Sufficient Output Power Research Articles

A Molecular Adsorption Concept for Increasing Energy Density of Hybrid Supercapacitors.

In this report, we demonstrate that high-capacity hybrid supercapacitors can be realized by utilizing iron azaphthalocyanine (FeAzPc-4N) adsorbed activated carbons (ACs) as an electrode due to the combination of the electric double layer of activated carbon surfaces and redox reactions of FeAzPc-4N molecules. By increasing the mixing ratio of FeAzPc-4N with ACs, a maximum capacity of 907 F/gAC is achieved, also enabling rapid charging and discharging at 20 A/g. The revelation of the capacitor electrode's durability through 20 000 cycles of charging and discharging is realized, and the capacitor cell had sufficient output power to illuminate LEDs. This concept illustrates the potential for enhancing capacitor performance by immobilizing redox-active species.

Biomimetic Ultrasonic Vibrator with Broadband Characteristics Inspired by Leaf-Cutting Ants.

Power ultrasound is widely used in industrial production, medical equipment, aerospace, and other fields. Currently, there are two main types of commonly used power generation devices: piezoelectric ultrasonic transducers and magnetostrictive ultrasonic transducers. However, in certain situations with limited external dimensions, the applications of existing power ultrasound devices are limited. In nature, leaf-cutting ants excite vibrations through their tiny organs. Inspired by the vibratory organs of leaf-cutting ants, a new type of biomimetic ultrasonic vibrator (BUV) comprising a scraper, dentate disc, and fixture system was proposed, fabricated, and tested in this study. The experimental results showed that the BUV could operate in the frequency range of 16.8-19 kHz. Within the working frequency range, the vibration of the BUV was stable and the amplitude of the vibration displacement was greater than 22 µm. The operating frequency band of the BUV was broader than those of the piezoelectric and magnetostrictive ultrasonic transducers. In addition, the BUV can cut soft rubber and pig tissues with sufficient output power and load-carrying capacity. The BUV, as a new type of power ultrasonic excitation device, is expected to be applied in high-power micro operating scenarios, such as minimally invasive surgical instruments.

Highly Stretchable, Knittable, Wearable Fiberform Hydrovoltaic Generators Driven by Water Transpiration for Portable Self-Power Supply and Self-Powered Strain Sensor.

The development of excellently stretchable, highly mobile, and sustainable power supplies is of great importance for self-power wearable electronics. Transpiration-driven hydrovoltaic power generator (HPG) has been demonstrated to be a promising energy harvesting strategy with the advantages of negative heat and zero-carbon emissions. Herein, this work demonstrates a fiber-based stretchable HPG with the advantages of high output, portability, knittability, and sustainable power generation. Based on the functionalized micro-nano water diffusion channels constructed by the discarded mask straps (MSs) and oxidation-treated carbon nanomaterials, the applied water can continuously produce electricity during the spontaneous flow and diffusion. Experimentally, when a tiny 0.1mL of water encounters one end of the proposed HPG, the centimeter-length device can yield a peak voltage of 0.43V, peak current of 29.5µA, and energy density of 5.833mWhcm-3. By efficiently integrating multiple power generation units, sufficient output power can be provided to drive commercial electronic devices even in the stretched state. Furthermore, due to the reversibility of the electrical output during dynamic stretching-releasing, it can passively convert physiological activities and motion behaviors into quantifiable and processable current signals, opening up HPG's application in the field of self-powered wearable sensing.

Intra-Articular Ultrasonography Probe for Minimally Invasive Upper Extremity Arthroscopic Surgery: A Phantom Study.

Upper extremity arthroscopic surgery is a highly technique-dependent procedure that requires the surgeon to assess difficult cartilage conditions and manage the risk of iatrogenic damage to nerves and vessels adjacent to the joint capsule in a confined joint space, and a device that can safely assist in this procedure has been in demand. In this study, we developed a small intra-articular ultrasound (AUS) probe for upper extremity joint surgery, evaluated its safety using underwater sound field measurement, and tested its visualization with a phantom in which nerves and blood vessels were embedded. Sound field measurement experiments confirmed the biological safety of the AUS probe's output, while confirming that sufficient output power level performance was obtained as an ultrasound measurement probe. In addition, images of blood vessels and nerves were reconstructed discriminatively using A-mode imaging of the agar phantom. This study provides proof-of-concept of the AUS probe in upper extremity surgery. Further studies are needed to obtain approval for use in future medical devices.

Ultralow-Power Photoplethysmography (PPG) Sensors: A Methodological Review

PPG sensors are used to accurately, instantaneously, and non-invasively measure vital signs to provide a real-time indication of overall physical health and long-term well-being. Achieving long-term continuous monitoring is an important requirement to increase user safety and diagnostic accuracy. PPG sensors need a light-emitting diode (LED) with sufficient output power to detect the PPG signal, which consumes tens of mW. On the other hand, low AC/DC ratios of <0.1-4%, ambient light, motion artifacts, and semiconductor noise greatly affect the signal-to-noise ratio (SNR), dynamic range (DR), and signal quality. Specialized circuit blocks are needed to cancel these interferences, further increasing power consumption. Several ultra-low-power designs, circuit techniques, and sampling schemes have been proposed in the literature to extend PPG sensors’ lifetime. This paper reviews, analyzes, and critiques these solutions to provide designers with comprehensive design considerations for achieving ultra-low power consumption while achieving the required SNR and DR in a PPG sensor design.

Broadband Vibration-Based Energy Harvesting for Wireless Sensor Applications Using Frequency Upconversion.

Silicon-based kinetic energy converters employing variable capacitors, also known as electrostatic vibration energy harvesters, hold promise as power sources for Internet of Things devices. However, for most wireless applications, such as wearable technology or environmental and structural monitoring, the ambient vibration is often at relatively low frequencies (1-100 Hz). Since the power output of electrostatic harvesters is positively correlated to the frequency of capacitance oscillation, typical electrostatic energy harvesters, designed to match the natural frequency of ambient vibrations, do not produce sufficient power output. Moreover, energy conversion is limited to a narrow range of input frequencies. To address these shortcomings, an impacted-based electrostatic energy harvester is explored experimentally. The impact refers to electrode collision and it triggers frequency upconversion, namely a secondary high-frequency free oscillation of the electrodes overlapping with primary device oscillation tuned to input vibration frequency. The main purpose of high-frequency oscillation is to enable additional energy conversion cycles since this will increase the energy output. The devices investigated were fabricated using a commercial microfabrication foundry process and were experimentally studied. These devices exhibit non-uniform cross-section electrodes and a springless mass. The non-uniform width electrodes were used to prevent pull-in following electrode collision. Springless masses from different materials and sizes, such as 0.5 mm diameter Tungsten carbide, 0.8 mm diameter Tungsten carbide, zirconium dioxide, and silicon nitride, were added in an attempt to force collisions over a range of applied frequencies that would not otherwise result in collisions. The results show that the system operates over a relatively wide frequency range (up to 700 Hz frequency range), with the lower limit far below the natural frequency of the device. The addition of the springless mass successfully increased the device bandwidth. For example, at a low peak-to-peak vibration acceleration of 0.5 g (peak-to-peak), the addition of a zirconium dioxide ball doubled the device's bandwidth. Testing with different balls indicates that the different sizes and material properties have different effects on the device's performance, altering its mechanical and electrical damping.

Advanced Cellulose-Nanocarbon Composite Films for High-Performance Triboelectric and Piezoelectric Nanogenerators.

Natural polymers such as cellulose have interesting tribo- and piezoelectric properties for paper-based energy harvesters, but their low performance in providing sufficient output power is still an impediment to a wider deployment for IoT and other low-power applications. In this study, different types of celluloses were combined with nanosized carbon fillers to investigate their effect on the enhancement of the electrical properties in the final nanogenerator devices. Cellulose pulp (CP), microcrystalline cellulose (MCC) and cellulose nanofibers (CNFs) were blended with carbon black (CB), carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs). The microstructure of the nanocomposite films was characterized by scanning electron and probe microscopies, and the electrical properties were measured macroscopically and at the local scale by piezoresponse force microscopy. The highest generated output voltage in triboelectric mode was obtained from MCC films with CNTs and CB, while the highest piezoelectric voltage was produced in CNF-CNT films. The obtained electrical responses were discussed in relation to the material properties. Analysis of the microscopic response shows that pulp has a higher local piezoelectric d33 coefficient (145 pC/N) than CNF (14 pC/N), while the macroscopic response is greatly influenced by the excitation mode and the effective orientation of the crystals relative to the mechanical stress. The increased electricity produced from cellulose nanocomposites may lead to more efficient and biodegradable nanogenerators.

Interband cascade technology for energy-efficient mid-infrared free-space communication

Space-to-ground high-speed transmission is of utmost importance for the development of a worldwide broadband network. Mid-infrared wavelengths offer numerous advantages for building such a system, spanning from low atmospheric attenuation to eye-safe operation and resistance to inclement weather conditions. We demonstrate a full interband cascade system for high-speed transmission around a wavelength of 4.18 µm. The low-power consumption of both the laser and the detector in combination with a large modulation bandwidth and sufficient output power makes this technology ideal for a free-space optical communication application. Our proof-of-concept experiment employs a radio-frequency optimized Fabry–Perot interband cascade laser and an interband cascade infrared photodetector based on a type-II InAs/GaSb superlattice. The bandwidth of the system is evaluated to be around 1.5 GHz. It allows us to achieve data rates of 12 Gbit/s with an on–off keying scheme and 14 Gbit/s with a 4-level pulse amplitude modulation scheme. The quality of the transmission is enhanced by conventional pre- and post-processing in order to be compatible with standard error-code correction.

High-Power LiNbO3 Domain-Wall Nanodevices.

Wide band gap semiconductors keep on pushing the limits of power electronic devices to higher switching speeds and higher operating temperatures, including diodes and transistors on low-cost Si substrates. Alternatively, erasable conducting walls created within ferroelectric single-crystal films integrated on the Si platform have emerged as a promising gateway to adaptive nanoelectronics in sufficient output power, where the repetitive creation of highly charged domain walls (DWs) is particularly important to increase the wall current density. Here, we observe large conduction of the head-to-head DW at an optimized inclination angle of 15° within a LiNbO3 single crystal that is 3-4 orders of magnitude higher than that of the tail-to-tail DW. The wall conduction is diode-like with a linear current density of higher than 1 mA/μm and an on/off ratio of larger than 106 under the application of a repetitive switching voltage pulse in time less than 10 ns and an endurance number of higher than 105. The high-power diodes can not only perform direct data processing in high-density nonvolatile DW memories in fast operation speeds and low-energy consumption but also function as sensors in compact electromechanical systems, selectors in phase-change memory and resistive random-access memory, and half-wave/full-wave rectifiers in modern nanocircuits in dimensions approaching the thickness of the depletion layer below which the tradition p-n junction malfunctions.

A Wideband Balanced Amplifier Using Edge-Coupled Quadrature Couplers in 0.13-μm SiGe HBT Technology

In this work, a wideband millimeter-wave (mm-wave) power amplifier (PA) is reported. To provide excellent input/output impedance matching across broadband, sufficient output power and high power-added efficiency (PAE), a balanced amplifier (BA)-based architecture is used in designing this PA. In particular, an edge-coupled quadrature coupler is designed as its RF-power-division/combination block, and its performance in terms of magnitude/phase balance error is minimized throughout a relatively wide bandwidth. A PA prototype is fabricated in 0.13- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> SiGe HBT technology and tested. Under a 1.6-V power supply, the variation of small-signal gain is less than 3 dB within 20-40 GHz, which is equivalent to more than 66% fractional 3-dB bandwidth. Within this frequency range, at least 15.8 dBm saturated output power could be delivered with the peak PAE higher than 16.8%. The designed PA supports a single-carrier 200-MHz 64-quadrature amplitude modulation (QAM) with higher than 12.8-dBm average output power, while still maintaining an error vector magnitude (EVM) below −25 dB at 30 GHz. The size of the designed compact-size PA, including all pads, is only 0.7 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times1.3$ </tex-math></inline-formula> mm.

High-Output-Power 1358-nm-Wavelength SOA-Integrated EADFB Laser (AXEL) for 25-Gbit/s 100-km Transmissions

We developed a 1358-nm-wavelength semiconductor optical amplifier (SOA)-assisted extended-reach electroabsorption modulator integrated distributed feedback laser (AXEL) as a high-power light source for 25G-class passive optical networks (PONs) to ensure sufficient power margin in the transmitter and extend the transmission reach to 100 km. We investigated the effect of the integrated SOA length on the light output power and modulation performance of the AXEL. We found that there was no significant degradation in modulation performance at 25 Gbit/s even for an AXEL with a 175-μm-long SOA. Using this AXEL chip, we fabricated a transmitter by using a commercially available package. The transmitter attained sufficient modulated light output power of 10. 5 dBm and had a high-quality eye diagram for 25-Gbit/s operation. In addition, we found that the measured chirp parameter of the AXEL transmitter was almost 0. This alleviates the transmission distance limitation due to chromatic dispersion and enables the transmission distance to be extended. The loss budget for 20-km transmission, as determined from the measured bit error rate, was 38.4 dB, which is much larger than the value specified for 25G-EPONs. Moreover, the transmission reach was extended to 100 km for the first time, thanks to the AXEL transmitter's high output power. Finally, the possibility of incorporating the AXEL in 100-Gbit/s-ZR4 (80 km) applications using four wavelength channels was considered. The estimated power penalties using the measured chirp parameter were significantly smaller than the measured penalty for 1358 nm. This suggests that the AXEL can also be used for 100-Gbit/s over 80-km transmissions using four channels in a LAN-WDM grid.

Formation and Properties of Thermistor Chips Based on Semiconductor 3D Metal Oxide Films Obtained by RF-Magnetron Sputtering

The formation of oxide semiconductor films of the (Mn,Co,Cu)3O4 type by radio frequency magnetron sputtering is presented. The conditions of deposition and subsequent heat treatment make it possible to obtain films with electrophysical characteristics close to those of the bulk ceramic materials used as a target for magnetron sputtering. Two variants of thermistor geometry were implemented. In the first case, the working layer of oxide semiconductor was deposited directly on the dielectric substrate (planar geometry), and in the second case on the layer with high electrical conductivity (Ni or Al) forming the inner electrode (layered geometry). The lower limit of the nominal resistance of the planar thermistor while maintaining high temperature nonlinearity is ~ 10 kΩ. The layered structure with the inner electrode makes it possible to reduce the lower limit of resistance up to ~ 50 Ω without losing the temperature nonlinearity of the thermistor. In addition, heat treatment above 450 °C or current self-heating with sufficient power output leads to the appearance of a pronounced voltage nonlinearity, which increases the thermal constant B of thermistors from 2400-3400 to 5000-5500 K. The fields of application of oxide-film structures for the correction of linear resistors and the implementation of integration approaches in the construction of linearized sensors are discussed.

Mechanical and electrical properties of Na0.55K0.45NbO3 + 0.2% MnO/Al2O3 composites for energy harvesting applications

To increase the power output of piezoelectric energy harvesters, there are several options that have been the focus in a number of scientific studies. This work explores a new concept, by using ceramic/ceramic composites (Na0.55K0.45NbO3 + 0.2% MnO/Al2O3) for energy harvesting applications. The idea of increasing the elastic properties to maintain a sufficient power output is used. Mechanical and electrical properties of these composites with varying Al2O3 content have been evaluated to determine the energy harvesting properties. Here, the measured power densities exceeded the predicted values with a decrease from 0.11 μW mm−3 at 0 vol% to approximately 0.09 μW mm−3 between 5 and 15 vol%. Observations on the dielectric, piezoelectric and elastic properties revealed a residual stress inside the piezoelectric matrix. Whereas residual stress had a negative effect on the piezoelectric properties due to domain clamping and direct measurements of the energy harvesting properties showed a positive enhancement.

All-polymer indoor photovoltaic modules

SummaryIndoor photovoltaic (IPV) with power output over 100 μW is promising to power the numerous sensor nodes in the Internet of Things (IoT) ecosystem. All polymer photovoltaic has the advantages of excellent thermal stability and superior mechanical properties. In this work, we fabricate the first all-polymer indoor photovoltaic module with the active area of 10 cm2. The module uses polymer donor CD1 and new polymer acceptor PBN-21 with medium optical band gap of 1.9 eV as the active layer. It is processed with eco-friendly solvent tetrahydrofuran and the morphology can be improved by blade coating at 55°C. Under light emitting diode illumination at 1000 lux, the module exhibits a power conversion efficiency of 12.04% and a power output of 367.2 μW. The sufficient power output, high efficiency, excellent stability, and eco-friendly processing indicate that all-polymer indoor photovoltaic is a promising approach to achieve the self-powered of sensor nodes in the IoT ecosystem.

A Sustainable and Flexible Microbrush-Faced Triboelectric Generator for Portable/Wearable Applications.

Triboelectric nanogenerators (TENGs) are put forward as a state-of-the-art energy-scavenging technology for self-powered electronics, but their severe wear and degradation driven by inevitable friction can pose significant durability and sustainability concerns. Here, an array of microfibers is reported that functions as a robust and sustainable TENG in both in-plane sliding and vertical contact-separation modes, with excellent electrical potential as high as 20V and a high cyclability of 3000. The design flexibility of this microbrush TENG (MB-TENG) on the counter materials facilitates the further improvement of electrical outputs, benefiting numerous applications of human-interactive triboelectrification. Significantly, these MB-TENGs offer sufficient output power for successfully driving a smartwatch as well as an electromyography module. This technology uses a simple and cost-effective manner to provide a robust and reliable monolithic TENG module, which is expected to serve as a promising energy-harvesting source for self-powered electronics in the near future.

All-Polymer Indoor Photovoltaic Modules

Indoor photovoltaic (IPV) with power output over 100 μW is promising to power the numerous sensor nodes in Internet of Things (IoT) ecosystem. All polymer photovoltaic has the advantages of excellent thermal stability and superior mechanical property. In this work, we fabricate the first all-polymer indoor photovoltaic module with the active area of 10 cm2. The module uses polymer doner CD1 and new polymer acceptor PBN21 with medium optical bandgap of 1.9 eV as the active layer. It is processed with ecofriendly solvent tetrahydrofuran and the morphology can be improved by blade coating at 55 oC. Under light emitting diode illumination at 1000 lux, the module exhibits a power conversion efficiency of 12.04% and a power output of 367.2 μW. The sufficient power output, high efficiency, excellent stability and eco-friendly processing indicate that allpolymer indoor photovoltaic is a promising approach to achieve the self-powered of sensor nodes in IoT ecosystem.

Bendable Microwave AlGaN/GaN High-Electron-Mobility Transistor With Output Power Density of 2.65 W/mm

Flexible radio frequency (RF) devices are in high demand for wearable electronics; however, they currently do not offer sufficient output power for application in fifth-generation wireless communication systems. This paper reports a bendable gallium nitride (GaN) high-electron-mobility-transistor (HEMT) with state-of-the-art output power in the microwave band. In this study, a fabrication method is proposed, where HEMT is originally grown on silicon carbide (SiC) substrates. After thinning the SiC substrates down to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu \text{m}$ </tex-math></inline-formula> , HEMT is transferred using a copper film rather than flexible substrates used in other studies. The measurements indicated that the fabricated devices exhibited a saturation output power of 2.65 W, corresponding to a power density of 2.65 W/mm, which was associated with maximum power added efficiency (PAE) of 51% at 3 GHz. The performance of the fabricated device remained stable even with a bending radius of up to 0.6 cm. These results indicated that the proposed fabrication method can potentially be used to realize high-power flexible RF electronics.

WITHDRAWN: Smart bi-facial solar inverter with effective charging system

Abstract Generating and sustaining energy is an essential part of the modern technological age. The role of the solar in creating energy is very important one. This paper mainly represents the effective utilization of solar power and reducing power consumption for house hold appliances. A Solar bi-facing panel, an effective charging system and power consumption algorithm are the requirements for accomplishing this task. Mainly we can monitor the power consumption and its reductions using IoT module through mobile. The main advantage in this method is whenever sufficient output power received from Solar panel that will be used for maximum charging of the battery. The effective charging system which was controlled by microcontroller, increases the life time of the battery is an added advantage. Controller, updates the analysed data frequently to IoT cloud through IoT gateway.

Optimal Range of Coupling Coefficient of Loosely Coupled Transformer Considering System Resistance

Accurate system resistance may lead to an obvious error between the simulated and the real efficiency of the system. This paper proposes an optimal range of coupling coefficient for ensuring the efficiency and the sufficient output power of the WPT (wireless power transfer) system. A 3-kW prototype WPT system is manufactured and the effectiveness of the optimal range of coupling coefficient is validated.

Mid-Range Wireless Power Transfer System for Various Types of Multiple Receivers Using Power Customized Resonator

This paper presents a high-efficiency wireless power transfer (WPT) system that can charge multiple receivers (Rx's) of various types. For system analysis, the transmitted power and received power levels are derived using the parameters of the resonators based on electro-magnetic (EM) resonance. Using the analysis results, the power customized resonator (PCR) not only for deriving sufficient output power from the transmitter (Tx) but also for appropriately distributing the received power to the various and multiple Rx's is proposed. In addition to the PCR, the Tx unit is designed to work as a load-dependent voltage source using a differential Class-E power amplifier (PA) through a wide range of load impedances. Therefore, the Tx can naturally adapt to the required Tx power levels with a high efficiency corresponding to various Rx configurations without additional tunable circuits or adaptive control schemes. The WPT system, including the load-dependent voltage source for the Tx, full-bridge rectifiers for the Rx's, and the proposed PCR, was designed for the 6.78 MHz frequency band. The proposed system is validated for use with multiple mobile devices by conducting experiments with nine charging cases using three types of Rx's. For all cases, high system efficiencies of 70.7-85.5% were maintained over received power levels of 8.6-45.7 W at a charging distance of 30 mm, and each of the three types of Rx's were experimentally verified to receive sufficient power.