Journal of Computational Electronics最新文献

A two-port microstrip antenna integrated with a metasurface (MS) absorber is designed and examined in this paper. MS placement below the 2-port antenna absorbs the normalized EM waves as well as improves the gain level to above 3.0 dBi. Loading of cross slots produces circular polarization features between 837 and 889 MHz. Reverse orientation of the slots on the patch enhances the separation by 25 dB. Simulated, experimental, and ML prediction confirm that the designed antenna works between 715 and 977 MHz. A Bbroadsided far-field pattern and good values of the MIMO parameters make the proposed antenna applicable for UHF RFID applications.

In this seminal work, we propose a novel-guided wave long-range surface plasmon resonance (GW-LRSPR) sensor. The multilayer sensor structure combines 2S2G prism, cytop, BaTiO₃, and silver (Ag). The inclusion of barium titanate (BaTiO₃: perovskite material), a material with high permittivity and piezoelectric properties, significantly enhances the imaging sensitivity (S_imag) of the proposed GW-LRSPR sensor as it allows for the tuning of the plasmonic response through electrical or mechanical stimuli. Additionally, the use of a Cytop layer as an insulating and protective dielectric layer further enhances the sensor’s durability and optical performance. By incorporating the BaTiO₃ layer, the sensor achieves a maximum S_imag of 73,031 RIU⁻¹, significantly higher than the 44,542 RIU⁻¹ obtained without the layer. Hence, the GW-LRSPR sensor demonstrated strong capability in analyte detection. The sensor also exhibits a figure of merit (FoM) of 7.3 × 10⁶ RIU⁻¹, with detection accuracies (DA) of 169.49/° and 185.18/° for the LRSPR and GW-LRSPR sensors, respectively. Overall, the proposed GW-LRSPR sensor improves imaging sensitivity by nearly 64% compared to the LRSPR sensor.

This study systematically investigates the spontaneous emission spectra of GaAs_1-xBi_x/GaAs double quantum wells (DQWs) through an eight-band k•p model, elucidating the dependence of the emission characteristics across varying well widths, barrier thicknesses, Bi compositions, doping densities, and temperatures. The emission peak intensity decreases and redshifts with increasing well-width due to weakened quantum confinement, with DQWs showing a more gradual intensity decay than SQWs. The GaAs barrier thickness of the DQWs is found to affect minimally the spontaneous emission spectra, but a GaAs_0.95Bi_0.05/GaAs DQW, where the interwell barrier is a GaAs_0.99Bi_0.01 barrier layer, demonstrates the tunability of the emission intensity with varying barrier thickness. Varying the Bi composition in the GaAs_1-xBi_x wells of the DQWs shows invariant peak intensity across low compositions (0.01–0.05) and a pronounced redshift over 30 meV. On the other hand, simultaneous variation of Bi compositions in both wells enables a monotonic redshift. This shows a method to realize a broadband frequency tunability. A thicker interwell GaAs_1-xBi_x barrier layer, for a specified Bi composition, can result in a relatively larger redshift. Increased carrier density boosts peak intensity. As the temperature increases, the peak intensity decreases, and the peak position undergoes a redshift. Notably, DQWs exhibit slower decay rates at high energies compared to SQWs. Furthermore, under equivalent confinement conditions, DQWs demonstrate superior emission rates relative to SQWs.

With the continuous research on electromagnetic (EM) metasurfaces, it has been found that a variety of EM modulation functions can be realized by polarization multiplexing and frequency multiplexing, thus forming multifunctional EM metasurfaces. However, the inherent property of EM wave propagation direction has not been effectively utilized to realize multifunctional EM devices that depend on propagation direction. Here, a multifunctional coding metasurface is proposed based on Fourier convolution operation that can achieve different functions in opposite propagation directions. As a proof of concept, the proposed multifunctional metasurface is capable of achieving orbital angular momentum (OAM) beam with mode number l = 1 and divergence angle ± 6° in the upper half-space when a circularly polarized EM wave at 13 GHz is incident. On top of this the Fourier convolution operation is superimposed to achieve anomalous reflection of the OAM beam and OAM beam splitting. When X-polarized EM wave at 12.2 GHz is incident, beam splitting can be achieved in the lower half-space. The experimental results are in good agreement with the numerical results, and this multifunctional metasurface provides a new way for the development of new multifunctional devices and paves the way for their use in other fields such as antennas and communications.

This study develops a comprehensive optical–electrical model to identify the efficiency-limiting mechanisms in CdTe_1−xSe_x solar cells. The aim is to provide a unified understanding of how various recombination pathways, tunneling-enhanced, Auger, Shockley–Read–Hall (SRH), interface, and non-radiative recombination, collectively impact device performance. While prior research typically focuses on isolated mechanisms, our integrated approach reveals their combined influence on efficiency losses. The model shows strong agreement with experimental data and serves as a fitness function for a multi-objective genetic algorithm (MOGA), enabling systematic optimization of device parameters. Our results identify Ga₂O₃ as a promising Cd-free ETL, achieving an optimized efficiency of 25.8%, with J_SC = 24.93 mA/cm², V_OC = 1.27 V, and FF = 80.28%. These findings offer valuable insights into degradation mechanisms and provide a pathway for designing high-performance, environmentally friendly CdTe_1-xSe_x solar cells.

This study presents a comprehensive theoretical and numerical investigation into the local field enhancement factor (LFEF) and optical bistability (OB) in ZnTe@Ag core-shell nanostructures embedded within dielectric host matrices. Using the quasi-static approximation, Laplace’s equation was analytically solved for both spherical and cylindrical geometries under appropriate boundary conditions. The Kerr-type nonlinearity of the host medium was incorporated to model third-order nonlinear optical effects. The dielectric response of the silver shell was described using a size-dependent Drude model. Numerical simulations revealed that spherical nanocomposites exhibit significantly stronger field enhancement and lower OB threshold intensities compared to cylindrical counterparts. Additionally, increasing the host dielectric constant or core-shell radius ratio resulted in pronounced shifts in resonance peaks and broadened bistability regions. The LFEF was found to be highly tunable with respect to geometry, size, and material composition, reaching intensities up to three times greater in spherical structures. These findings provide crucial insight into the geometric and dielectric modulation of nonlinear optical behavior, supporting the design of nanostructures for use in optical sensing, memory, and switching devices.

Driven by the growing imperative for energy-efficient computing, reversible logic gates have gained significant attention for their ability to reduce energy dissipation. These gates are essential in advanced domains such as quantum computing, DNA computing, nanotechnology, and energy-aware CMOS design. This study presents an optimized 4 × 4-bit complex Vedic multiplier designed using reversible logic, alongside modular implementations of a 4 × 4-bit Vedic multiplier, unified 8-bit adder–subtractor and two variants of a 4-bit carry-save adder. The proposed architectures are evaluated based on key performance metrics, including ancilla inputs, garbage outputs, quantum cost, and gate count. Furthermore, an entropy-based validation grounded in Shannon’s information theory confirms logical reversibility of the circuits, reinforcing their potential for ultra-low-power and quantum computing applications.

In this work, an electric field-tuned strategy based on dual-atom doping is proposed to achieve precise control of spin-dependent thermoelectric transport in SiC nanoribbons (SiCNRs), using first-principles calculations. The study reveals that dual-atom doping at specific sites of zigzag SiCNRs can regulate spin-dependent transmission coefficients, leading to the emergence of “X"-shaped transmission spectra near the Fermi level. Under this condition, the two spin channels exhibit pronounced opposite signs in their Seebeck coefficients, inducing spin-polarized currents with opposite flow directions. By applying a gate voltage to the central scattering region, the density of states distribution in the doped system can be precisely modulated, thereby enabling a pronounced spin Seebeck effect. The spin Seebeck coefficient reaches a remarkable value of 225 µV/K, significantly surpassing that of conventional doped SiC nanoribbons((sim)100 µV/K) and edge-doped graphene nanoribbons((sim)150 µV/K). This dual-atom doping strategy establishes a new paradigm for designing room-temperature spin caloritronic devices with programmable spin current configurations.

In this paper, a metasurface design is proposed, which can be reconfigured to operate in two modes. In Mode 1, it functions as a polarization-selective transmitter/reflector in the 3.19(-)3.7 GHz range, transmitting x-polarized waves and reflecting y-polarized waves when the RF switch is OFF, while reflecting both when ON. In Mode 2, it functions as a polarization-selective absorber/reflector by integrating an absorber to the structure. It allows x-polarized waves to be either absorbed or reflected based on the switch state, while y-polarized waves are always reflected. The four-layer metallic structure integrates PIN diodes with a simplified embedded bias network, minimizing complexity and achieving 99.7% absorptivity. Theoretical validation is provided through surface current distribution and an equivalent circuit model, with experimental measurements confirming performance. It features a slimmer design, improved angular stability, and a simplified DC biasing network, demonstrating a multifunctional solution for advanced electromagnetic applications.

A gas sensor based on a hexagonally organized core photonic crystal fiber (PCF) is presented in this research. One of the deadly and hazardous gases that contributes to environmental air pollution is hydrogen cyanide. This work presents the design of a novel PCF that provides minimal confinement loss and great sensitivity in the absorption frequency of hydrogen cyanide gas (HCN). With a hexagonal core and an outside cladding that has been filled with HCN gas, the suggested sensor is made of four layers of circular air holes in the cladding region. Version 5.4 of the COMSOL Multiphysics Software is utilized as a simulation and design tool. The findings are simulated using the finite element method (FEM). The result shows that at a frequency of 0.75 THz, the PCF provides a low confinement loss of zero for maximum input frequency and a high relative sensitivity of 91%. The effect of raising the HCN concentration on confinement loss and relative sensitivity is examined. Compared to existing sensors, the proposed PCF’s superior sensitivity and low confinement losses suggest that this optical structure could be a viable option for detecting this gas in both industrial and medical applications. We are certain that the sensor’s contribution to useful applications and its optimized geometrical structure will make it easy to manufacture. Additionally, our suggested PCF fiber will be perfect for a variety of businesses in the terahertz (THz) zones.