High Gain Ratio Research Articles

3-D-Printed Ka-Band Circularly Polarized Monopulse Antenna Array With High Gain and Low Axial Ratio

3-D-Printed Ka-Band Circularly Polarized Monopulse Antenna Array With High Gain and Low Axial Ratio

Omnidirectional circularly polarized base station antenna with high gain and wide band

Omnidirectional circularly polarized base station antenna with high gain and wide band

Design and Simulation of a Cascade Boost DC-DC Converter as a Single-Phase Inverter Power Supply

Currently, the need for new renewable energy is getting higher, so the development of equipment in supporting this is increasingly rapid. designing an inverter that has a high output voltage can be done in several ways, namely by developing from the basic topology of the inverter or developing an inverter input side voltage boost DC-DC converter that has a high gain ratio capability or by using a step up transformer as an AC voltage booster, but it is inefficient considering that the step up transformer has a heavy weight, and reduces space. In this research the researchers designed a cascade boost converter as a single-phase inverter power supply. The cascade boost converter is used as a DC voltage increase where the DC high voltage is entered into a single phase inverter as a DC power supply and the inverter converts from DC-AC. Without using a step up transformer as an AC voltage booster. The inverter is combined with an LC filter as a wave filter to make it close to a sinusoidal wave. The simulation results show that the whole system is able to output a voltage of 220VAC RMS with a frequency of 50Hz.

Algoritma Adaboost pada Metode Decision Tree untuk Klasifikasi Kelulusan Mahasiswa

Colleges provide higher education as the benchmark of education quality and evaluate higher education syllabi. Graduation rates and enrollment capacity are essential for graduation assessment and decision-making. Unfortunately, some students majoring in statistics failed to finish their studies on time, impacting the accreditation of the study program. It is necessary to examine the characteristics of students who managed and failed to complete their studies on time using the data mining classification method, namely Algorithm C5.0. In this study, Adaboost algorithm and Algorithm C5.0 was employed to classify graduation rates accurately. Graduation data of the Statistics Study Program of Universitas Tanjungpura Batch 1 of 20217/2018 to Batch II of 2022/2023 School years were regarded in this study. First, the entropy, gain, and gain ratio values were measured. After that, each data was given equal weight, and iteration was performed 100 times. The analysis using Algorithm C5.0 showed School Accreditation as the variable with the highest gain ratio, indicating that School Accreditation has the most decisive influence on graduation rates with an accuracy percentage of 70%. This percentage then increased to 82.14% after the boosting using the Adaboost algorithm. Adaboost Algorithm is regarded as good in improving the accuracy of algorithm C5.0. The results of this study can provide insight for colleges in designing policies to increase on-time graduation based on the factors that influence student graduation.

Novel Bidirectional Isolated DC/DC Converter with High Gain Ratio and Wide Input Voltage for Electric Vehicle Storage Systems

This study proposes a novel bidirectional isolated DC/DC converter with a high gain ratio and wide input voltage for electric vehicle (EV) storage systems. The DC bus of an EV can be used to charge its battery, and the battery pack can discharge energy to the DC bus through the bidirectional converter when the DC bus lacks power. The input voltage range of the proposed converter is 24 to 58 V on the low-voltage side, which meets the voltage specifications of most servers and batteries on the market. The proposed topology is verified through design, simulation, and implementation, and voltage gain, voltage stress, and current stress are investigated. The control bidirectional converter is simple. Only one set of complementary signals is required for step-up and step-down modes, which greatly reduces costs. The converter also features a continuous current at the low-voltage side, a leakage inductance function for energy recovery, and zero-voltage switching (ZVS) on certain switches, which can prevent voltage spikes on the switches and increase the efficiency of the proposed converter. A bidirectional converter with a total power of 1 kW is used to verify the topology’s feasibility and practicability. The power at the low-voltage side was 24–58 V, and the maximum efficiency in step-up mode was 94.5%, 96.5%, and 94.8%, respectively; the maximum efficiency in step-down mode was 94.4%, 95.4%, and 93.7%, respectively.

A new design of wide blade ultrasonic horns using Non-Uniform Rational B-Spline shaped slots

In the present study, for the first time, the shapes of slots of wide blade horns are optimized using Non-Uniform Rational B-Spline (NURBS) curves. Here, two 20 kHz horns with different gain ratios (2.5 and 3.5) are designed. The amplitude uniformity and maximum stress of horns are regarded to design. Some control points are used to define the shape of slots, and the position and weight of these points are determined. The genetic algorithm with a link to Abaqus is applied for the optimization process. The simulation results show that the designed horns have high amplitude uniformity equal to 0.978, 0.965. Also, the maximum stresses are 73.08 MPa and 78.52 MPa, which are less than the fatigue strength with a safety factor of 2. It is found that the stress values in the bottom of NURBS-shaped slots are considerably lower than the simple slots, making it possible to design the horns with a higher gain ratio without fatigue failure. Finally, the performance of the present design is verified by doing some experiments on the fabricated horn, which confirms that the proposed design can be successfully utilized as a new method to design wide blade horns.

A Compact Flexible Circularly Polarized Implantable Antenna for燘iotelemetry Applications

With the help of in-body antennas, the wireless communication among the implantable medical devices (IMDs) and exterior monitoring equipment, the telemetry system has brought us many benefits. Thus, a very thin-profile circularly polarized (CP) in-body antenna, functioning in ISM band at 2.45 GHz, is proposed. A tapered coplanar waveguide (CPW) method is used to excite the antenna. The radiator contains a pentagonal shape with five horizontal slits inside to obtain a circular polarization behavior. A bendable Roger Duroid RT5880 material (εr = 2.2, tanδ = 0.0009) with a typical 0.25 mm-thickness is used as a substrate. The proposed antenna has a total volume of 21 × 13 × 0.25 mm3. The antenna covers up a bandwidth of 2.38 to 2.53 GHz (150 MHz) in vacuum, while in skin tissue it covers 1.56 to 2.72 GHz (1.16 GHz) and in the muscle tissue covers 2.16 to 3.17 GHz (1.01 GHz). GHz). The flexion analysis in the x and y axes was also performed in simulation as the proposed antenna works with a wider bandwidth in the skin and muscle tissue. The simulation and the curved antenna measurements turned out to be in good agreement. The impedance bandwidth of −10 dB and the axis ratio bandwidth of 3 dB (AR) are measured on the skin and imitative gel of the pig at 27.78% and 35.5%, 13.5% and 4.9%, respectively, at a frequency of 2.45 GHz. The simulations revealed that the specific absorption rate (SAR) in the skin is 0.634 and 0.914 W/kg in muscle on 1g-tissue. The recommended SAR values are below the limits set by the federal communications commission (FCC). Finally, the proposed low-profile implantable antenna has achieved very compact size, flexibility, lower SAR values, high gain, higher impedance and axis ratio bandwidths in the skin and muscle tissues of the human body. This antenna is smaller in size and a good applicant for application in medical implants.

Low Noise Balanced Homodyne Detector for Quantum Noise Measurement

The research of quantum noise in the interaction of laser and atoms plays a critical role in quantum optical experiments. The measurement of quantum noise is mainly based on the balanced homodyne detection method. Here, we reported a balanced homodyne detector with low noise, high gain, and high common-mode rejection ratio (CMRR) at the wavelength of 795 nm. By optimizing the selection of components and printed circuit board (PCB) layout, a minimum electronic noise of &#x2212;96.7 dBm is obtained. Over the range of 1 MHz to 5 MHz, we get a flat CMRR above 59 dB and a linear gain regime, which can enable a shot noise measurement with the laser power of <inline-formula> <tex-math notation="LaTeX">$100~\mu \text{w}$ </tex-math></inline-formula>. The developed detector can be used in quantum coherent experiments with a weak probe laser of power down to tens of microwatts.

Ivabradine increases the high frequency gain ratio in the vagal heart rate transfer function via an interaction with muscarinic potassium channels.

Muscarinic potassium channels (I K,ACh) are thought to contribute to the high frequency (HF) dynamic heart rate (HR) response to vagal nerve stimulation (VNS) because they act faster than the pathway mediated by hyperpolarization‐activated cyclic nucleotide‐gated (HCN) channels. However, the interactions between the two pathways have not yet been fully elucidated. We previously demonstrated that HCN channel blockade by ivabradine (IVA) increased the HF gain ratio of the transfer function from VNS to HR. To test the hypothesis that IVA increases the HF gain ratio via an interaction with I K,ACh, we examined the dynamic HR response to VNS under conditions of control (CNT), I K,ACh blockade by tertiapin‐Q (TQ, 50 nM/kg), and TQ plus IVA (2 mg/kg) (TQ + IVA) in anesthetized rats (n = 8). In each condition, the right vagal nerve was stimulated for 10 min with binary white noise signals between 0–10, 0–20, and 0–40 Hz. On multiple regression analysis, the HF gain ratio positively correlated with the VNS rate with a coefficient of 1.691 ± 0.151 (×0.01) (p < 0.001). TQ had a negative effect on the HF gain ratio with a coefficient of −1.170 ± 0.214 (×0.01) (p < 0.001). IVA did not significantly increase the HF gain ratio in the presence of TQ. The HF gain ratio remained low under the TQ + IVA condition compared to controls. These results affirm that the IVA‐induced increase in the HF gain ratio is dependent on the untethering of the hyperpolarizing effect of I K,ACh.

Structural and spectroscopic investigations of neodymium-doped strontium borophosphate glass.

Neodymium-doped glass finds application in lasers with high energy and low pulse width. In the present study, a series of Nd3+ ions (0-2 mol%)-doped strontium borophosphate (SBP) glass samples was prepared through the conventional melt quench method. A broad peak in the X-ray diffraction spectrum confirmed the formation of a single-phase amorphous borophosphate glass. Fourier transform infrared spectra of the doped and undoped glass samples indicated the presence of borate and phosphate groups that form the anionic network. The thermal properties of the glass samples were determined from thermogravimetry/differential thermal analysis. Photoluminescence and ultraviolet-visible light techniques were used to investigate the optical properties of the as-prepared SBP:Nd glass. The Judd-Ofelt (JO) intensity parameters Ωλ (2, 4, 6), stimulated emission cross-section, branching ratios, and transition probabilities of the Nd3+ -doped glass were obtained through the JO analysis. Characteristic Nd3+ emission peaks were observed at 1330, 1060, and 876 nm, corresponding to the 4 F3/2 →4 IS/2 (S = 13, 11, and 9) transitions, respectively. The suitability of SBP:Nd (0.5 mol%) glass for use in solid-state lasers was demonstrated by its intense luminescence, high transition probability, high emission cross-section, optical gain, and luminescence branching ratio.

Gray water treatment by air-gap multi-effect membrane distillation with pre-treatment by electrocoagulation

Abstract The gap between supply and demand of fresh water is widening due to increase in global population. Hence, an alternative source of water such as gray water could potentially save a significant amount of precious fresh water. Gray water is distinct from black water by the amount and composition of its chemical and biological contaminants. In this paper, an air-gap Multi-effect membrane distillation (MEMD) module performance for gray water treatment is described. Surfactant present in the gray water was wetting the membrane pores. Hence, electrocoagulation was used as a pre-treatment of gray water feed. About 99.14% surfactants were removed by electrocoagulation and the experiment shows excellent performance of the MEMD module. The 4-stage MEMD module offered permeate fluxes nearly to 50.12 l/m2 h at 80 °C. It was also found that a high thermal efficiency and output gain ratio was possible with lower specific energy and no cooling water. Hence, it is apparent that the air gap MEMD technology could be used for gray water treatment. Pre-treatment by electrocoagulation (EC) operation seems an important step in the overall treatment process when large amounts of surfactants are present in the treatment water.

Design of Low-Power Low-noise CMOS ECG Amplifier for Smart Wearable Device

The artificial intelligence health care devices have focused on the portability and accuracy and the most trending area of wearable biomedical application has become the electrocardiogram (ECG) recording device. The ECG signals have the characteristic of low amplitude, prone to be influenced by Power Line Interference (PLI), so it is essential to achieve high gain and high common-mode rejection ratio (CMRR),while the input-referred noise and power consumption need to be low to realize the cardiac screening system on chip (Soc).In this paper, a low-noise low-power analog front end (AFE) amplifier which based on Driven-Right-Leg circuit(DRL) has been proposed. It was implemented in CMOS 180 nm with bias current and supply voltage of 12µA and 0.7V, respectively. The simulation results showed that this front-end circuit can achieve a low input referred noise of 4.11µV/Hz and high common mode rejection ratio of 135dB. It also gave voltage gain of 41.8 dB with the bandwidth from 0.1Hz to 100Hz and the total power consumption was 4.32µW. Compared with recently relevant whole circuit design, we believe that it is suitable to be used in smart wearable device.

IMPLEMENTATION AND SIMULATION ANALYSIS OF MODIFIED SEPIC CONVERTER FOR RENEWABLE ENERGY APPLICATION

Regularization in power production increasing global need of power the renewable energy resource brings more attention. These resources are responsible for deducing carbon dioxide emission during burning coal, deforestation due to extension and installation of hydroelectric power plants, ozone layer depletion. Among hydro, tidal, wind, solar, geothermal; solar is preferred due to affordability and availability, compact in structure. The structure of Single ended primary inductor converter (SEPIC) interfaced with renewable energy resource to obtain high voltage gain is proposed in this paper. The SEPIC converter has several benefits such as low voltage distortion, reduction in noise level, low switching stress, and continuous input current. Also, high voltage gain and input current continuity make the presented converter suitable for renewable energy sources. The modified structure provides high gain ratio with a single power semiconducting switch. With less number of active and passive components enrolled within proposed system deduce capital cost and improves efficiency. The system efficiency is also analyzed with voltage gain under continuous and discontinuous conduction mode. Depending upon the reactive component’s voltage-current ratio of active and passive components is chosen respectively. The circuit topology is verified is through MATLAB software and experimental analysis.

High Step-Up DC–DC Converter With Efficient Inductive Utilization

This article offers a new high step-up dc-dc converter based on a coupled inductor. The proposed single-switch converter employs different inductive and capacitive techniques to transfer the input power to the output load in operational modes. It reaches to high output voltage gains in lower duty cycles, which results in lower switch loss for a specific voltage gain. Two output ports are utilized to share the overall output voltage, reduce the voltage stress of each port components and decrease the total output voltage ripple in high voltage gain ratios. Continuous input current, recycling the stored energy of magnetizing and leakages inductances, alleviating the switch voltage spikes, no circulating current, low input current ripple, high power density, wide output voltage range and simple pulse width modulation with a vast control area are the other features of the proposed converter. In this article, the proposed converter is analyzed in the steady-state operation of continuous and discontinuous conduction modes, and comprehensive comparisons are performed to evaluate its capabilities. Moreover, power loss calculations and design procedure are followed with experimental results to verify theoretical analytics.

Europium luminescence in silver and gold nanoparticles co-embedded phosphate glasses: Judd-Ofelt calculation

Some europium ions (Eu3+) activated magnesium-zinc-sulfophosphate glasses with the silver (Ag) and gold (Au) nanoparticles (NPs) co-embedment were prepared via the melt-quenching method. The as-prepared samples were characterised using different analytical techniques to determine the effect of various Au NPs contents (0.05, 0.10, 0.15, 0.20, 0.25, and 0.30 g) on their spectroscopic characteristics. Furthermore, the Judd-Ofelt theory was used to evaluate the intensity parameters and radiative properties of the glasses. These glasses showed very high optical gain (in the range of 5.10 × 10−25 to 15.87 × 10−25 cm2 s−1) and branching ratio (from 8.27 to 61.6%). The glass prepared with Au NPs of 0.25 g revealed the highest optical gain (15.7 × 10−25 cm2 s−1) and gain bandwidth (9.55 × 10−22 cm2) for the 5D0→7F2 transition. The observed significant increase in the stimulated emission cross-section of the glasses indicated their prospect towards the photonic device fabrication. The achieved improvement in the photoluminescence emission intensity for the 5D0→7F2 transition was largely credited to the energy transfer between the Eu3+ and NPs inside the glasses. The high colour purity (for red colour coordinate) of the glasses obtained from the CIE chromaticity diagram suggested their potential for the development of efficient red laser.

Performance Analysis of Modified High Voltage Gain Boost Converter for PV-fed LED Lighting Applications

Nowadays, the development of PV (Photo Voltaic)-fed LED (Light Emitting Diode) lighting technology is requires high gain ratios with efficient performance of the converter. The presented converter topology is non-isolated possess high gain voltage with low stress voltage. The design of the modified high voltage gain boost configuration is projected with continuous current at input, which is flexible to control. The conduction, switching loss at the switch, reverse recovery problem and electromagnetic interference are mitigated due to low duty cycle. But to explore the differentiation of their characteristics, advantages and several reasonable evaluations are carried out. The operating principle, theoretical analysis and experimental results of modified high gain step-up converter are provided for PV-fed LED lighting applications to verify the efficient performance in all aspects.

Metallic Monopole Parasitic Antenna With Circularly Polarized Conical Patterns

In this paper, a new geometry for antenna producing conical patterns with circular polarization is proposed. The symmetrically placed parasitic posts, with different horizontal and vertical segments, around the centrally fed monopole control the circular polarization purity and the angle of maximum gain. The 3-D geometry favors high gain at low elevation angles. A circular ground plane atop a choke ring facilitates easy mounting of a radome and improves gain at lower elevation due to lower backlobe. The all-metal radiator has good mechanical stability and remains impervious to large temperature variations, which is ideal for use in space applications. An application to a Martian transponder at the $X$ -band is also discussed. The measured results of the manufactured antennas show a good agreement with those of the simulated one. Furthermore, the optimization of the antenna design parameters allows the antenna to have high gain and low axial ratio (AR), from high elevation ( $\theta _{max}=35^{\circ }$ ) to low elevation ( $\theta _{max}=70^{\circ }$ ) angles.

Determination of the Criteria for Comparative Analysis of Desalination Plant

The problem of fresh water lack can be solved my desalination of the seawater. Desalination of the seawater can be accomplished by several methods. Distillation of the seawater is one of the most promising among them. Comparative analysis of distillation desalination plant requires certain criteria. This criterion must take into account both energy consumption and seawater salinity. Relation of the minimal work required for seawater desalination to energy consumption was selected as such criterion. Four types of the distillation plants were considered: Multi-effect distillation plants (MED), multi-effect distillation plants with mechanical vapor compression (MVC) plants, MVC desalination plants have the best multi-effect distillation plant with thermal vapor compression (TVC) plants and Multistage flash distillation plants (MSF). MSF plants gave dependency that their efficiency rise along the gain ratio. That may be explained by the fact that its steam consumption does not depend on seawater consumption. TVC plants have slightly higher efficiency than MED plants. Thus, MVC plants can be recommended to use if there is no heat source, MSF plants - if there is heat source and plant must have a high gain ratio and TVC plant in the rest cases.

High Voltage Gain Ratio Isolated Resonant Switched-Capacitor Converter for Sustainable Energy

A novel high-gain isolated two-switch boosting resonant switched-capacitor (ITBRSC) converter for sustainable energy is presented in this paper. It concludes a two-switch boosting resonant switched-capacitor (TBRSC) converter unit, an isolated transformer unit, and a load voltage regulation unit. There are two small value inductors in the proposed topology. They are, respectively, injected into the charge loop and the discharge loop. As a result, the pulsating input current is highly decreased. In this way, it could achieve the continuous input current in the primary side of ITBRSC converter. The TBRSC converter unit boosts the input voltage with the high gain ratio. In combination with the transformer, the ITBRSC converter could provide a good isolation performance by adopting the transformer. The proposed converter in this paper could be used in the variable input voltage and wide operation area. It could be acted as the high-gain isolated power supply for sustainable energy systems, such as electric vehicles and wind energy. The SC converter-based high-gain isolated converter could achieve the high power density and simple topology. A 500-W power-rating ITBRSC converter is constructed. The function of the ITBRSC converter is demonstrated and tested with the simulation and experiments. The high gain ratio and robust performance of the proposed converter are totally verified. It could facilitate the application of SC converters for sustainable energy.

Dual-Switch Boost DC–DC Converter for Use in Fuel-Cell-Powered Vehicles

To facilitate voltage matching between the cell stack and power batteries in fuel-cell-powered vehicles, an implementation of a simple dual-switch boost DC–DC converter topology has been proposed in this paper. Compared with existing boost topologies, the one proposed herein reduces the number of components required and stress induced whilst maintaining a high-gain ratio. The results of experiments performed in this paper reveal that the corresponding to a duty ratio of 0.8, the proposed converter topology demonstrates the realization of a boost ratio of 6, thereby exceeding that the realized by conventional boost converters by nearly 73%. In addition, at an output voltage of 50 V, a maximum operating efficiency of 91% was achieved. These results demonstrate the effectiveness and feasibility of the proposed DC–DC converter topology for use in fuel-cell-powered vehicles.