Performance Evaluation of RF Energy Harvesting Circuit with DRA and Planar Antennas

Wireless Personal Communications - In this paper, we have proposed a lightweight blockchain based model to provide distributed authentication and anonymous authorization in IoD. We have proposed...     

A multilevel hybrid anomaly detection scheme for industrial wireless sensor networks

Real-time sensing plays an important role in ensuring the reliability of industrial wireless sensor networks (IWSNs). Sensor nodes in IWSNs have inherent limitations that give rise to different anomalies in the network. These anomalies can lead to disastrous and harmful situations or even serious system failures. This article presents a formulation to the design of an anomaly detection scheme for detecting the anomalous node along with the type of anomaly. The proposed scheme is divided into two major parts. First, spatiotemporal correlation within a cluster is obtained for the normal and anomalous behavior of sensor nodes. Second, the multilevel hybrid classifier is used by combining the sequential minimal optimization support vector machine (SMO-SVM) as a binary classifier with optimally pruned extreme learning machine (OP-ELM) as a multiclass classifier for detection of an anomalous node and type of anomalies, respectively. Mahalanobis distance-based lightweight K-Medoid clustering is used to build a new set of training datasets that represents the original training dataset, by significantly reducing the training time of a multilevel hybrid classifier. Results are analyzed using standard WSN datasets. The proposed model shows high accuracy, i.e., 94.79% and detection rate, i.e., 94.6% with a reduced false positive rate as compared to existing hybrid methods.     

FGMOS transistor based low voltage and low power fully programmable Gaussian function generator

In this paper floating gate MOS (FGMOS) transistor based fully programmable Gaussian function generator (GFG) is presented. The circuit combines the exponential characteristics of MOS transistor in weak inversion, tunable property of FGMOS transistor, and its square law characteristic in strong inversion region to implement the GFG. FGMOS based squarer is the core sub circuit of GFG that helps to implement full Gaussian function for positive as well as negative half of the input voltage. FGMOS implementation of the circuit provides low voltage operation, low power consumption, reduces the circuit complexity and increases the tunability of the circuit. The performance of circuit is verified at 0.75 V in TSMC 0.18 μm CMOS, BSIM3 and level 49 technology by using Cadence Spectre simulator. To ensure robustness of the proposed GFG, simulation results for various process corner variations have also been included.     

Tensile Behavior of Single-Crystal Tin Whiskers

The growth of metallic (predominantly Sn) whiskers from pure metallic platings has been studied for over 50 years. While the phenomenon of Sn whiskering has been studied for decades, very little is known about the mechanical properties of these materials. This can be attributed to the difficulty in handling, gripping, and testing such fine-diameter and high-aspect-ratio whiskers. We report on the stress–strain behavior of Sn whiskers inside a dual-beam focused ion beam (FIB) with a scanning electron microscope (SEM). Lift-out of the whiskers was conducted in situ in the FIB, and the whiskers were tested using a microelectromechanical system tensile testing stage. Using this technique, the whiskers had minimum exposure to ambient air and were not handled by hand. SEM images after fracture enabled reliable calculation of the whisker cross-sectional area. Tests on two different whiskers revealed relatively high tensile strengths of 720 MPa and 880 MPa, respectively, and a limited strain to failure of ～2% to 3%. For both whiskers, the Young’s modulus was between 42 GPa and 45 GPa. It is interesting to note that the whiskers were quite strong and had limited ductility. These findings are intriguing and provide a basis for further work to understand the effect of Sn whisker mechanical properties on short circuits in electronics.     

Fast Ion Transport in Li-Rich Alloy Anode for High-Energy-Density All Solid-State Lithium Metal Batteries

All-solid-state Li batteries (ASSLBs) with solid-polymer electrolytes are considered promising battery systems to achieve improved safety and high energy density. However, Li dendrite formation at the Li anode under high charging current density/capacity has limited their development. To tackle the issue, Li-metal alloying has been proposed as an alternative strategy to suppress Li dendrite growth in ASSLBs. One drawback of alloying is the relatively lower operating cell voltages, which will inevitably lower energy density compared to cells with pure Li anode. Herein, a Li-rich Li₁₃In₃ alloy electrode (LiRLIA) is proposed, where the Li₁₃In₃ alloy scaffold guides Li nucleation and hinders Li dendrite formation. Meanwhile, the free Li can recover Li's potential and facilitate fast charge transfer kinetics to realize high-energy-density ASSLBs. Benefitting from the stronger adsorption energy and lower diffusion energy barrier of Li on a Li₁₃In₃ substrate, Li prefers to deposit in the 3D Li₁₃In₃ scaffold selectively. Therefore, the Li–Li symmetric cell constructed with LiRLIA can operate at a high current density/capacity of 5 mA cm⁻²/5 mAh cm⁻² for almost 1000 h.     

A theoretical study of the performance of sub-micron MOSFET devices in the presence of edge potential

In the present communication we have presented a detailed theoretical analysis of the performance of the sub-micron device in the presence of the discontinuity at the Si–SiO₂ interface. It is assumed that due to interface discontinuity a potential develops at the edges (Source/Drain) in addition to the built-in-potential. This potential, called Edge Potential, measures directly the extent of the interface roughness. The effect of this potential is more critical in the case of short channel device where drain and source are in close proximity. Our analysis shows that the discontinuity is dominant at the edges but not in the channel. Drive current as well as saturation transconductance decreases in the presence of edge potential. These results suggest that the performance of the device degrades due to the interface roughness. Effect of interface roughness near the edges can be reduced at high gate voltage but it will result more interface roughness scattering.     

Combating/eliminating dispersion-induced fading using suppressed carrier link for OFDM signal

We investigate the performance of 20-GHz radio over fibre (RoF) system having orthogonal frequency division multiplexed (OFDM) as radio signal using two modulation techniques – balanced detection for intensity modulation direct detection (IMDD) and coherent heterodyne detection suppressed carrier (SC) modulation. Dispersion-induced power fading is seen in conventional IMDD links due to the dependence of dispersion over frequency-dependent refractive index of the fibre. SC link is seen to compensate the power fading by terminating the direct current and even-order harmonics with the suppression of carrier along with balanced detection.     

Programmable memory cell using quantum confined Stark effect in multi-quantum well heterojunction bipolar transistor

A three terminal bistable programmable memory cell which can be read either optically or electrically is proposed and demonstrated. The device is based on using Stark effect of the excitonic transitions in a multi-quantum well base region of a heterojunction bipolar transistor. The single device can be flipped (and held) from low transmittance (high voltage) to high transmittance (low voltage) state and vice versa by a varying base current signal.<>     

Study of meander line delay in circuit boards

A moment technique is used to determine the propagation delay in meander (serpentine) delay lines located in printed circuit boards of computer systems. The full three-dimensional effects of the meander structure including signal line thickness, right-angle bends, and skin-effect are included. A set of delay lines having different pitches are considered, and results are calculated and compared to those from two-dimensional simulations, other commercial codes, analytic formulas in the literature, and experimental measurements. Based on the consistency of the results and sensitivity analyses involving numerical gridding and frequency content, the delays calculated for meander lines situated in a homogeneous medium are accurate to better than a few tenths of a percent