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A wideband and circularly polarized hybrid ring CDRA is proposed for the applications of C, X and Ku-band. A small size two-headed drum-shaped aperture (Damaru shaped) inclined at 45° and microstrip line feed generates two orthogonal modes (HEMx11δ and HEMy11δ). The suggested ring CDRA of wideband characteristic is resonating between frequency band 6.96 to 14.12 GHz with 67.93% (7160 MHz) impedance bandwidth. oreover, dual-band circular polarization characteristics are also achieved from 8.22 to 9.53 GHz and 12.29 to 13.71 GHz with 3-dB axial ratio bandwidth (ARBW) of 14.76% (1310 MHz) and 10.92% (1420 MHz) respectively. The impact of various parameters of ring CDRA and aperture orientation on the functionality of the suggested antenna is also studied. The proposed radiator is fabricated on a 40 × 40 mm2 (0.93 × 0.93λ02 at lower cut-off frequency 6.96 GHz) FR-4 substrate of 1.6 mm thickness. Moreover, peak gain of 7.43 dB at frequency 12.66 GHz and radiation efficiency greater than 80% in the whole operating frequency is also achieved. [ABSTRACT FROM AUTHOR]

Generally, seismic data have discontinuity or planar fracture anomalies in the volume of rocks, commonly known as seismic faults. A large number of methods exist to interpret seismic faults, nevertheless automating the process prevails to be a practical challenge. We propose a graph representation-based approach for interpreting faults in seismic data using the graph convolutional network (GCN). We extract 2D patches of data centered around seismic data points from the 3D seismic volumes for training. Then we represent these patches in the graph domain using the k-nearest neighbor graphs followed by the application of GCN. After training the patches in the networks, we classify the patches to identify the faults. We consider both synthetic and real data for training and testing. The seismic amplitude values, the seismic attribute values, and the successive difference values are used in the networks. We compare our implementation with the state-of-the-art method, the convolutional neural networks (CNN). The results show good accuracy when applied to both synthetic and real data. Additionally, the GCN method is more time efficient than that of CNN. We process the 3D seismic section by parallel processing the 2D patches. [ABSTRACT FROM AUTHOR]

This article presents a dual-band circularly polarized hybrid ring CDRA (Cylindrical dielectric resonator antenna) for wireless applications in C and X-band. A circular ring inclusive of a slotted cross-shaped microstrip feed line is used to excite the ring CDRA and generation of HEM11δ and TEM01δ modes. Multiple inverted Z-shaped apertures and circular ring along with a slotted cross-shaped microstrip feed line are responsible for the generated circular polarization wave between 3.92 and 4.08 GHz in lower band and 8.85 to 9.61 GHz in upper band with 4% (160 MHz) and 8.23% (760 MHz) axial ratio bandwidth (ARBW) respectively. The proposed antenna also offers impedance bandwidth of 20.58% (780 MHz) between 3.40 and 4.18 GHz in lower band while 29.31% (2490 MHz) between 7.25 and 9.74 GHz in upper band resonating at 3.73 and 7.79 GHz with − 26.4 and − 35.61 dB return loss respectively. The proposed ring CDRA shows stable gain of peak value 5.8 dB (simulated) and 5.8 dB (measured) in lower band while 7.7 dB (simulated) and 8.2 dB (measured) in upper band. [ABSTRACT FROM AUTHOR]

Janus materials exhibit novel and interesting characteristics with a diversified potential applications. These owe to their unique property of structural asymmetry, which break the out-of-plane reflection and lead to a spontaneous electric field. This manuscript investigates a group-IV dichalcogenide Janus monolayer G e 2 S e T e in detail for its thermoelectric performance. The density functional theory has been used as a toolkit for this investigation. The absence of imaginary frequency in the phonon spectra confirms the dynamic stability of the investigated structure. Moreover, to confirm the thermal stability of the system, we have performed the AIMD (Ab-Initio Molecular Dynamics) calculation using the Car-Parllinno algorithm which assures that the structure, is thermally stable. The elastic constants have also been calculated to keep track of mechanical stability. To achieve high accuracy and precise calculations, we have used Hybrid functional (HSE06) to model the exchange-correlation, and deformation potential approach to estimate the scattering time (τ ). All the thermoelectric transport parameters were calculated by solving the Boltzmann transport equation with a constant relaxation time approximation. The research findings reveal that the investigated monolayer exhibit an ultra-low lattice thermal conductivity of the order of 0.13 W m - 1 K - 1 at room temperature and 0.04 W m - 1 K - 1 at 900 K with outstanding thermoelectric figure of merit (nearly 2.12 at room temperature and 3.52 at 550 K). The superlative thermoelectric performance of Janus monolayer G e 2 S e T e makes it suitable for an efficient thermoelectric device at mid-temperature regimes. [ABSTRACT FROM AUTHOR]

This article presents a dual-band dual-polarized, slotted cylindrical dielectric resonator antenna (CDRA) for wireless applications. Multiple inverted pentagons with slotted aperture are used to radiate hybrid mode HEM11δ. The suggested radiator has two operating frequency bands: lower frequency band is from 3.75 to 3.96 GHz with 5.44% (210 MHz) fractional bandwidth resonating at 3.87 GHz while upper frequency band is from 6.58 to 8.4 GHz with 24.29% (1820 MHz) fractional bandwidth resonating at 6.63 GHz. The lower resonating band is generated because of multiple slots while upper resonating band is due to the combination of CDRA and multiple slots. The lower band is linearly polarized whereas the upper band is dual-polarized (linear/circular). Circular polarization (CP) characteristic is achieved at the upper frequency band by combining the effect of moon-type microstrip line and multiple slots. Axial ratio bandwidth (3-dB) is obtained about 7.06% (550 MHz) between 7.52 and 8.07 GHz with 0.62 dB minimum AR value at frequency 8.01 GHz. This radiator can be used in partially S and C-band applications. [ABSTRACT FROM AUTHOR]

The discovery of 2-D Janus materials has accelerated the research and development of novel nanodevices for numerous applications. Owing to its unique properties of structural asymmetry, the 2D Janus monolayers are extensively expedited for an optoelectronic, piezoelectric, thermoelectric behavior of the materials. Motivated with this, we have explored the thermoelectric behavior of Janus MoSeTe monolayer using an ab-initio technique. Moreover, we have calculated the electronic, vibrational, and transport parameters using density-functional theory, density functional perturbation theory and Boltzmann transport equations, respectively. To get an accurate calculation, the precise scattering time has been estimated at various temperatures using the deformation potential theory, instead of using constant relaxation time. In addition to it, the lattice thermal conductivity which is a crucial parameter to explore the thermoelectric behavior is also calculated. Interestingly, we have observed an ultra-low lattice thermal conductivity (0.095 Wm - 1 K - 1 at room temperature to 0.02 Wm - 1 K - 1 at 1200 K). Also, the sufficiently high thermoelectric figure of merit (around 3) makes this material promising for thermoelectric applications under high-temperature regimes. [ABSTRACT FROM AUTHOR]

BaMnxTi1-xO3 thin film on a silicon substrate has been prepared through the sol–gel spin coating process. The ferroelectric BaMnxTi1-xO3 film shows the predominant perovskite ABO3 structure for x = 0.2 and 0.3 for the annealing temperature of 650 °C under nitrogen ambient. The metal contact on top and silicon substrate at the bottom of the film forms a Metal-Ferroelectric-Semiconductor capacitor structure. In BaMnxTi1-xO3, the deposited film changes its structural and electrical properties as the concentration value of 'x' is changed. The crystal structure of the deposited film has been analysed by XRD. FESEM, EDS and XPS characterization of the film were carried out to discuss the change in the film structure with the change in the value of 'x'. The Capacitor vs. Voltage (C–V), Current vs. Voltage (I–V), Charge vs. Voltage (Q–V), Endurance, PUND (Positive Up Negative Down) and dielectric study of the films are discussed. Memory window of 8.6 V and leakage current of few nA are obtained. The deposited ferroelectric film shows an endurance of ~ 1011 iteration cycle for the PUND pulse. The optimized doping molar concentration 'x' in BaMnxTi1-xO3 shows favourable results for ferroelectric non-volatile memory application with a low cost fabrication method. [ABSTRACT FROM AUTHOR]

Thin film of Barium–Strontium–Titanate (BaxSr1−xTiO3) has been fabricated through sol–gel spin-coating process with optimized value of 'x' for non-volatile memory application. The Metal–Ferroelectric–Semiconductor (MFS) thin-film structures have been prepared using Barium–Strontium–Titanate (BST) with various Barium/Strontium (Ba/Sr) molar concentrations. The BST films prepared through sol–gel process are annealed at 650 °C in nitrogen ambient. The structural and electrical characterizations have been carried out for each of the samples. From the characterization, it is realized that the BST films are having significant changes in its electrical and structural properties on changing the molar concentration of Barium and Strontium. It has been observed that the crystallinity of the film, refractive index, leakage current (I−V), capacitance vs. voltage (C−V) relation, and the charge vs. voltage (Q–V) relation vary with the varying values of 'x' in BaxSr1−xTiO3 and have been presented graphically. The maximum memory window up to 9 V with average leakage current within the range of 100 nA and minimum of 10 pA for 0 V has been achieved for the sweep voltage of + 15 V to -15 V. Memory window and leakage current are optimized and discussed. Endurance testing through PUND (positive up negative down) pulse shows that the samples can sustain up to 1010 iteration pulses. These findings indicate the use of optimized BST film for ferroelectric non-volatile memory applications through sol–gel process. [ABSTRACT FROM AUTHOR]

In this communication, the structural and electrical properties of metal–ferroelectric–insulator–silicon (MFIS) capacitor structure have been reported for non-volatile memory applications. Sol–gel with spin coating and rf sputtering process have been used for depositing BiFeO3 (BFO) and ZrO2 films, respectively. It has been observed that BFO film shows pure ferroelectric phase, uniform grain size and maximum refractive index at annealing temperature of 500 °C. Thermo-gravimetric analyzer and differential scanning calorimetry analysis indicate good agreement with X-ray diffraction of BFO film. In ZrO2 thin film, it has been observed that ZrO2 is in amorphous state at all annealing temperatures and the maximum refractive index has been found at annealing temperature of 400 °C. Al/ZrO2/n-Si (MIS), Al/BiFeO3/n-Si (MFS) and Al/BiFeO3/ZrO2/n-Si (MFIS) structures have been fabricated to investigate the electrical characteristics. The memory window has been observed by capacitance–voltage (C–V) characteristics and it improves from 1.9 V in MFS structure to 5.4 V in MFIS structure with 8 nm dielectric layer. Leakage current density has been observed by current density–gate voltage (J–V) characteristics and it is order of 10−5 A/cm2 in MF150 nmI8 nmS structure. No charge value degrades up to 1012 iteration cycles in MF150 nmI8 nmS structure. [ABSTRACT FROM AUTHOR]

A metal–ferroelectric–insulator–semiconductor (MFIS) structure was fabricated with lanthanum (La)-doped BiFeO3 as ferroelectric and ZrO2 as the high-k insulator layer. The BiFeO3 film with 5 M doped La was prepared with sol–gel and ZrO2 film was physically deposited with rf sputtering. Films structural characteristics were obtained using X-ray diffraction and scanning electron microscopy (SEM). The ferroelectric film shows the perovskite structure with orientation (110)/(104) when annealed in the range from 400 to 700 °C. The dielectric film shows an amorphous structure for the same range of annealing temperature. Electrical and ferroelectric properties were obtained by fabricating and characterizing metal/ferroelectric/silicon (MFS), metal/ferroelectric/metal (MFM), metal/insulator/silicon (MIS), metal/ferroelectric/insulator/metal (MFIM) and metal/ferroelectric/insulator/silicon (MFIS) capacitor structures with ferroelectric film of 200 nm thickness and dielectric film of various thicknesses. MFS structure shows a maximum memory window of 3.5 V and leakage current density of 1.4 × 10–8 A/cm2 with ferroelectric film annealed at 500 °C. The memory window was further improved to 6.62 V and leakage current to the order 10–10 A/cm2 with the introduction of 9 nm insulator layer between ferroelectric and silicon. The same device shows an excellent endurance property tested for 1012 cycles and data retention tested for 5.56 h. The device shows a breakdown of 43 V, which is 9 V higher than the MFS structure. To the best of author's knowledge, this is the first report to integrate La-doped BiFeO3 on ZrO2 (high-k) dielectric for non-volatile memory applications. [ABSTRACT FROM AUTHOR]

In the present work, a metal-ferroelectric-semiconductor (MFS) structure for non-volatile memory application using barium titanate (BaTiO3) thin film is proposed. Sol–gel method is used to prepare the material, while deposition is done through spin-coating. A thin layer of BaTiO3 (BTO) film on a silicon substrate with MFS structure is fabricated followed by N2 dominant gas annealing. The electrical properties and the non-volatile memory operations characteristics of prepared MFS structure with BTO as the ferroelectric thin film are observed and discussed. Two different solvents are used to prepare the sol–gel of BTO material and prepared films are compared on the basis of morphological and electrical properties. It is found that the film prepared by 2-methoxyethol is better than the film prepared by ethanol. The device's performance is evaluated by changing the annealing temperature and variable sweep voltages. Memory window and leakage current improve at higher annealing temperature with saturation at 650 °C. A maximum of 6 V memory window is achieved for 650 °C annealed device. Saturation in memory window is also observed with respect to the voltage sweep up to − 6 V to + 6 V with a considerable remnant polarization value. Endurance property for the MFS structure shows promising result for the iteration cycle of 1013 using positive up negative down pulse testing. To the best of author's knowledge, this is the first report on BTO based MFS structure for memory application prepared through sol–gel process. [ABSTRACT FROM AUTHOR]