Rectangular Core Research Articles

Correlation of Core Thickness and Core Doping with Gate & Spacer Dielectric in Rectangular Core Shell Double Gate Junctionless Transistor

The impression of gate dielectric and spacer dielectric on the performance of rectangular core shell double gate junctionless transistor (RCS-DGJLT) using extensive simulations is studied. The RCS-DGJLT brings captivating response in terms of the performance of the device. The effect of gate dielectric and spacer dielectric is studied for the first time in RCS-DGJLT. The performance of the device gets improve on increasing the dielectric constant till core thickness (t core) = 3 nm for shell thickness (t shell) = 4 nm. However, beyond core thickness 3 nm, the performance degrades much for high k dielectric. Further, the performance is enhanced for t core > 3 nm and higher k dielectric on reducing the core doping. The device performance is also studied by incorporating the spacers. It has been shown that the device performance is best at t core = 4 nm with low k gate dielectric however, the device performance degrades when high k spacer dielectric is used on the same device which is an interesting and different outcome as compared to conventional DGJLT. The ON current and ON/OFF current ratio are improved by ∼3 orders of magnitude using highly doped source/drain region(HD-S/D) with high k spacers. The results show that the core is the integral part of the device, any engineering like spacers, gate dielectrics applied to RCS-DGJLT requires the optimization of the core carefully for better device performance.

Design and Characterization of Package-Embedded Solenoidal Magnetic Core Inductors for High-Frequency and High-Efficiency SIP Integrated Voltage Regulators

In this article, the design and characterization of package-embedded solenoid inductors for a high-efficiency, four-phase system-in-package (SIP) buck-type integrated voltage regulator (IVR) switching at 100 MHz is discussed. The IVR enables three conversion ratios (5, 3, and 1.7–1 V) with a minimum inductance of 25 nH/phase and a load current of 10 A (2.5 A/phase). Two inductor designs (one with a rectangular core made of an epoxy dielectric/NiZn ferrite composite magnetic material/epoxy dielectric stack and one with an elliptical core of NiZn ferrite composite magnetic material only) were optimized and compared based on the highest achievable IVR efficiency. At high-load conditions (>5 A), the elliptical core inductor showed higher efficiency than the rectangular core inductor over the frequency range investigated (10–100 MHz). The elliptical core inductors were fabricated using a novel fabrication process combining core printing, noncontact photolithography, and copper electroplating. Two simple deembedding techniques which use a single thru structure and its equivalent circuit model as well as a cascade-based two-port analysis were introduced for the characterizations of the fabricated inductors. The accuracy of these deemebedding techniques was assessed using commercial, fixed-air core inductors and standard THRU and thru–reflect–line (TRL) deembedding for comparison purpose. Less than 5% difference was observed between the TRL and the introduced deembedding techniques for the inductance and ac resistance for both the fixed air core and package-embedded magnetic core inductors. The extracted electrical parameters of the fabricated inductors were compared with the modeling results and a good correlation was observed at 100 MHz.

Determination of corrugated core sandwich panels elastic constant based on three different experimental methods and effect of structural integrity on flexural properties

This study deals with the investigation of flexural stiffness and transverse shear rigidity in the direction of corrugation of the integrated and non-integrated corrugated core sandwich panels with the rectangular core. The non-integrated sandwich panels were reinforced with conventional 2-D fabrics in which resin provides the bond between core and skins. The integrated sandwich panels were reinforced with 3-D weft knitted fabrics in which bonding of the core wall to skins was carried out by combined efforts of knitted loop and resin. Using weft knitting technical capabilities, samples of the integrated and non-integrated structures were manufactured with the uppermost degree of resemblance in terms of geometry and mass. Flexural stiffness and transverse shear rigidity of the structures based on the known and unknown facing modulus of ASTM D7250 standard and Nordstrand–Carlsson methods were calculated. The estimated elastic constants based on unknown facing modulus and the Nordstrand–Carlsson methods were found to be highly compatible. However, the unknown facing modulus method is prone to disclose the statistical significant differences between the elastic constants of the structures with fewer tests. Regarding the unknown facing modulus method, it was found that the flexural stiffness and transverse shear rigidity of the non-integrated structure in the direction of corrugation were higher than those of the integrated structure. Results also indicated that the load-carrying capacity in the direction of corrugation was significantly higher in case of the non-integrated rectangular core structure compared with that of the integrated structure.

Performance Analysis for Tri-Gate Junction-Less FET by Employing Trioxide and Rectangular Core Shell (RCS) Architecture

With the advancement in technology scaling and featuring new device design is being explored to meet the demand for low power and high-speed circuit design. Tri-gate junction-less FET (TGJLFET) is taken as a reference model in this study. The structure of the reference model is modified to arrive at three different device structures; the first one with two dielectric materials for gate oxide, the second one with three dielectric materials, and the third with three dielectric materials with Rectangular Core–shell (RCS) Architecture having opposite doping at the center of the channel. The performance of these three new structures was evaluated and compared with one another and also with the reference model structure. Investigated performance parameters include leakage current, sub-threshold swing, Drain induced barrier lowering (DIBL), threshold voltage, transconductance (Gm), Output Conductance (Gd), Early Voltage (Ve), Intrinsic Gain (Av), the potential at core and surface fin of the Tri-gate device. The simulation results reveal that the device with gate trioxide with RCS Architecture shows good performance with respect to the above parameters when compared with the two new device structures and reference model. Further, an inverter is simulated using TGJLFET trioxide with RCS Architecture and its DC analysis and signal to noise margin were studied. For all the simulations 3D visual TCAD device simulator from Cogenda Pvt Ltd is used.

High efficiency active Q-switched laser operation with a large size rectangular core crystalline waveguide.

High efficient pulse output from a large size rectangular core crystalline waveguide actively Q-switched laser was achieved experimentally. A crystalline waveguide, with a rectangular core size of 320μm×400μm by 1.0at.% Yb:YAG (core), 600μm×600μm by 0.5at.% Er:YAG (cladding), and 7mm×7mm by 4.0at.% V:YAG (outside of the cladding) was designed and fabricated. Using a continuous diode laser as an end pump, an output pulse energy 1.75mJ@10kHz, pulse width 9.9ns (peak power 175kW), optical-optical efficiency 26%, with the beam quality of Mx2=1.15, My2=1.10, were obtained in the experiment. The design method that used to suppress amplified spontaneous emission (ASE) and parasitic oscillation by cutting off the reflection and transmission paths, can be applied for various kinds of crystalline waveguide Q-switched or mode-locked lasers.

Investigation of novel multi-layer sandwich panels under quasi-static indentation loading using experimental and numerical analyses

In this study, the effect of multi-layering in sandwich panel composite structures with different configurations of corrugated cores under the effect of quasi-static indentation loading is investigated experimentally and numerically. Composite plates and corrugated cores with equal weight fraction were manually made using ML506 epoxy resin with 15% hardener and the overall volume fraction of 45% for woven glass fibers. Experiments were performed using a cylindrical indenter with a diameter of 20 mm and a semi-spherical nose shape, and the behavior of the composite structure was evaluated in the case of energy absorption, contact force, and fracture mechanisms for different corrugated cores (rectangular, trapezoidal and triangular). Progressive damage analyses of the composite samples were investigated using well-known 3D failure criteria developed in ABAQUS software, and an acceptable agreement between the experimental and numerical results was observed. Experimental results show that multi-layering of composite sandwich panels not only increases the structural strength in quasi-static indentation process but also increases the energy absorption of specimens by increasing the peak load, instantaneous force, and dislocation displacement up to the complete penetration. By comparing different geometries of the corrugated cores in terms of maximum force, energy absorption, and specific energy, it was shown that the functionality of specimens with rectangular cores is the best. Among the most important damage mechanisms of the examined sandwich panel specimens (visual analysis) in the quasi-static indentation process, matrix cracking, fiber breakage, delamination, cell walls buckling and crushing, face sheets and core debonding, and specimens complete penetration are noticeable.

High-resolution wavemeter based on polarization modulation of fiber speckles

For speckle pattern-based wavemeters or spectrometers, the intermodal and the chromatic dispersion of the diffusion waveguide are key factors in determining the wavelength resolution. In this study, we propose a new mechanism to modulate the fiber speckles aside from the dispersion related effect. The polarization modulation is introduced in a rectangular core fiber (RCF) by using an in-line polarization rotator (IPR). The IPR can rotate the polarization angle at different wavelengths. Interestingly, it is observed that the modulated speckle patterns appear periodically similar, and they present more variations when compared to unmodulated ones. The theoretical simulation indicates that the polarization exerts an influence on the fiber speckles by modulating the mode coupling coefficients when light is coupled into the RCF. In the demonstration experiment, we first built a precise laser frequency tuning system based on an electro-optic modulator and a microwave source. By comparing the recorded speckles with and without polarization modulation, the former speckles have lower correlations, which are evaluated using the Arc Cosine Similarity algorithm. Reconstructing the spectrum of speckles, the smallest detectable wavelength that can be detected with polarization modulation is 0.2 fm. The experimental results prove that the polarization modulation is a convenient and effective method to enhance the speckle’s wavelength sensitivity. In addition, this study paves a new way to design high-resolution wavemeters with shorter, more compact optical waveguides.

Design and optimization of terahertz blood components sensor using photonic crystal fiber

The article presents a rectangular core photonic crystal fiber (RCPCF) structure to detect the major components of blood. We used Topas as bulk fiber material for its extraordinary properties in the terahertz (THz) frequency region and the investigation is accomplished from 0.8 THz to 1.8 THz. The RCPCF sensor provides enriched relative sensitivity (almost 94.38%, 93.72%, 92.94%, 92.14%, and 90.8% for red blood cells (RBCs), hemoglobin (HB), white blood cells (WBCs), plasma, and water respectively at 1.8 THz frequency) with negligible confinement loss (only 2.75 × 10−13 cm−1, 2.87 × 10−13 cm−1, 3.06 × 10−13 cm−1, 3.27 × 10−13 cm−1, and 3.48 × 10−13 cm−1 for RBCs, HB, WBCs, plasma, and water respectively at 1.8 THz frequency). Besides, the proposed sensor offers a large effective area (approximately 3.382 × 105 μm2, 3.436 × 105 μm2, 3.493 × 105 μm2, 3.551 × 105 μm2, and 3.613 × 105 μm2for RBCs, HB, WBCs, plasma, and water respectivelyat 1.8 THz frequency). Also, this RCPCF sensor structure can be fabricated by utilizing the current fabrication techniques.

Design and characterization of rectangular slotted porous core photonic crystal fiber for sensing CO2 gas

In this article, we propose a rectangular slotted porous core photonic crystal fiber (RSPC-PCF) for sensing the CO2 gas. The RSPC-PCF is made of purely silica material with rectangular air holes in core and circular air holes in cladding. The COMSOL Multi-physics software with version 4.5.150 is used as a design and simulation tools. The effects of tuning the geometrical parameters have been numerically analyzed by using full-vector finite element method (FEM). The numerical results show the maximum relative sensitivity of 24% and minimum confinement loss of 0.0012 dB/m at 4 μm the absorption wavelength of CO2 gas. In addition, numerical aperture (NA) is also explored to check the light acceptance of the sensor. Since our proposed design is very simple having better sensitivity, it will be a suitable candidate for sensing the CO2 gas in the earth's atmosphere effectively.

General Correlations for Laminar Flow Friction Loss and Heat Transfer in Plain Rectangular Plate-Fin Cores

Abstract New generalized correlations for predicting the average fanning friction factor f and average Nusselt number Nu for laminar flow in plain plate-fin compact cores of rectangular cross section are presented. These are based on extended experimental data, as well as three-dimensional computational simulations, obtained for a broad range of fin density and geometrical attributes. The results indicate that while the fully developed forced convection scales only with the interfin channel cross-sectional ratio α (fin spacing by fin height), the entrance region hydrodynamic and thermal performance is additionally a function of the fin-core length L, flow Reynolds number Re, and fluid Prandtl number Pr. The developing flow and convection is further shown to scale as: (fRe)∼(L/dhRe)1/2, and Nu ∼(L/dhRe)1/2Pr1/3ϕ(α), where f, Re, and Nu are all based on the hydraulic diameter dh of the interfin flow channel. Generalized correlations for both (fRe) and Nu are developed by the corresponding scaling of the forced convection behavior and asymptotic matching of the entrance or developing flow (short fin-core flow length) and the fully developed flow (large fin-core flow length) region performance. Finally, the predictions from these correlations are found to be within ±15% of all available experimental data for air, water, and glycol (0.71 ≤ Pr ≤ 10), and fin cores with 0 < α ≤ 1.

Study of analog performance of common source amplifier using rectangular core–shell based double gate junctionless transistor

A new state of the art double gate junctionless transistor (DGJLT) namely the rectangular core–shell DGJLT (RCS-DGJLT) based common source amplifier circuit is designed to investigate the performance. An RCS-DGJLT device is designed using a visual technology computer aided design tool and look up table-based Verilog-A model has been designed to carry out spice simulation of the circuit. Device simulation of RCS-DGJLT shows the extraordinary performance when compared to conventional DGJLT. The RCS-DGJLT exhibits an OFF current (Ioff ) ∼10−14 A, ON current (Ion ) ∼10−5 A, ON/OFF current ratio (Ion /Ioff ) ∼109, subthreshold slope ∼68.9 mV decade−1 and drain induced barrier lowering ∼52.6 mV V−1. Also, the AC response of RCS-DGJLT exhibits good performance like lower miller capacitances of order 10–16 F, maximum unity gain frequency of 138.8 GHz, transconductance generation efficiency of 40 V−1, and gain-bandwidth product of 25.4 GHz. The common source amplifier circuit using RCS-DGJLT provides the amplification up to 3.3 times which implies gain (Av ) to be 3.3. The low leakage power of 10.4 pW and average power of 31.2 µW of common source amplifier circuit based on RCS-DGJLT shows the greater potential of using the proposed device in analog applications. Also, the complete flow chart of the process used to design an analog circuit based on proposed RCS-DGJLT is discussed. The result shows the potential of using the RCS-DGJLT device in designing high-frequency applications.

Investigations on single-mode fibers with rectangular core geometry

In this paper, we present a theoretical and experimental analysis on the properties of rectangular core fibers. We investigate the single-mode regime and the bending properties with respect to the aspect ratio of the rectangular core. In comparison to a standard step-index single-mode fiber, we show that a passive single-mode rectangular core fiber with an aspect ratio of ten is able to transport two times more power without the occurrence of nonlinear effects. For actively doped fibers, the threshold of nonlinear effects can be raised by up to 15%. For experimental verification a rectangular core fiber with an aspect ratio of three is manufactured and analysed. Here, the results between the numerical simulation and the experimental analysis are in agreement.

Theoretical investigations into magnetorheological finishing of external cylindrical surfaces for improved performance

Fine finishing entails increased percentage contact area, less friction, and less wear. The magnetorheological finishing is a precision process to obtain the fine finishing on the workpiece surface for improved functional applications. So, the rotary rectangular core-based magnetorheological finishing process is utilized for the precise finishing of the cylindrical external surfaces. The rotary-rectangular shaped tool core tip surface provides the uniformly magnetic flux concentration that further benefit to offer the uniform fine finishing on the cylindrical work-part's external surface. In this work, a theoretical model is developed to predict the reduction in the surface asperities during the magnetorheological finishing of the external cylindrical surfaces. The rotational speed of the rectangular tool core on the rotating cylindrical work-part enhances the relative speed of active abrasives, which decreases the pitch, helix angle, and increases the helical path length. These results enhance the uniform precise finishing on the cylindrical work-parts and also enhances the process performance. For validation of the theoretical roughness model, the experiments have been performed on the cylindrical external surface of the H13 die steel workpiece. The percentage error between the experimentally obtained Ra value and theoretical Ra value is found to be −4.76% to 3.06%, which shows the good agreement between the theoretical model and experimental results. It also shows the practicality and accuracy of the present process while finishing the H13 die steel and it is useful for many industrial applications.

Doping engineering to enhance the performance of a rectangular core shell double gate junctionless field effect transistor

This paper describes different architectures of a rectangular core shell double gate junctionless field effect transistor (RCS-DGJLT). The device performance has been studied when the core has either the same or opposite type of doping to the shell. It is found that an RCS-DGJLT with an oppositely doped core without heavily doped source/drain (S/D) extension regions exhibits an OFF current of ~10−14A and an ON current of ~10−5A. In addition, an RCS-DGJLT with heavily doped S/D extension and different placements of dopant concentration in the shell and core region is explored, so that control of charge carriers in the device during the ON and OFF states can be achieved. Further, the ON current is enhanced by doping engineering in the shell and core region without significantly degrading the OFF current. The RCS-DGJLT with heavily doped S/D extension along with oppositely doped core exhibits an OFF current of ~10−12A and an ON current of ~10−4A. The performance parameters such as the OFF current, ON current, ON/OFF current ratio, subthreshold slope, threshold voltage and transconductance are calculated. The performance of the proposed RCS-DGJLT fused with doping engineering is compared with previously published results on a DGJLT integrated with technology boosters from the literature, and is found to have superior performance to its counterparts.

Tuned Sloshing Dampers With Large Rectangular Core Penetrations

Abstract Space restrictions at the top of tall buildings may necessitate using tuned sloshing dampers (TSD) tanks with large rectangular penetrations to accommodate the structural core of the tower. A finite element model is employed to predict the natural sloshing frequencies and mode shapes of liquid sloshing in a rectangular tank with a rectangular core. Equivalent mechanical properties are determined to predict the sloshing response. Frequency response predictions of wave heights, sloshing forces, and energy-dissipation per cycle agree with results from shake table testing conducted on a rectangular tank with a rectangular core. Energy dissipation due to flow around the core adds considerable damping to the liquid and is proportional to the response velocity-squared. Nonlinear coupling among sloshing modes results in multiple peaks in the frequency response plots near the fundamental resonant frequency. An interior core with a broad dimension in one direction substantially reduces the fundamental sloshing frequency and equivalent mechanical mass in the perpendicular direction; however, the fundamental sloshing frequency and equivalent mechanical mass in the parallel direction are only influenced marginally. Large rectangular cores reduce the proportion of the total water mass that is effective in controlling tower motion. A TSD with a rectangular penetrating core may enable a TSD option to be considered for the control of a tall building in cases where a traditional rectangular TSD is infeasible.

Waveguide design optimization for compact silicon photonic ferroelectric phase shifters.

In this paper, a new, to the best of our knowledge, design for a ferroelectric BaTiO3 cladded silicon photonic phase shifter with very small switching length for compact photonic integrated circuits (PICs) is proposed. The proposed design is based on the choice of a waveguide core with suitably slanted sidewalls in order to favor the desired polarization of ferroelectric cladding and to make guided modes spread toward the ferroelectric cladding with the consequence of further reduction in switching length compared to the conventional (rectangular core) structure. The proposed design also gives the additional benefit of having the identical switching length for both TE and TM modes with the same configuration. These results offer a viable strategy to realize compact non-volatile phase shifters for reconfigurable and programmable PICs.

Fabrication and Characterization of a Flexible Fluxgate Sensor with Pad-Printed Solenoid Coils.

This paper presents the fabrication and characterization of a flexible, flat, miniaturized fluxgate sensor with a thin amorphous rectangular magnetic core fabricated by the pad/printing technique. Both the design and the various printing steps of the sensor are presented. The fluxgate sensor comprises of solenoid coils, and to the best of our knowledge, is the first to be printed with a conventional micro-printing technique. The magnetic core is a non-printed component, placed between the printed layers. The sensor’s linear measuring range is ±40 µT with 2% full-scale linearity error, at 100 kHz excitation frequency. The highest measured sensitivity reaches 14,620 V/T at 200 kHz, while the noise of the sensor was found to be 10 nT/ at 1 Hz.

On the multi-scale vibroacoustic behavior of multi-layer rectangular core topology systems

The present work deals with multi-layer rectangular core topology systems built up by stacking layers made of different rectangular core geometries. Multi-layer systems have been intensively studied in terms of mechanical performances whereas their vibroacoustic behavior, acoustic efficiency and design is however still an open issue. Several design parameters should be considered to fully understand the dynamic and acoustic behaviour of such structures. Therefore, this paper focuses on controlling the transition frequency and the Sound Transmission Loss (STL) by modifying geometrical parameters of the unit cell, while keeping the mass constant. Infinite panels and real wavenumbers will be considered in the study. The Wave Finite Element Method (WFEM) is used to obtain the targeted indicators. The proposed designs give the opportunity to shift the transition frequency and to control the flexural waves propagating in the structure. Besides, the STL is highly improved in the full frequency range of interest compared to a standard sandwich panel made of a single core.

Impact of core thickness and gate misalignment on rectangular core–shell based double gate junctionless field effect transistor

A rectangular core is inserted in double gate junctionless transistor (DGJLT) which separates the top shell and bottom shell in the device called as rectangular core–shell double gate junctionless transistor (RCS-DGJLT). The core doping and core thickness are optimized to improve the performance of RCS-DGJLT. The core thickness is optimized for different shell thicknesses in the device which has not been explored yet in the literature. An interesting observation is found that the core thickness should be equal to the shell thickness for smaller shell thicknesses, whereas the thicker core is required for larger shell thicknesses. RCS-DGJLT has shown remarkable improvement than DGJLT. Further, the effect of gate misalignment on either side (source/drain) of the channel in RCS-DGJLT and DGJLT is studied and compared on the basis of device performance. The study of gate misalignment becomes essential due to the complications on achieving perfectly aligned gates during the fabrication of double gate device. An RCS-DGJLT is found to have better tolerance to gate misalignment than DGJLT. The best parametric values like OFF current is ∼10–16A, ON current is ∼10–5A, subthreshold slope is nearly 66.2 mV/decade, ON/OFF current ratio is ∼1010, drain induced barrier lowering is ∼42.1 mV V−1 and threshold voltage ∼0.56 V at perfectly aligned gate condition is obtained on keeping core and shell thickness at 3 nm each. As per the analysis, the gate misalignment up to 20% on either side of the channel does not impact the performance parameters much and hence reduces the stress of meeting the requirement of perfect gate alignment.

Distribution of ligands in polynuclear palladium complexes: DFT study of isomerism of Pd4(L)4(RCO2)4 (L = CO, CH2, NO) complexes

Structural isomerism of the Pd4(L)4(RCO2)4 (L = CO, CH2, NO; R = CC13, CF3, CH3) complexes was studied in the framework of the density functional theory (DFT). Among the Pd4(CO)4(RCO2)4 and Pd4(CH2)4(RCO2)4 complexes the most stable were the isomers with alternate coordination of pairs of carbonyl and carboxylate ligands on the sides of a planar rectangular metal core. The isomers with the pairwise coordination of NO/RCO2 on one side of the metal core are the most stable between the Pd4(NO)4(RCO2)4 complexes. The features of mutual coordination of ligands in polynuclear complexes of palladium are clarified using the obtained results.