difference between the highest occupied molecular orbital (HOMO) level and the quasi-Fermi level of holes of the donor material and on the ratio of the electron () and hole () mobilities in the blend. It is found that the increases with the increase of the mobility ratio. The most loss in is contributed by the energetics of the donor and acceptor materials.