Nowadays, one of the appealing choice of transistors for the next generation of high power devices is, AlGaN/GaN high-electron-mobility transistor (AlGaN/GaN-HEMT). Prior to now, numerous experiments were conducted utilizing various gate engineering techniques to propose high threshold voltage enhancement-mode HEMT architectures. In this paper, two new e-mode HEMT structures are proposed by taking motivation from our previously reported structure of Recessed p-GaN gate HEMT. By incorporating p-doped buried layer with recessed p-GaN gate in one HEMT structure, the threshold voltage is significantly increased. In first experiment, a p-doped GaN region is buried in to the Gallium Nitride (GaN) substrate of conventional p-GaN gate HEMT. In second experiment, a p-GaN buried layer is inserted in to GaN substrate of recessed p-GaN gate HEMT. V th of above 3V is obtained from the proposed structures, which is suitable to be implemented for high-frequency power switching applications. The proposed structures provides flexibility to tune V th and I d. The digital circuit compatibility is also tested by using both the proposed structures in a resistive-load inverter circuit. The transient analysis confirms that the HEMTs work properly in inverter circuit and the VTC analysis shows 98.5% of output voltage swing at input voltage of 5V. Highest NM H and NM L is measured as 2.85V and 2.65V respectively. The device simulation, calibration and circuit simulation is done in Silvaco TCAD software.

It’s hard to accurately consider various operating factors for the traditional single event transient (SET) SPICE modeling. This paper proposes a novel method based on neural network. The proposed method can unify the intricate data correlations among drain voltage, linear energy transfer (LET), temperature, strike position, time, and drain transient current in a single model with high accuracy. Technology computer aided design (TCAD) simulation is used to get the original SET data for training. The genetic algorithm (GA) optimized back propagation (BP) neural network established herein has a root mean square error (RMSE) of less than 2.0042%. This optimized neural network is converted to SET current SPICE model through Verilog-A language and its practicality has been verified through circuit simulation of a two-input NAND gate.

This study analyses various factors that affect the threshold voltage of MOSFETs at deep cryogenic temperatures, including band-tail state, field-assisted ionization, and interface traps. Based on the analysis, a new model is developed for Si-based MOSFETs covering a wide temperature range from 10K to 300 K. The model's validity is confirmed through experiments of bulk silicon and FDSOI MOSFETs.

Gallium nitride (GaN) high electron mobility transistors (HEMTs) have attracted considerable attention due to high electron mobility, wide bandgap, and other advantageous properties. However, the self-heating that occurs at high power densities has emerged as a significant challenge that restricts HEMTs’ potential in high-performance applications. This study introduces a novel approach for extracting channel temperature distributions and thermal resistance, which considers the bias-dependence of the heat source model and the electro-thermal coupling among multiple gate fingers. The thermal resistance extracted by the optimized thermal model in this study differs from the traditional thermal model by 14.8% under a power density of 8W/mm and a base temperature of 1 0 0 ◦ C . The precision of the model is validated through infrared (IR) thermography, showing only a 1.76% discrepancy in the peak surface temperature of the filtered model compared to the measurement. To evaluate the model’s applicability across various conditions, comparisons are conducted between the model’s predictions and measurements across a range of ambient temperatures and power dissipation, revealing maximum errors of 4.1% at 7 5 ◦ C and 2.7% at 1 0 0 ◦ C . Finally, the influence of thermal boundary resistance (TBR) on the total thermal resistance is explored to provide guidance for device modeling and thermal management.

In order to address the challenges of complex process and low precision in traditional device modeling, based on the double hidden layer conjugate gradient back propagation neural network (CG-BPNN) and the double hidden layer Levenberg-Marquardt back propagation neural network (LM-BPNN), two small signal models are proposed and analyzed for the gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) here. At first, the scattering parameters (S-parameters) of GaAs pHEMT are divided into training set and test set randomly. Experimental results show that the CG-BPNN is better than another S-parameters when predicting ImS12 with mean square error (MSE) of 1.0449e-05, while LM-BPNN predicts ImS12 with MSE of 3.0954e-06. Meanwhile, the MSE of CG-BPNN is higher than LM-BPNN when predicting all the S-parameters. In addition, it shows a smaller fluctuation range for the error curve of LM-BPNN, which is more stable than the CG-BPNN. Therefore, the double hidden layer LM-BPNN is the better choice to model the small signal of GaAs pHEMT.

─ We present the derivation of new closed-form equations for the probability density function (PDF) and cumulative distribution function (CDF) of the product of the ratio of α-µ variates and the gamma variate. These findings have implications for the performance analysis, modeling, and simulation of cooperative diversity systems in fading situations where the signal envelope is influenced by rapid and slow fading. In the presented model fast fading affects the envelope of co-channel interference in this system also. A particular special case of the α-µ distributed variable (Rayleigh, Weibull, and Nakagami-m distributed variables), in several different transmission contexts is modeled. Theoretical results are supplemented by numerical results that are visually depicted.

A novel multi-conductor electromagnetic coupling model for the sensitive-wire subject to driven wire in a high-precision machining workbench is proposed in this paper. The general coupling model for an N-wire system is derived and is used to evaluate the wire coupling effect. Furthermore, 4-wire and 3-wire models are demonstrated to verify the accuracy through full-wave electromagnetic simulation below 10 MHz. The results show that the error between the proposed method and the full-wave electromagnetic simulation is less than 10%, demonstrating the high efficiency and accuracy of the proposed method. When the parameters of the driven power wire and the most sensitive wire are fixed and the parameters of neighboring wires are swept, the maximum fluctuation of the induced current on the most sensitive wire is 6.1 dB. The efficient calculation method proposed in this work helps reduce the risk of electromagnetic interference in complex electronic systems and improves the design efficiency of wires. It is promising to become a high-performance method with high efficiency and precision.

An algorithm is proposed to implement digital peeling to determine dominant time constants of an exponential transient process. The method is simpler to implement and reduces computational time to a large extent in comparison to other techniques widely used. Apart from a synthetic test function, the algorithm has been implemented on reported experimental transient decay curves of Cs 2HfCl 6 (CHC) single crystal scintillation to verify its efficacy. Finally, drain current detrapping transients of unpassivated AlGaN/GaN high electron mobility transistors (HEMTs) are analysed to determine the trap energy levels and concentrations. The validation of this digital peeling technique is also carried out by comparing with conventional method of time constant extraction from HEMT current transients. The extracted exponentials from the transient data efficiently fits well with the experimental data and can be extensively used for transient analysis. The digital peeling technique has wide applicability and can be used to analyze all exponential processes which occur in all domains of science.

This study presents a comparative analysis of radar cross section (RCS) simulations using Ansys High-Frequency Simulation Software (HFSS) and MATLAB. The primary objective is to evaluate the accuracy and consistency of RCS calculations performed by these two software tools for metallic cylinders. Metallic cylinders are selected as radar targets due to their well-defined and standardized shapes, which enable easier modeling and comparative analysis. To validate the RCS simulations, actual RCS measurements were conducted on an airport runway. The measurements took place at Kuala Lumpur International Airport (KLIA) using an FOD detection system operating at 93.1 GHz. By comparing the measured RCS data with the simulations results, the agreement and reliability of the simulation techniques were assessed, considering metallic cylinders of six different sizes. The findings indicate that the RCS values obtained from measurements align with the simulation results, exhibiting a similar RCS pattern. Both simulations exhibit minimal discrepancies, ranging between 0.01 to 0.1 dBsm. Through the analysis of the simulation results and measurements, valuable insight were gained regarding the performance and effectiveness of HFSS and MATLAB in predicting RCS values. Consequently, this study contributes to the understanding and validation of RCS simulation techniques and their practical applicability in real-world scenarios.

This paper, presents a 4×4 BM based on four direction switch BM antenna array. The proposed design operated at 3.5 GHz. The use of multi-beam antennas or switched-beam antenna arrays (SAAs) promised users of high-gain and large coverage areas for 5G technologies. The BM was implemented by combining 3-dB BLC, two crossovers, and 45 o phase shifters fabricated on the RT5880LZ substrate, with using a triangular slot and T-shape based on the BM design. The proposed design focused on the miniaturization and enhancement of the bandwidth. The return loss and isolation were better than -15 dB at all the ports, according to the simulated and measured result showed that with excellent insertion loss -6.1 ± 2 dB. A fractional bandwidth of 49.7% and the overall dimension were reduced to 56% as compared to the conventional BLC and crossover. Hence, the proposed design of BM performed an excellent size reduction of 80% and improvement bandwidth up to 836 MHz compared to the traditional BM. The switched beam directions were measured at -34 o, -40 o, +32 o and +35 o at 3.5 GHz for each input port of 1-4 excitation. The proposed design BM is suitable of 5G application.