Smart Antennas and Intelligent Sensors Based Systems: Enabling Technologies and Applications

open access articleThe growing communication and computing capabilities in the devices enlarge the connected world and improve the human life comfort level. The evolution of intelligent sensor networks and smart antennas has led to the development of smart devices and systems for real-time monitoring of various environments. The demand of smart antennas and intelligent sensors significantly increases when dealing with multiuser communication system that needs to be adaptive, especially in unknown adverse environment [1–3]. The smart antennas based arrays are capable of steering the main beam in any desired direction while placing nulls in the unwanted directions. Intelligent sensor networks integration with smart antennas will provide algorithms and interesting application to collect various data of environment to make intelligent decisions [4, 5]. The aim of this special issue is to provide an inclusive vision on the current research in the area of intelligent sensors and smart antenna based systems for enabling various applications and technologies. We cordially invite some researchers to contribute papers that discuss the issues arising in intelligent sensors and smart antenna based system. Hence, this special issue offers the state-of-the-art research in this field

Fuzzy logic controller for half car active suspension system

This work presents the MATLAB/Simulink simulation results of half car active suspension system controlled by the fuzzy logic controller. The half car model consists of one front and rear wheel. Firstly, a mathematical model of the suspension system is developed. Based on the developed mathematical model, the fuzzy logic controller for the system is designed. The input to the controller is the vertical displacement and velocity of the front body of the vehicle. The membership function of these two variables is adjusted accordingly so that the output, i.e., the car body acceleration, the deflection of the wheels and other output are better than that of the passive suspension system. The results clearly show that all of the active suspension system output has improved when compared to that of the passive system

Electrical characteristics of doped ZnOCu2O heterojunction diode by sputtering method

Heterojunction thin films made from the combination of oxide semiconductor have attracted much attention due to its wide range of functional properties and plenty of potential application in optical and electronic devices. Zinc oxide (ZnO) semiconductor gains interest due to its versatile characteristics with wide direct band gap of 3.37 eV with added advantages to be used as in optoelectronics devices. In this paper, the electrical performances of heterojunction n-type ZnO (n-ZnO) and p-type cuprous oxide (p-Cu2O) diodes will be compared with Al doped ZnO/Cu2O and Ga doped ZnO/Cu2O diodes. Heterojunction nZnO/p-Cu2O diodes were fabricated by RF sputtering method. Pure ZnO ceramic target with 99.99% purity used as material target for ZnO thin films. A mixture of 3 wt% Al2O3 with 97 wt% ZnO and a mixture of 3 wt% Ga2O3 with 97 wt% ZnO used as target material for doped ZnO thin films. Several measurements such as resistivity, I-V curve, threshold voltage, series resistance and diode ideality factor were investigated. The overall results suggest that the doped heterojunction n-ZnO/p-Cu2O diodes perform far better as compared to pure n-ZnO/pCu2O

Electrical-field activated sintering and forming of micro-components

As the demand for miniature products has increased significantly, so also has the need for these products to be produced in a rapid, flexible and cost efficient manner. The application of electroplasticity shows significant potential to produce the components by using powder materials. Nevertheless, previous research has shown that there are still significant challenges to be met in order to achieve increased relative densification of product samples and simplification of the processes. The process concept in this study comprises the combination of electrical-field activated sintering and forming processes. Therefore, the aims of the research were to develop the process concept for the manufacture of micro-components and to design the die sets along with other tooling for machine setup to enable the forming of micro-components from powder materials. A comprehensive literature review on micro-manufacturing, size effects, powder metallurgy and the electroplasticity process has been conducted. The development of the die sets for the process has been described, followed by a series of experiments. The FE thermal-electrical analysis was also carried out to study the heating flows of the die sets development during the process. In this research, titanium (Ti) and titanium tin alloy (90Ti10Sn) have been selected for the main powder materials tested for both vacuum and open-air process environment by using a Gleeble® 3800 testing system and Projection Welding machine respectively. Meanwhile, for the additional experiment, copper (Cu) has been selected to be tested in the open-air process environment by using a Projection Welding machine with die sets prepared by the Micro-FAST project. Based on the data collected, this efficient process has the potential to produce components with a high relative density of around 98%. Changes of the particles concerning deformation and breaking are crucial in the course of achieving the densification which differs from a conventional sintering process

Mangrove species' association and distribution patterns in Tumpat, Kelantan Delta, east coast of peninsular Malaysia

We studied mangrove vegetation at Tumpat to estimate different tree structural parameters (e.g., stem density and basal area) at selected sites (PCQ-Method). There were 5 dominant taxa in the vegetation, i.e., Sonneratia caseolaris, Nypa fruticans, Avicennia alba, Rhizophora mucronata, and Bruguiera gymnorrhiza in order of importance. Total tree density varied between 79 and 132 stems 0.1ha-1, and basal area from 0.14 to 4.9m2 0.1ha-1. Based on species composition and stem density, the mangrove sites could be separated into two groups (Bray-Curtis similarity: 60%). While Group-1 (sites G9, J5, K4, N6 and O4), dominated by S. caseolaris and N. fruticans, was distributed throughout the forest, Group-2 (sites C6 and G6), represented largely by A. alba, is present close to the bay-mangrove boundary. Elevation measurements indicate that Group-1 species occupied lowlying to elevated grounds (0.87-2.23m above the mean sea level) with a (mean) salinity between 0.38 and 14.6psu, whereas Group-2 occurred preferentially at low to medium elevations (0.86-1.29m) and high salinity (14.6psu). Discrete mangrove associations (=groupings) were discerned, wherein the distribution of species is governed by factors such as proximity of land or sea, freshwater input and elevation

Photovoltaic technologies photo-thermal challenges: Thin active layer solar cells significance

Massive energy demand and source of energy usages is the key root of global emission and climate change. Solar photovoltaic (PV) is low carbon energy technology currently 3.2% share of global electricity supply. The rapid progress of solar PV is vastly related to increase energy efficiency and lessening of active materials usage. This paper solar PV present significance and most prospective PV materials technical challenges are reviewed for its future advancement. Among the challenges solar energy absorption-related dynamic photo-thermal effect on cells or modules is vital. Transparent passivation contact materials with lower temperature coefficient (TC) and thin active layer resulted in lowering both dynamic photo-thermal outcome and optical to electrical energy gap. Thin active layer minor bulk recombination and sub-band parasitic absorption lessening purpose transparent conductive materials (TCM) based proper band barrier heterointerface is impending. It can optimize desired band absorption and photo-coupling with selective carrier induces greater efficiency. Earlier research though explains it on carrier selectivity prejudice, but how it can lessen the near infrared band optical and associated thermal influence is essential to illustrated. Passivation and TC interrelations hence, field related drift is control over diffusion process loss in advanced bifacial and thin active layer PV technology. Loss lessening pathways thin wafer-based Si, thin film CdTe, organic and perovskite photo coupling with advanced TCM, thus, Si/CdTe and Si/perovskite tandem cells along with OSC building integrated transparent photovoltaic technologies advancement pathways are reported

Fuzzy Logic Controller for Half Car Active Suspension System

This work presents the MATLAB/Simulink simulation results of half car active suspension system controlled by the fuzzy logic controller. The half car model consists of one front and rear wheel. Firstly, a mathematical model of the suspension system is developed. Based on the developed mathematical model, the fuzzy logic controller for the system is designed. The input to the controller is the vertical displacement and velocity of the front body of the vehicle. The membership function of these two variables is adjusted accordingly so that the output, i.e., the car body acceleration, the deflection of the wheels and other output are better than that of the passive suspension system. The results clearly show that all of the active suspension system output has improved when compared to that of the passive system

Numerical study of nSi and nSiGe solar cells: Emerging microstructure nSiGe cell achieved the highest 8.55% efficiency

This paper reports about the comparative study of nSi and nSiGe microstructure materials opto-electrical energy conversion prospect. The significance of nSiGe thin active laye in organic-inorganic heterojunction (HJ) solar cell efficiency progression is illustrated. Transparent and carrier selective top contact purposes p-type un-doped organic materials are promising for low processing cost n-Si HJ solar cell. Near infrared band absorption enrichment by Ge inclusion in n-Si thin active layer is a new design approach. p-PTAA/n-Si PV device modelling and it electrical properties are investigated by using SCAPS simulator. Thin Si active layer solar cell is commercially important. However, thin layer absorption related technological shortcoming overcoming approaches 10% Ge content impact is studied in this work. Moreover, SiO2 nanomaterial passivated p-PTAA/SiO2/ n-SiGe and p-PTAA/SiO2/n-Si models active layer thickness and operating temperature effects have also been studied. The current-voltage (J-V) characteristics analysis is realized that nSiGe cell is potential for the progression of current density and efficiency. SiO2 nanomaterial passivated 3 μm SiGe microstructure cell is realized promising to increase 48.1 mA/cm2 of current density. The highest 8.55% efficiency is achieved for 2 nm SiO2 passivation and 20 nm of PTAA emitter

Optoelectronic properties comparison of 10 and 20 multi quantum wells Ga0.952In0.048N0.016As0.984/GaAs p-i-n photodetector for 1.0 µm wavelength

This study proves the addition of quantum wells to the intrinsic regions of p-i-n GaInNAs/GaAs has improved the performance of optoelectronic devices. The optoelectronic properties that contribute to the device's dark current and photocurrent need to be well understood to develop photo-response at longer wavelengths. This study reports an optoelectronic properties comparison of different quantum well number for Ga0.952In0.048N0.016As0.984/GaAs-based dilute nitride multi-quantum wells (MQWs) p-i-n photodetector devices. From photoluminescence (PL) analysis, 20 MQWs shows a higher PL peak than 10 MQWs. The maximum quantum efficiency (QE) is found to be 80.3% for 20 MQWs and 46% for 10 MQWs, where 20 MQWs being the highest QE value ever reported for GaInNAs-based MQWs photodetector. Current versus voltage (I–V) measurement shows that 20 MQWs produces lower dark current than 10 MQWs. Besides, 20 QWs sample produces a higher current density (−12.43 μAcm−2) than 10 MQWs (−7.52 μAcm−2) under illumination. Impedance spectroscopy analysis shows that a lower dark current of 20 MQWs is due to a high intrinsic resistivity and low dielectric loss peak compared to 10 MQWs. SimWindows simulation shows good correlation with responsivity analysis and impedance analysis where at −5 V, 20 MQWs produces higher responsivity (0.65AW-1) due to wider depletion region (deduce from conduction band profile) and lower intrinsic capacitance and dielectric loss (deduces from impedance analysis) than 10 MQWs (0.37AW-1). At room temperature, the detectivity (D*) of the 20 MQWs photodetector (7.12 × 1010 cmHz0.5W−1) is higher than 10 MQWS photodetector (4.89 × 1010 cmHz0.5W−1). Finally, the 20 MQWs's (4.02 × 10−11 WHz−0.5) has produces lower noise-equivalent power (NEP) than 10 MQWs (5.85 × 10−11 WHz−0.5). This study has successfully presenting an understanding of optoelectronic properties and simultaneously producing a sensitive photodetector with high quality, low-noise which is comparable with ∼1010 cmHz0.5W−1 of commercial III-V alloy based near-infrared GaAs-based photodetectors