Journal of Computational Electronics最新文献

This article proposes a parameter extraction method suitable for Si substrate based GaN HEMT small signal equivalent circuit models. The proposed method is based on a swarm intelligence optimization algorithm, which improves efficiency and accuracy by introducing a slope penalty factor (SPF) method for the objective function, rather than simply minimizing the error between simulation and measurement. By using PSO, WOA, and PNC-WOA for validation, we have demonstrated the advantages of the SPF method in extracting small signal parameters using swarm intelligence optimization algorithms. It is suitable for complex small-signal models that can describe the GaN HEMT-on-Si substrates, even if working up to 40 GHz.

This paper presents two equivalent electrical circuit models of a dye-sensitized solar (DSS) module (150B-3 390). The module, which uses a third-generation solar cell, has several advantages over the earlier two generations. The equivalent model increases the research opportunities on solar cell technology development even without an existing solar plant. The paper highlights the development of an equivalent model of the module with the proposed method, as no such model is currently available to carry out further research with the module. The single-diode model (SDM) is a widely utilized simple approach that describes solar cell behavior very well. Model I in the paper is developed using only the SDM approach. It consists of a few unknown parameters estimated with the Gauss–Seidel method. The results from Model I show that the model requires certain improvements, due to the fundamental differences in the characteristic curves between conventional solar cells and DSS cells. The proposed model can more precisely describe the behavior of the module. Gauss–Seidel, curve fitting, and theoretical methods were used to develop the proposed model. It describes the irradiance effect of the module by introducing two newly developed parameters to Model I. The proposed model, with the theoretically modified characteristic equation of Model I, illustrates the temperature effect. The experimental work for the modeling is carried out on the DSS module inside a laboratory environment with standard test conditions. A Raspberry Pi 4 B with sensing devices is used to extract the measurable parameters from the module. Both models are based on an SDM design approach. Characteristic curves of the module from measured data validate the output characteristics of both models at various irradiance and temperature values. The results confirm the superiority of the proposed model over Model I.

The relaxation dynamics of photoexcited carriers of CdTe is vital toward its applications in high-performance optoelectrical devices. In this paper, the dependences of transient drift velocities of photoexcited electrons in bulk CdTe on photoexcitation conditions such as the pump intensity and photoexcitation wavelengths, temperature and externally applied electric field, are systematically investigated by the ensemble Monte Carlo method (EMC). The main scattering mechanisms including nonelastic deformation potential acoustic phonon, deformation potential optical phonon scattering, ionized impurity (II) scattering, and polar optical phonon scattering events, the effects of nonequilibrium phonons, and the Pauli exclusion principle are considered in EMC. The velocity overshoot phenomenon is only found to arise at a low temperature (100 K), with a longer photoexcitation wavelength (640 nm) and under a higher electric field (> 50 kV/cm). The effect of nonequilibrium phonons on electron drift velocity is found to be dependent on the photoexcited carrier density. Our findings may be useful for designing novel CdTe-based optoelectronic devices, which employ nonequilibrium photoexcited carriers to improve the performance.

The non-toxic nature, low cost, and excellent optical properties make oxide-based perovskites potential candidates for solar cell applications. The full potential linearized augmented plane wave approach is applied to explore the structural, electronic, optical, and thermoelectric properties of Ba₂XTiO₆ (X = Hf, Ce, and Te) for solar cell applications. As demonstrated by an elastic study, Ba₂HfTiO₆ is brittle, while Ba₂CeTiO₆ and Ba₂TeTiO₆ are ductile. The anisotropic values of Ba₂HfTiO₆, Ba₂CeTiO₆ and Ba₂TeTiO₆ are 1.14, 0.67 and 0.80 respectively. The electronic bandgap values of Ba₂HfTiO₆, Ba₂CeTiO₆, and Ba₂TeTiO₆ are computed as 3.44 eV, 2.96 eV, and 1.26 eV using the Tran-Blaha-modified Becke–Johnson approach. Moreover, the bandgap of Ba₂TeTiO₆ is compatible for solar cell applications. Optical investigation demonstrates that Ba₂TeTiO₆ shows maximum absorption in visible light among the studied perovskites. Lastly, the transport properties exhibit figure of merit values of 0.73, 0.77 and 0.81 for Ba₂HfTiO₆, Ba₂CeTiO₆, and Ba₂TeTiO₆ respectively. Consequently, with the bandgap falling in the visible region and high figure of merit among the studied perovskites, Ba₂TeTiO₆ emerges as the most suitable candidate for solar cell applications based on its electronic, optical, and thermoelectric properties.

This paper explores the utilization of matched coordinates for the comprehensive analysis of self-assembled cylinders, specifically focusing on a crossed grating with circular cross section within a hexagonal lattice. By incorporating the matched coordinate technique into the Fourier modal method (FMM), the paper addresses the limitations associated with staircase approximations when solving Maxwell’s equations in a curvilinear coordinate system. The study demonstrates that the proposed transformation significantly enhances the efficiency and speed of FMM, particularly in extracting optical characteristics such as reflection and transmission coefficients. Through a comparative analysis of a hexagonal lattice comprising air-suspended cylindrical resonators with a dielectric constant of 2, the proposed technique is shown to achieve comparable accuracy while utilizing only (40%) of the harmonics required by conventional methods. As a result, this approach offers substantial computational cost reductions of up to an order of magnitude.

Moore’s law, along with the International Roadmap for Devices and Systems, continues to guide the scaling of devices below 10 nm. The challenges posed by such small-dimensioned devices form the basis of the present work. A junctionless MOSFET with a triple-metal gate structure is proposed as an alternative to conventional single-gate bulk MOSFETs for future CMOS technology. The present work investigated the direct current and analog/radio frequency characteristics including the drain current (({I}_{{text{D}}})), transconductance ({(g}_{m})), transconductance generation factor (TGF), cut-off frequency ({(f}_{T})), frequency–transconductance product (FTP), transit time ((tau ),) and the total resistance of the source region, drain region, and channel ({(R}_{{text{SD}}+{text{CH}}})) for triple-metal (TM) inversion-mode (IM) and junctionless (JL) cylindrical gate-all-around (CGAA) silicon nanowire (SiNW) MOSFETs with 3-nm gate length using the Silvaco ATLAS 3D TCAD tool. The non-equilibrium Green’s function and the self-consistent solution of the Schrödinger and Poisson equations were considered. The channel was taken to be lightly doped in the case of the IM TM CGAA SiNW device. The effect of the TM gate work function engineering for a SiNW channel with a diameter of 3 nm and gate oxide (({{{text{Al}}}_{2}{text{O}}}_{3})) thickness of 0.8 nm was investigated with respect to ({I}_{D}),({ g}_{m}), TGF, ({f}_{T}), (tau), FTP, and ({R}_{{text{SD}}+{text{CH}}}), and a comparative study between the IM TM and JL TM CGAA SiNW devices was carried out with respect to these parameters. For the JL device, optimization of the doping concentration was performed to obtain the same (i) I_ON current and (ii) threshold voltage (V_TH) as the IM device. An 8.61- and 5.72-fold reduction in I_OFF was seen for the same I_ON and V_TH for the JL versus the IM device. It was found that the TM gate variation led to a reduction in drain-induced barrier lowering (DIBL) in the IM and JL devices. The JL SiNW showed much lower DIBL of ~39.49 mV/V, a near-ideal subthreshold slope (SS) of ~60 mV/dec, and higher ({{text{I}}}_{{text{ON}}}/{{text{I}}}_{{text{OFF}}}) current ratio of ~2.98 × 10¹². which is much better than the values reported in the literature for CGAA devices. Also, the JL SiNW device was found to perform better than the IM SiNW device in terms of SS, DIBL, ({{text{I}}}_{{text{ON}}}/{{text{I}}}_{{text{OFF}}}), ({g}_{m},) TGF, f_T, (tau), FTP, and ({R}_{{text{SD}}+{text{CH}}}).

Due to the growing need for higher speed data, the 5G terrestrial heterogeneous wireless network deployments are expected to happen quickly throughout the world in the next decade. In such type of networks, mm-wave small-cells overlapped the sub-6 GHz macro-cells being used to serve to population-rich areas. Subsequently, many problems appear with the antenna design technologies. The presented antenna is functioning at a frequency range from 24.8 to 31.6 GHz, with a 24% bandwidth and 8.5 dB peak gain at 27 GHz. It encompasses the complete 28 GHz frequency band utilized through 5G applications. Consequently, fifth-generation communication systems are best suited for it. The proposed Hamiltonian deep neural network optimized with pelican Optimization Algorithm-fostered Substrate-Integrated Waveguide Antenna Design for 5G (SIW-HDNN-POA-5G) is implemented, and performance of proposed technique is estimated based on several metrics, including resonant frequency (GHz), reflection coefficient (S11 in dB), mean absolute error (MAE), and root mean square error (RMSE). The proposed SIW-HDNN-POA-5G method provides 24.36%, 33.55% and 44.22% higher gain and 43.21%, 38.87% and 25.65% lesser mean absolute error comparing to the existing designs, like Design of Zero Clearance SIW End fire Antenna Array Based on Machine Learning-Assisted Optimization (SIW-MLAO-5G), SIW-Fed Wideband Filtering Antenna for Millimeter-Wave Applications (SIW-5G-MLOM), and Compact SIW Fed Dual-Port Single Element Annular Slot MIMO Antenna for 5G mm Wave Applications (SIW-FWFA-MMWA), respectively.

In this paper, the dispersion characteristics of slotted photonic crystal waveguides (SPCWs) have been estimated for any arbitrary set of structural parameters using machine learning-based artificial neural network (ANN). The machine learning-based technique yields faster solutions of the three-dimensional eigenvalue equations, which otherwise require substantial time using the conventional plane wave expansion (PWE)-based numerical simulations. Most importantly, the novel contribution of the work lies in estimating the structural parameters of the SPCWs from the given specifications of the dispersion characteristics through an inverse computation. A simple feed-forward neural network has been employed for both the forward and inverse estimations. The computation performances using both the ANN model and PWE simulations are analyzed and compared. The research offers significant implications for the field of photonics. By employing machine learning techniques, particularly ANNs, researchers and engineers can swiftly and efficiently analyze the dispersion properties of SPCWs, facilitating rapid prototyping and optimization of photonic devices. Additionally, the capability to infer structural parameters from desired dispersion characteristics streamlines the design process, potentially leading to the development of customized waveguides tailored to specific applications.

Fractional capacitors, commonly called constant-phase elements or CPEs, are used in modeling and control applications, for example, for rechargeable batteries. Unfortunately, they are not natively supported in the well-used circuit simulator SPICE. This manuscript presents and demonstrates a modeling approach that allows users to incorporate these elements in circuits and model the response in the time domain. The novelty is that we implement for the first time a particular configuration of RC elements in parallel in a Foster-type network with SPICE in order to simulate a constant-phase element across a defined frequency range. We demonstrate that the circuit produces the required impedance spectrum in the frequency domain, and shows a power-law voltage response to a step change in current in the time domain, consistent with theory, and is able to reproduce the experimental voltage response to a complicated current profile in the time domain. The error depends on the chosen frequency limits and the number of RC branches, in addition to very small SPICE numerical errors. We are able to define an optimum circuit description that minimizes error while maintaining a short computation time. The scientific value is that the work permits rapid and accurate evaluation of the response of CPEs in the time domain, faster than other methods, using open source tools.