Power Gain Research Articles

A LiDAR-Based Active Yaw Control Strategy for Optimal Wake Steering in Paired Wind Turbines

In this study, we investigate a yaw control strategy in a two-turbine wind farm with 3.5 MW turbines, aiming to optimize power management. The wind farm is equipped with a nacelle-mounted multi-plane LiDAR system for wind speed measurements. Using an analytical model and integrating LiDAR and SCADA data, we estimate wake effects and power output. Our results show a 2% power gain achieved through optimal yaw control over a year-long assessment. The wind predominantly blows from the southwest, perpendicular to the turbine alignment. The optimal yaw and power gain depend on wind conditions, with higher turbulence intensity and wind speed leading to reduced gains. The power gain follows a bell curve across the range of wind inflow angles, peaking at 1.7% with a corresponding optimal yaw of 17 degrees at an inflow angle of 12 degrees. Further experiments are recommended to refine the estimates and enhance the performance of wind farms through optimized yaw control strategies, ultimately contributing to the advancement of sustainable energy generation.

Impact of electron velocity modulation on microwave power performance for AlGaN/GaN HFETs

In this study, we demonstrate the effects of electron velocity modulation (Δve/ΔVgs) on the microwave power performance for AlGaN/GaN HFETs. In order to conduct the experiments, AlGaN/GaN HFETs with gate lengths ranging from 500 to 80 nm were fabricated. Electron transport was investigated by coupling a drift-diffusion solver with the Monte Carlo method. As gate lengths (Lg) varied from 500 to 200 nm, the increased polarization Coulomb field scattering led to an increase in Δve/ΔVgs and the stronger electric field (E) increased ve and enhanced the transconductance (gm), which in turn led to a greater power gain (Gp) in the HFETs. The higher power output (Pout) was also due to the increased ve that boosted the saturated output current (Ids,sat). The unique phenomenon that occurs from electron velocity modulation of AlGaN/GaN HFETs at electron densities (ns) < 3.42 × 1012cm−2 can be used as an effective mechanism to enhance the power gain of AlGaN/GaN HFETs.

A novel 5.1–7.1 GHz front-end power amplifier for wireless applications with [formula omitted] dB Error Vector Magnitude

A Power Amplifier (PA) is proposed for WiFi-6E applications, specifically designed to support WLAN 802.11ax standard to achieve significant linear power. The proposed PA is designed to operate in the entire 5 GHz and 6 GHz frequency bands. The design involves a two-stage configuration, initial stage adopts a linear driver, while the subsequent amplification stage is structured as a differential cascode. UMC 65 nm CMOS process technology is used to design a PA in commercial Cadence platform. The layout occupies core area of 0.24 mm2. Proposed PA delivers a power gain of 20 dB, Power Added Efficiency (PAE) of 19% and 1 dB compression point (P1dB) is of 24.5 dB is achieved for continuous wave (CW) signal. For the 802.11ax source, the recorded average power output (Pavg) is 17.1 dBm at an Error Vector Magnitude (EVM) ≤−35 dB, across the 5–7 GHz. The PA delivers Pavg of 10 dBm at worst corner case in PVT variation analysis. While the majority of recent works in WLAN PA confines the investigation to 5 GHz band, this paper broadens the scope by extending the study by up to 7.050 GHz in 6 GHz band. The incorporation of 6GHz band enables WiFi-6E to utilize up to 1,200 MHz of unencumbered spectrum, significantly enhancing the available bandwidth relative to earlier WiFi standards. The increased bandwidth facilitates high data rate applications, such as streaming and gaming.

The Biomechanical differences in maximum snatch weight between elite and sub-elite weightlifters: A one-dimensional statistical parameter mapping study

Background: Current research primarily relies on discrete data collected at specific time points to analyze the weightlifting process, often overlooking the impact of continuous temporal changes on athletic performance. Purpose: This study aimed to quantitatively analyze the one-dimensional kinematic patterns of maximum snatch weight actions in elite and sub-elite weightlifters using statistical parameter mapping (SPM). It explores kinematic differences in snatch actions between elite and sub-elite weightlifters, which assists in summarizing the technical characteristics of elite athletes. Methods: Two cameras recorded three successful maximum snatch attempts of 10 elite and 10 sub-elite weightlifters at the World Weightlifting Championships and Chinese Olympic selection competitions. Simi Motion 10.2 was used for kinematic analysis. SPM was employed for comparative analysis of snatch kinematics among different levels of weightlifters, and independent sample t-tests were used for phase duration proportions. Results: Elite weightlifters showed significant advantages in multiple movement phases: smaller knee joint angles in M1 phase (p < 0.001, 35.82%–78.45%) and M3 phases (p = 0.047, 17.47%–24.74%; p = 0.036, 30.92%–49.38%; p = 0.040, 50.93%–65.85%); lower vertical body center of gravity (COG) height in M1 phase (p = 0.019, 0.00%–51.08%), M3 phase (p = 0.046, 48.27%–100.00%), and M5 phase (p = 0.045, 38.49%–59.54%); closer displacement between barbell COG and body COG in M1 phase (p = 0.006, 0%–38.18%; p = 0.048, 43.91%–48.94%) and M2 phase (p = 0.026, 0%–100%); greater barbell acceleration in M5 phase (p < 0.001, 0%–94.61%); and slower barbell descent speed in M6 phase (p = 0.001, 0%–30.58%; p = 0.046, 44.57%–51.37%; p = 0.048, 67.16%–72.41%). Moreover, elite weightlifters exhibited significantly higher phase duration proportions in M1 phase (p = 0.034, d = 1.03) than sub-elite weightlifters. Conclusion: Elite weightlifters demonstrated longer distance and time exerting work on the barbell in M1 phase, less energy consumption in barbell ascent in M2 phase, and greater upward power gain for the barbell in M1 and M3 phases. They showed faster squat-to-barbell catching speed in M4 phase and excellent braking and precise squat-to-barbell catching capabilities in M5 and M6 phases.

Multidimensional QPSK symbol modulation scheme based on random sequence extraction for D-band photonics-aided wireless communication

We propose a multidimensional (MD) quadrature phase shift keying (QPSK) symbol modulation and demodulation scheme based on random sequence extraction, which overcomes the limitations of traditional QPSK signals in performing probabilistic shaping. Unlike probabilistic shaping (PS) and geometric shaping (GS), our approach does not require modifications to the existing digital signal processing (DSP) architecture; it only necessitates the addition of sequence modulation and demodulation modules. Additionally, the source entropy (SE) can be flexibly adjusted. An experimental verification was conducted in a 50 m, 150 GHz photonics-aided wireless communication system. The results show that, under the same net data rate, the random sequence extraction QPSK scheme can achieve a maximum optical power gain of 0.7 dB. These findings indicate that the random sequence extraction QPSK (SE-QPSK) scheme can effectively enhance system performance, providing a promising outlook for future wireless communication.

An active two-stage class-J power amplifier design for smart grid’s 5G wireless networks

<span>The wireless communication networks in the smart grid’s advanced metering infrastructure (AMI) applications need 5G technology to support large data transmission efficiently. As the 5G wireless communication network’s overall bandwidth (BW) and efficiency depend on its power amplifier (PA), in this work, a two-stage class-J power amplifier’s design methodology that operates at 3.5 GHz centre frequency by utilizing the CGH40010F model gallium nitride (GaN) transistor is presented. The proposed design methodology involves proper designing of input, output, and interstage matching networks to achieve class-J operation with improved power gain over desired BW using the advanced design system (ADS) electronic design automation (EDA) tool and estimating its integration feasibility through active element-based design approach using the Mentor Graphics EDA tool. The proposed PA provides 54% drain efficiency (D.E), 53% power added efficiency (PAE) with a small signal gain of 27 dB at 3.5 GHz and 41 dBm power output with 21 dB of improved power gain across a BW of around 400 MHz using 28 V power supply into 50 Ω load. By replacing the two-stage PA's passive elements with active elements, its layout size is estimated to be (15.5×29.2) μm2 . The results of the proposed PA exhibit its integration feasibility and suitability for the smart grid’s 5G wireless networks.</span>

Exploring the Impact of Ni Doping in Tuning the Bandgap, Electronic, Optoelectronic and Photocatalytic Properties of ZnFe2O4

AbstractThe exploration of semiconductor nanostructures utilizing mixed metal materials is an emerging area of study across fields including field‐effect transistors, chemical sensors, photodetectors, photocatalysts, and many more. In this study, Schottky diodes based on ZnFe2O4 (ZFO) were constructed with an aim to tune their electronic and optoelectronic characteristics. Here, Ni doping facilitated the tuning of electronic properties, leading to a significant increase in the rectification ratio from 238 to 1172, along with a reduction in the potential barrier height from 0.67 V to 0.65 V. This is attributed to Ni's role as a charge carrier in ZFO, enhancing carrier concentration, confirmed by Mott‐Schottky analysis. The 5 mol % Ni‐doped ZFO also exhibited remarkable light sensitivity, with its rectification ratio surging to 1795 under illumination, four times that of the undoped version. Additionally, its photo‐sensitivity soared to 42.46 %, nearly quadrupling the undoped device's performance, and its power gain impressively climbed to 38.4 %, which is over twelvefold the undoped sample's output. Furthermore, the diode responds strongly to optical illumination, making this structure suitable for use as a photodiode or photosensor. Apart from that by employing a doping strategy, we achieved 64.61 % degradation of methylene blue dye under visible light in 120 minutes, compared to 36.85 % for the undoped sample. These indicate that hydrothermally synthesized Ni‐doped ZFO is promising for visible light‐driven multifunctional applications.

Selective testing and its effect on false discovery rate controlling procedures under discrete framework

The support of the p-value corresponding to a discrete test-statistic is a finite isolated subset of the unit interval. In differential gene expression studies with RNA-sequence datasets, multiple discrete tests are performed. The objective of such studies are to identify differentially expressed genes with a control over a measure of false discoveries. We suggest to remove hypotheses corresponding to the p-values having minimum support-point greater than the threshold of that overall measure. We argue this suggestion and present methods of filtering the set of hypotheses for two useful testing scenarios. Simulation experiments show gain in power of the multiple testing procedures when applied to the filtered set of hypotheses. We also demonstrate the method with two real datasets, related to the study of HIV and mammary gland.

A 132–170 GHz high-gain driving amplifier utilizing asymmetric broadside coupled line in 40-nm CMOS

This paper presents a driving amplifier (DA) utilizing the proposed asymmetric broadside coupled line. In contrast to conventional coupled line, the balun devised with proposed asymmetric coupled line and enhanced wideband balance compensation technique is utilized, thereby achieving wideband impedance matching and mitigating insertion loss. Additionally, the utilization of the lossy over-neutralization technique substantially enhances the power gain of amplifiers operating in the upper millimeter-wave band (150 GHz–300 GHz). The DA is fabricated utilizing a 40-nm CMOS process without aluminum layers. The fabricated amplifier demonstrates a compact total area of 0.135 mm2 (0.031 λ2), with a core area of 0.027 mm2 (0.0061 λ2). It achieves a high gain of 19.4 dB, high power of 11.05 dBm, and high power-added efficiency (PAE) of 11.05% at 160 GHz. Moreover, both the 3-dB power gain bandwidth and the 3-dB saturated power bandwidth extend from 132 GHz to 170 GHz, covering a bandwidth of 38 GHz. This configuration underscores the robust performance of the DA in the upper millimeter-wave band.

Numerical simulation of core shell dual metal gate stack junctionless accumulation mode nanowire FET (CS-DM-GS-JAMNWFET) for low power digital applications

In this paper, Core Shell Dual Metal Gate Stack Junctionless Accumulation Mode Nanowire FET (CS-DM-GS-JAMNWFET) is proposed, which has enhanced performance and is suitable for analog and digital applications. A high-k gate stack engineering, Hafnium Oxide (HfO2) is deployed in the outer as well as inner gate oxides of the core shell structure. The proposed device is compared with CS-DM-JAMNWFET, CS-SM-JAMNWFET, DM-GS-JAMNWFET, DM-JAMNWFET, and SM-JAMNWFET by maintaining a constant threshold voltage for all structures. The proposed CS-DM-GS-JAMNWFET provides a substantial reduction in subthreshold current with a high Ion/Ioff ratio as compared to other competent device structures. Also, the proposed device exhibits improvements in various parameters compared to the SM-JAMNWFET. It shows improvement in drain current (2.27 times), output conductance (2.14 times), subthreshold swing (0.94 times), transconductance (2.47 times), gate capacitance (2.00 times), cut-off frequency (1.24 times), intrinsic gain (12.95 times), current gain (1.46), Ion/Ioff ratio (6.15 times), unilateral power gain (1.09 times), maximum transducer power gain (1.08 times), Transconductance Generation factor (1.08 times), gain frequency product (14.61 times), transconductance frequency product (1.32 times), and gain transconductance frequency product (17.27 times). These benefits are due to combined advantages of the dual metal high-k dielectric HfO2 structure in core shell JAM FET, which enhances the device's gate dominance over the channel with high driving current.

Aerodynamic design and optimization analysis of a 200 kW radial-inflow turbine

Abstract In low-temperature waste heat recovery for organic Rankine cycle (ORC) power generation, the radial-inflow turbine (RIT) plays a crucial role. This study focuses on the preliminary design, three-dimensional simulations, and optimization of a 200 kW RIT for R245fa working fluid. The turbine’s preliminary design relies on selected empirical coefficients, leading to performance uncertainty. The performance of the turbine obtained from the initial design was evaluated using computer simulations, indicating that achieving outstanding isentropic efficiency and power targets solely relying on the design of empirical coefficients can sometimes be challenging. Design of Experiments (DOE) on five variables was performed using the Isight platform, highlighting rotor inlet blade height as crucial for turbine performance. The optimized RIT showed a 10.5% efficiency increase and 45.6 kW power gain. Entropy production analysis confirmed substantial improvement. Systematic theoretical calculations followed by DOE optimization effectively enhance turbine efficiency, providing valuable and innovative insights for satisfactory design solutions.

Auxotonic training in muscle strength and power performance of professional young volleyball players

Auxotonic training unexplained on isotonic and isometric muscular contraction combination to develop strength and power gain. The study aimed to investigate muscle strength and power changes of professional young volleyball players on the auxotonic training effect. Volleyball players divided in AUT (auxotonic group: 16.32 y, 1.72 m, 63.63 kg) trained over 8 week and per week 2 day performing isotonic + isometric contraction combination periodization and IKT (isokinetic group: 16.23 y, 1.69 m, 60.22 kg) performed only isokinetic contraction periodization. The linear muscle strength and power processes of training periodization preferred for maximize performance. The strength changes of this study resulted on AUT and IKT for 1RM strength test and activforce isometric muscular strength adaptation test were similar, however, AUT obtained high improvement power performance (p < .05). Auxotonic training developed on strength and power for AUT. Additionally, showing of comparison between AUT and IKT concluded CMJ (90°) ES = 1.09 very large, vertical jump ES = 1.31 very large and handgrip right ES = 0.05 small effect size. Based on the results we obtained, current auxotonic contraction was determined on resistance training applied to young volleyball players effective in strength and power development. Auxotonic training performed on young volleyball players will bring a perspective to the coaches and athletes work in this field as a resistance training model. The auxotonic training strategy for long term performance changes on outcomes of using aimed potential muscle isotonic + isometric contraction combination may be effective maximize strength and power performance.

A bias-corrected Srivastava-type test for cross-sectional independence

This paper proposes a test for cross-sectional independence with high dimensional panel data. It uses the random matrix theory based approach of Srivastava (2005) in the presence of a large number of cross-sectional units and time series observations. Because the errors are unobservable, the residuals from the regression model for panel data are used. We develop a bias-corrected test after adjusting for the contribution from the regressors. With the aid of the martingale central limit theorem, we prove that the limiting null distribution of the proposed test statistic is normal under mild conditions as cross-sectional dimension and time dimension go to infinity together. We further study the asymptotic relative efficiency of our proposed test with respect to the state-of-art Lagrange multiplier test. An interesting finding is that the newly proposed test can have substantial power gain when the underlying variance magnitudes are not identical across different units.

An enhanced broadband class-J mode power amplifier for 5G smart meter applications.

Background: With the tremendous increase in the usage of smart meters for industrial/ household purposes, their implementation is considered a crucial challenge in the Internet of Things (IoT) world, leading to a demand for emerging 5G technology. In addition, a large amount of data has to be communicated by smart meters efficiently, which needs a significant enhancement in bandwidth. The power amplifier (PA) plays a major role in deciding the efficiency and bandwidth of the entire communication system. Among the various modes of PAs, a newly developed Class-J mode PA has been proven to achieve high efficiency over a wide bandwidth by maintaining linearity. Methods: This paper proposes a Class-J mode PA design methodology using a CGH40010F-GaN device that operates at a 3.5 GHz frequency to meet the requirements of 5G wireless communication technology for the replacement of existing 4G/LTE technology used for advanced metering infrastructure (AMI) in smart grids. This research's main objective is to design the proper matching networks (M.Ns) to achieve Class-J mode operation that satisfies the bandwidth requirements of 5G smart grid applications. With the target impedances obtained using the load-pull simulation, lumped element matching networks are analyzed and designed in 3 ways using the ADS EDA tool. Results: The simulation results reveal that the proposed Class-J PA provides a maximum drain efficiency (D.E) of 82%, power added efficiency (PAE) of 67% with 13 dB small-signal gain at 3.5 GHz, and output power of 40 dBm (41.4 dBm peak) with a power gain of approximately 7 dB over a bandwidth of approximately 400 MHz with a 28 V power supply into a 50 Ω load. Conclusion: The efficiency and bandwidth of the proposed Class-J PA can be enhanced further by fine-tuning the matching network design to make it more suitable for 5G smart meter/grid applications.

Performance comparison of various end-to-end learning technologies with a bandwidth-limited OWC system

Recently, end-to-end (E2E) learning methodologies have garnered significant attention as a compelling approach to attain global optimal communication within the domain of 6 G native intelligent systems. Nevertheless, a precise evaluation of the diverse E2E techniques is still lacking, leading to uncertainties regarding their applicable scenarios and effectiveness. In this paper, we present a comprehensive comparison applying three advanced E2E methods including the autoencoder-based geometric shaping (AEGS) model, comprehensive autoencoder (CAE) model, and wave-wise auto-equalization (WWAE) model in a real bandwidth-limited optical wireless communication (OWC) system. A novel attention-based comprehensive noise joint channel estimator (ACNJCE) is proposed to serve as a universal channel model adaptable to the existing E2E methods. Based on traditional carrier-less amplitude and phase modulation (CAP) modulation, AEGS, WWAE, and CAE are compared under the conditions of 2 GBaud and 3 GBaud respectively. The final results demonstrate that the CAE exhibits the capability to autonomously allocate bandwidth and achieves the highest dynamic adjustment range, which is increased by 69% compared with CAP based on neural network (NN) equalization. In contrast, AEGS has obvious advantages in terms of received optical power (ROP) gain. Based on bit-power loading discrete multi-tone modulation (DMT) modulation, WWAE can effectively compensate the signal spectrum after modulation order optimization and finally achieves the highest data rate under the condition that the −3 dB bandwidth of the channel is only close to 1 GHz. The BER of WWAE with DMT at this rate is 25.2% of that using the NN equalization. Furthermore, experimental results under turbulent conditions reveal that AEGS exhibits superior and more stable performance amidst the perturbations caused by turbulence due to its ability to achieve end-to-end autonomous optimization while integrating traditional modulation and bringing additional shaping gain. According to our knowledge, this marks the first comprehensive evaluation and comparison of existing major E2E algorithms and traditional communication algorithms in a real OWC system.

Causal estimators for incorporating external controls in randomized trials with longitudinal outcomes

Abstract Incorporating external data, such as external controls, holds the promise of improving the efficiency of traditional randomized controlled trials especially when treating rare diseases or diseases with unmet needs. To this end, we propose novel weighting estimators grounded in the causal inference framework. As an alternative framework, Bayesian methods are also discussed. From trial design perspective, operating characteristics including Type I error and power are particularly important and are assessed in our realistic simulation studies representing a variety of practical scenarios. Our proposed weighting estimators achieve significant power gain, while maintaining Type I error close to the nominal value of 0.05. An empirical application of the methods is demonstrated through a Phase III clinical trial in rare disease.

Mobile Network Coverage Prediction Using Multi-Modal Model Based on Deep Neural Networks and Semantic Segmentation.

A coverage prediction model helps network operators find coverage gaps, plan base station locations, evaluate quality of service, and build radio maps for spectrum sharing, interference management, localization, etc. Existing coverage prediction models rely on the height and transmission power of the base station, or the assistance of a path loss model. All of these increase the complexity of large-scale coverage predictions. In this paper, we propose a multi-modal model, DNN-SS, which combines a DNN (deep neural network) and SS (semantic segmentation) to perform coverage prediction for mobile networks. Firstly, DNN-SS filters the samples with a geospatial-temporal moving average filter algorithm, and then uses a DNN to extract numerical features. Secondly, a pre-trained model is used to perform semantic segmentation of satellite images of the measurement area. Thirdly, a DNN is used to extract features from the results after semantic segmentation to form environmental features. Finally, the prediction model is trained on the dataset consisting of numerical features and environmental features. The experimental results on campus show that for random location prediction, the model achieves a RMSE (Root Mean Square Error) of 1.97 dB and a MAE (Mean Absolute Error) of 1.41 dB, which is an improvement of 10.86% and 10.2%, respectively, compared with existing models. For the prediction of a test area, the RMSE and MAE of the model are 4.32 dB and 3.45 dB, respectively, and the RMSE is only 0.22 dB lower than that of existing models. However, the DNN-SS model does not need the height, transmission power, and antenna gain of the base station, or a path loss model, which makes it more suitable for large-scale coverage prediction.

Impact of a polysidpersed fuel distribution on the ignition characteristic

Determining the thermal profile of ignition is important because the desired ignition behavior varies with the objective. For example, extended ignition prolongs the time that the engine runs; however, fast ignition offers a higher power gain. The pollution caused by undesirable chemical reactions, as determined by the ignition profile, is another important aspect. Based on a previously developed method, we examined the impact of different theoretical particle size distributions (PSDs) on the thermal ignition profile. We compared different PSDs of polydispersed fuel spray with normal distributions with various means, each corresponding to the same fuel volume. Our results revealed a significant dependence of thermal ignition on the PSD. Systems that comprised only low-radius droplets did not reach ignition, whereas systems with only high-radius droplets required a long time to establish ignition. Moreover, the change in the mean droplet radius unexpectedly resulted in a double hump in the maximum temperature of the combustion process.

Thin channel Ga2O3 MOSFET with 55 GHz fMAX and >100 V breakdown

This Letter reports a highly scaled 90 nm gate length β-Ga2O3 (Ga2O3) T-gate MOSFET with a power gain cutoff frequency (fMAX) of 55 GHz. The 60 nm thin epitaxial Ga2O3 channel layer was grown by molecular beam epitaxy, while the highly doped (n++) source/drain regions were regrown using metal organic chemical vapor deposition. Maximum on current (IDS,MAX) of 160 mA/mm and trans-conductance (gm) around 36 mS/mm were measured at VDS = 10 V for LSD = 1.5 μm device. Transconductance and on current are limited by high channel sheet resistance (Rsheet). Gate/drain breakdown voltage of 125 V was measured for LGD = 1.2 μm. We extracted 27 GHz current gain cutoff frequency (fT) and 55 GHz fMAX for 20 V drain bias for unpassivated devices. While no current collapse was seen initially for both drain and gate lag measurements for 500 ns pulse, moderate current collapse was observed after DC, RF measurements caused by electrical stressing. We calculated a high fT. VBR product of 3.375 THz V, which is comparable to the state-of-the-art GaN HEMTs. This figure of merit suggests that Ga2O3 could be a potential candidate for X-band application.

Design and fabrication of S-band power amplifier for wireless sensor networks

This paper discusses the process of designing and manufacturing a wideband power amplifier operating in the S-band. To amplify a low power and broadband radio frequency signals from 2.1 GHz to 2.5 GHz, the proposed power amplifier uses a diagram of a two-stages amplification with peak offset amplification frequency 2.3 GHz. The power amplifier is designed with a center frequency difference of 2.2 GHz and 2.4 GHz respectively to achieve a bandwidth of 400 MHz. The proposed power amplifier (PA) uses RF transistor SHF-0589 using gallium arsenide heterostructure field-effect transistor (GaAs HFET) technology for high gain and low power consumption. The complete amplifier achieves power gain 21.1 dB inband 2.1-2.5 GHz and achieve maximum power gain of 22.5 dB at the frequency of 2.4 GHz; the output power rise up to 33 dBm; input reflection coefficient (S11) reaches -19.2 dB and output reflection coefficient reaches -17.2 dB. The designed amplifier circuit can be used for wireless sensor networks operating at S-band.