Optimal Input Power Research Articles

Performance evaluation on a novel split thermoelectric system driven by solar energy for electric vehicle seats

This paper proposed a novel split thermoelectric system coupled with a photovoltaic panel for electric vehicle seats. The system separates the hot and cold ends of the thermoelectric device over a long distance with the flexible intermediate conductor, which solves the problem of poor heat dissipation at the hot end resulted from the integration of traditional TEC with the vehicle seats and improves the cooling and heating performance. A three-dimensional heat transfer model was established by COMSOL software to study the temperature field and the comprehensive performance. The results demonstrate that the system can maintain the seat temperatures in 27–30 °C in summer and 18–25 °C in winter, and there exists an optimum input power to maximize the COP. In addition, the seat temperature can be reduced from 60 °C to 31 °C in just 20 min under maximum heating load. The system performance is closely linked to the structure of the middle conductors, heat dissipation, solar radiation intensity, and ambient temperature. In winter, the power consumption of the system is reduced by about 84 % compared to the positive temperature coefficient thermistor with the COP being increased by 5.17. The contribution of the photovoltaic panel based on the studied conditions can save about 215.26 kWh of energy per year, and increase the driving distance of electric vehicles by approximately 1435 km.

Optimal parameters for the efficient microwave ablation of liver tumor from the 3D-IRCADb-01 database.

Purpose: Microwave ablation is a minimally invasive thermal modality for cancer treatment with high survival and low recurrence rates. Despite the unquestionable benefits of microwave ablation, the interaction between the medical instruments and the tissue may cause damage to the healthy tissue around the tumor. Such damages can be removed by clarifying the conditions for their development. In addition to clinical methods, computer simulations have become very effective tools for optimizing microwave ablation performance. Methods: The study was focused on the determination of the optimal input power for complete microwave tumor ablation with an ade-quate safety margin avoiding injury to the surrounding healthy tissue. In three-dimensional simulations, the liver tumor model was based on a real tumor (1.74 cm × 2.40 cm × 1.43 cm) from the 3D-IRCADb-01 database. Calculations were performed for a 10-slot antenna proven to achieve a higher degree of ablation zone localization than a standard single-slot antenna. The temperature-dependent dielectric and thermal properties of healthy and tumoral liver tissue, blood perfusion, and water content were included in the model. Results: The obtained simulation results revealed that the proper choice of input power ensures that necrotic tissue is mainly located in the tumor with minimal damage to the surrounding healthy tissue. Conclusions: This study may represent a step forward in the planning of individual microwave ablation treatment for each patient.

A High-Efficiency Rectifying Metasurface With Four Operating Bands

In this letter, a multiband rectifying metasurface is proposed. Two resonant modes are excited through the metasurface structure, and others are introduced by the trapezoidal patch while the resonant intensity is increased. Finally, RF energy in the quad-band can be captured by the metasurface with the four resonant modes. The rectification efficiency is analyzed at different conditions, and the optimal load and input power level of the system are obtained, which improves the synthetic rectification efficiency of the system. A 6 × 6 array is fabricated and measured. Experimental results show that the proposed rectifying metasurface can capture RF energy at 1.7 GHz, 2.4 GHz, 3.8 GHz, and 5.3 GHz. The peak RF to DC efficiency of the system is 72.1% at the incident power of 0 dBm. Compared with other reports, the proposed one can capture more bands of RF energy with relatively lower incident power level requirements and high efficiency. It may be applied to energy absorption scenarios in RF environments, such as wireless power transmission.

Modulation instability in long distance φ-OTDR system

Recent trends in long distance phase-sensitive optical time-domain reflectometer (φ-OTDR) have led to a proliferation of studies on modulation instability (MI). However, most of these studies overlook the inaccuracies of MI gain spectrum based on the linear stability analysis of the nonlinear Schrödinger equation in the case of long distance over about 10 km. Here, we conducted a comprehensive exploration of MI characteristics in the φ-OTDR system, including the effects of input power, detection distance, and background noise on the MI evolution process. Experiments confirmed the presence of an intrinsic spectral component of MI surrounding the signal in long-distance detection, which has not been reported previously. Further, we proposed a fitting expression using numerical simulation to determine the optimal input power for the φ-OTDR system. Compared to traditional threshold formulas, it does not require complex theoretical derivations and demonstrated significantly higher accuracy, particularly in systems with ultra-long detection distances. The deviation was less than 10%, demonstrating its potential as a more precise and simplified method of determining optimal input power. This could help improve the efficiency and reliability of these systems, leading to further advancements in the field of MI research.

Self-Powered Polarization-Reconfigurable Rectenna for Wireless Power Transfer System

This paper proposes a novel self-powered polarization-reconfigurable rectenna for wireless power transfer (WPT) systems. A three-state-reconfigurable network is designed, which is realized by two 3 dB bridges sharing a branch integrated with PIN diodes. The patch antenna can be excited to receive distinct polarized waves at 5.8 GHz by controlling PIN diodes’ ON or OFF state. In addition, a high-efficiency rectifier network includes two rectifier circuits integrating with a circulator for optimal input power. The function of the rectifier circuit 1 is to convert the radio frequency (RF) power in the power transfer link into direct current (DC) power. and rectifier circuit 2, as a part of the polarization control link, aims to use the energy reflected by the rectifier circuit 1 to provide a DC bias for the PIN diodes. Without an external DC power source. Finally, a WPT system is established based on the proposed self-powered polarized reconfigurable rectenna. The measured results show that the proposed rectenna has a maximum conversion efficiency of 66% at 5.8 GHz and a conversion efficiency higher than 50% in the incident power range from 21 dBm to 30 dBm. It can flexibly adjust the polarization state without an extra DC power source, realizes efficient wireless power transmission, and can be widely used in WPT systems for different applications.

A dual-band, wide-angle absorbing metasurface for EM energy harvesting and wireless power transfer

In this paper, a dual-band metasurface is designed for electromagnetic (EM) applications in the sub-6G band. The metasurface consists of a hexagonal Complementary Split Ring Resonator (CSRR) absorber array, a dual-band impedance-matched rectifier network, and a load. The CSRR metasurface absorber is designed by combining a hexagonal prism and a hexagonal ring. The proposed absorber is surrounded by metal vias to improve the operating stability of each cell. By integrating the absorber array with the rectification network, the system redundancy and power loss are reduced. The designed metasurface is capable of harvesting EM energy in different frequencies using one port, even at a wide incidence angle. Dual-band rectification within the Sub-6G range is achieved by the rectification network at low input power density. We fabricated and measured a 3 × 3 hexagonal CSRR metasurface array, and the experimental result shows that the optimal input power is 2 dBm (the incident power density is 169 μW/cm2), the radio frequency(RF)-to-direct current(DC) efficiencies are 57.6% and 47% at 3.8 and 5.2 GHz, respectively.

Efficient Monolithic SAW Convolver Using Poly(3-Hexylthiophene)

The demonstration of organic semiconductor based monolithic surface acoustic wave (SAW) convolver has been reported. The characteristic low availability of intrinsic free charge in organic semiconducting polymer favors depletion mode of operation, increasing the effective nonlinear interactions. Input signals at different combinations of frequencies were used and the observed convolved signals showed notably high efficiency without the need of an applied bias. The record high efficiency has been -13.2 dBm for 42 MHz input signals at optimum input power of -6 dBm. The experimental results and the convolution mechanism were verified via numerical analysis in MATLAB.

Theoretical Analysis of Spectral Broadening Through Saturable Photoexcited-Carrier Refraction in Graphene-Covered Nanowires

We perform a thorough study of the spectral broadening of short and intense pulses propagating in graphene- covered nanowires departing from a saturable photoexcited-carrier refraction (SPCR) model. In particular, we put forth an analytical expression for the instantaneous frequency of the traversing pulse, in a relevant limiting case, which allows to calculate the spectral broadening and frequency shift experienced by the pulse and elucidate the role of its initial chirp. Most interestingly, both the spectral broadening and frequency shift are found to be maximized for an optimal input power. In all cases, results from analytical expressions are found to be in excellent agreement with numerical solutions of the propagation equations.

Performance analysis of a new thermal management for thermoelectric cooler

In this paper, a new thermal management method applied to thermoelectric cooler (TEC) is proposed by combining radiative sky cooler (RSC) with air cooling, which can improve cooling capacity and reduce power consumption over a standalone air cooling. The system is based on radiative sky passive cooling and supplemented by air cooling for heat dissipation. A steady-state model is developed to analyze the system performance in terms of many parameters, including the input current, the area of RSC, the cold/hot side temperature, ambient temperature and convective coefficient of air. The results show that the system can significantly increase the cooling capacity and reduce the attenuation of heat dissipation capacity at high ambient temperature compared with a standalone air cooling system. It can achieve complete passive cooling by RSC without any energy consumption when the TEC input power is low. Although increasing the RSC surface area and air cooling intensity can further enhance the cooling capacity, there is a reasonable value between the two, depending on the TEC cold and hot side temperatures. Moreover, it has an optimal input power for different target cooling capacity of TEC, which can minimize the required RSC area.

On the Capacity of Gaussian MIMO Channels With Memory

The operational capacity of Gaussian MIMO channels with memory was obtained by Brandenburg and Wyner (1974) under certain mild assumptions on the channel impulse response and its noise covariance matrix, which essentuially require channel memory to be not too strong. This channel was also considered by Tsybakov (2006) and its information capacity was obtained in some cases. It was further conjectured, based on numerical evidence, that these capacities are the same in all cases. This conjecture is proved here. An explicit closed-form expression for the optimal input power spectral density matrix is also given. The obtained result is further extended to the case of joint constraints, including per-antenna and interference power constraints as well as energy harvesting constraints. These results imply the information-theoretic optimality of OFDM-type transmission systems for such channels with memory.

An Analysis of Microwave Ablation Parameters for Treatment of Liver Tumors from the 3D-IRCADb-01 Database.

Simulation techniques are powerful tools for determining the optimal conditions necessary for microwave ablation to be efficient and safe for treating liver tumors. Owing to the complexity and computational resource consumption, most of the existing numerical models are two-dimensional axisymmetric models that emulate actual three-dimensional cancers and the surrounding tissue, which is often far from reality. Different tumor shapes and sizes require different input powers and ablation times to ensure the preservation of healthy tissues that can be determined only by the full three-dimensional simulations. This study aimed to tailor microwave ablation therapeutic conditions for complete tumor ablation with an adequate safety margin, while avoiding injury to the surrounding healthy tissue. Three-dimensional simulations were performed for a multi-slot microwave antenna immersed in two tumors obtained from the 3D-IRCADb-01 liver tumors database. The temperature dependence of the dielectric and thermal properties of healthy and tumoral liver tissues, blood perfusion, and water content are crucial for calculating the correct ablation time and, thereby, the correct ablation process. The developed three-dimensional simulation model may help practitioners in planning patient-individual procedures by determining the optimal input power and duration of the ablation process for the actual shape of the tumor. With proper input power, necrotic tissue is placed mainly in the tumor, and only a small amount of surrounding tissue is damaged.

Hybrid Energy Efficiency Friendly Frequency Domain TR Algorithm Based on PSO Algorithm Evaluated by Novel Maximizing HPA Efficiency Evaluation Criteria

Smart Grids (SGs) expedite secure, large-scale and efficient two-way communication between the power supply and management, but under a sophisticated 5G communication infrastructure, the multi carrier system is the principle system. The high peak-to-average power ratio (PAPR) is one of the significant limitations of the 5G multi carrier (MC) system, as it impedes the efficient design of the 5G analogue front end. Tone reservation (TR) is a highly efficient scheme without signal distortion, which is designed by increasing the freedom in the frequency domain for PAPR reduction. In this paper, a particle swarm optimization (PSO) based TR (PSO-TR) scheme proceeding with an optimal input power back off-modulation error ratio (IBO-MER) convergence criterion is proposed to improve high power amplifier (HPA) efficiency for OFDM systems. A probabilistic analysis of TR predistribution and freedom in the frequency domain, in relationship with the amplitude of its constituent samples, is carried out. This yields the theoretical framework employed in design of the proposed high computing-enhanced solutions. The proposed PSO-TR essentially make the frequency domain distribution and operation itself adaptive, that is, it adjusts to comply with the changing HPA efficiency and redundant cost during application runtime.

Cost-effective and performance analysis of thermoelectricity as a building cooling system; experimental case study based on a single TEC-12706 commercial module

Application of thermoelectricity as the building air cooling system has not been commercialized yet. However, remarkable eco-friend characteristics of thermoelectricity encourages the researchers to enthusiastically work on different aspects of Peltier cooler to make its performance competitive with other cooling techniques. The contribution of this research is to explicitly clarify the real cooling cost made by a single popular and affordable thermoelectric module in the market under different working conditions and identify how the effective parameters can impact the cooling cost and performance of the cooler. To reach the aim of this research, a laboratory-scale thermoelectric air-water based cooler is fabricated to obtain the behavior of thermoelectric cooler under different air flow rates, room (air intake) temperatures, input power and so on. In the next step, the obtained results are employed to analyze the cost-effective features of the cooler under the mentioned working conditions. Based on the results, cost per kWh of cooling by a thermoelectric module can vary between 0.7 and 1.4 dollar depending on the range of mentioned parameters. It is interesting that, an extremum point is observed for input power of 23 W through which the cost of air cooling process is minimized and then is increased. Hence, number of employed thermoelectric modules in real big size cooler will be a key parameter to allocate an optimum input power for any individual thermoelectric module. Moreover, the cost of cooling is reduced for warmer air temperatures which shows the suitability of thermoelectric coolers for hot regions.

Eight-Port Feed Radial Line Slot Antenna for Wireless Power Transmission

This article proposes a circular sector subarray to equalize input power to rectifiers and an eight-port radial line slot antenna (RLSA) with the circular sector subarray. Rectifiers are nonlinear components and have the optimum input power. To maximize RF-DC conversion efficiency, the input power to the rectifiers should be the uniform and optimum input power. The circular sector subarray configuration enables uniform power feeding to multiple ports by dividing the circular aperture into circular sector shapes. The eight-port RLSA has eight microstrip lines to divide the circular aperture to eight circular sector subarrays. The design methodology of the eight-port RLSA is detailed and it is fabricated by printed circuit board technology. The fabricated antenna showed good agreement with the simulated characteristics. Transmission between the eight-port RLSA and a one-port RLSA was measured, and 60% transmission with 280-mm separation was confirmed. Transmission to each port has a 1.4 to 3.4-dB deviation because of the circumference deviation of the one-port antenna aperture distribution. This deviation can be improved by enhancing the uniformity of the one-port antenna aperture distribution.

Enhancement of luminous flux of InGaAlP-based low-power SMD LEDs using substrates with different thermal resistances

PurposeOptimization of light-emitting diodes’ (LEDs’) design together with long-term reliability is directly correlated with their photometric, electric and thermal characteristics. For a given thermal layout of the LED system, the maximum luminous flux occurs at an optimal electrical input power and can be determined using a photo-electro-thermal (PET) theory. The purpose of this study is to extend the application of the luminous flux equation in PET theory for low-power (LP) LEDs.Design/methodology/approachLP surface-mounted device LEDs were mounted on substrates of different thermal resistances. Three LEDs were attached to substrates which were flame-retardant fiberglass epoxy (FR4) and two aluminum-based metal core printed circuit boards (MCPCBs) with thermal conductivities of about 1.0 W/m.K, 2.0 W/m.K and 5.0 W/m.K, respectively. The conjunction of thermal transient tester and thermal and radiometric characterization of LEDs system was used to measure the thermal and optical parameters of the LEDs at a certain range of input current and temperature.FindingsThe validation of the extended application of the luminous flux equation was confirmed via a good agreement between the practical and theoretical results. The outcomes show that the optimum luminous flux is 25.51, 31.91 and 37.01 lm for the LEDs on the FR4 and the two MCPCBs, respectively. Accordingly, the stipulated maximum electrical input power in the LED datasheet (0.185 W) is shifted to 0.6284, 0.6963 and 0.8838 W between the three substrates.Originality/valueUsing a large number of LP LEDs is preferred than high-power (HP) LEDs for the same system power to augment the heat transfer and provide a higher luminous flux. The PET theory equations have been applied to HP LEDs using heatsinks with various thermal resistances. In this work, the PET theory luminous flux equation was extended to be used for Indium Gallium Aluminum Phosphide LP LEDs attached to the substrates with dissimilar thermal resistances.

Multiband asymmetric radio frequency to direct current converter circuit for wireless power transfer

AbstractThis article presents the multiband asymmetric radio frequency (RF) to direct current (DC) converter circuit for the wireless power transfer (WPT) applications. The proposed circuit is composed of a power divider, novel asymmetric multiband matching circuit and RF Schottky diode quadrupler voltage rectifier circuit. Unlike the conventional narrow band quadrupler using two Greinacher cells with opposite polarities, the proposed circuit aims to cover the multifrequency bands, which are the cell phone 1.8–2.1 GHz, the industrial, scientific, and medical (ISM) bands 2.4–2.5 GHz and 5.725–5.875 GHz. The interested RF input power range of −10 to 20 dBm for the WPT application is focused. The measured RF‐to‐DC conversion efficiency (η) of 50–65% at 1.8–2.1 GHz, 65% at 2.45 GHz and 16% at 5.8 GHz are obtained at 10 dBm optimal input power.

MOORA and TOPSIS based selection of input parameter in solar powered absorption refrigeration system

ABSTRACT Absorption cooling using energy media like low-grade solar thermal energy and many other sources is of utmost importance for energy needs. To enhance the coefficient of performance of system, an experimentation using forced convection, air/water cooled absorber was carried out. The input power from 40 to 70 W is given to the generator with each case of the framework and found improvement in the coefficient of performance from 8.69% to 18.18% in water cooled absorber. To determine optimal input power, optimisation of the refrigeration systems is important. In this work, Multi-Objective Optimisation based on Ratio Analysis (MOORA) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) are used and observed that the best solution for input power is 40 W for water cooled absorber system and the ranking order is 1 > 3>4 > 2, i.e. (40 W > 60 W > 70 W > 50 W).

Gaussian basis expansion phase noise suppression method for CO-OFDM systems

In this paper, we propose a novel phase noise suppression method based on Gaussian basis expansion (GBE) for CO-OFDM systems. We analyze the basic phase noise suppression principle of GBE and then demonstrate it in optical OFDM transmission systems. Compared with common phase compensation (CPE), orthogonal basis expansion (OBE) and eigenvector basis expansion (EBE) schemes, the proposed GBE scheme has better phase noise fitting ability with similar computation complexity. Futhermore, no additional back to back (BTB) pre-training is needed for the GBE scheme. Performance improvements by the GBE is experimental validated in the QPSK/16-QAM OFDM system with different transmission scenarios (different number of pilots and input power). In the QPSK-OFDM system, after 160 km SSMF transmission, a Q-factor improvement of 1.7 dB and 0.5 dB are achieved compared with the CPE and OBE schemes at the optimum input power of -4 dBm, respectively. In the 16-QAM-OFDM system, the measured BER improved from 8.21×10-4 to 2.36×10-4 with the GBE scheme. To further verify the effectiveness of the GBE scheme, we change the laser linewidth and measure the long transmission distance performance by simulation, the results show that the GBE scheme can effectively increase the laser linewidth tolerance and extend transmission distance. When the linewidth is 2-MHz, the proposed GBE scheme can extend the transmission distance from 1120 km to 1540 km at the BER of 10-4. Experimental and simulation results show that the proposed GBE scheme is a promising alternative phase noise suppression for CO-OFDM system.

Blind back-propagation method for fiber nonlinearity compensation with low computational complexity and high performance.

In this paper, a blind back-propagation (BP) method for fiber nonlinearity compensation with low computational complexity and high performance is proposed. The BP method compensates the fiber chromatic dispersion step by step. Between two linear steps, the proposed method compensates the fiber nonlinearity with the nonlinear tap coefficients optimized by the nonlinear least square method (NLSM). Unlike the traditional BP method, the proposed method takes into account the SPM, the intra-channel XPM and the intra-channel FWM effects while it is purely blind and requires no prior information of the transmission link except the total accumulated chromatic dispersion, e.g., the BP step in the proposed algorithm can be set as an arbitrary value which has no connection to the physical span length. The computational complexity of the proposed method is much lower (less than 50%) than the conventional BP method with one step per span, because of the reduction of the total number of steps. Meanwhile, the method improves the nonlinearity compensation performance in comparison to the standard BP method with one step per span at the optimal input power while maintaining the same computational complexity.

Gain flattened C-band hybrid optical amplifier achieving high and flat gain over 32-nm bandwidth for dense wavelength division multiplexed system

Increase in data rate demand requires continuous improvement in existing optical amplification schemes. This work demonstrates optical amplification, simulating a hybrid combination of Er-Yb codoped fiber amplifier (EYDFA) and dual pump fiber optical parametric amplifier (FOPA). The proposed EYDFA–FOPA hybrid amplifier is investigated over a wavelength range of 1533–1565 nm for 160 × 10 Gbs − 1 dense wavelength division multiplexed (DWDM) system at 0.2-nm channel spacing. The parameters are optimized to achieve a flat gain of >28.4 dB, with a gain ripple of 2.09 dB at −20 dBm optimum input power per channel. Also, analysis at different input power shows that for higher input powers up to −5 dBm, an increase in gain ripple up to 5.07 dB is observed. Further, a comparison with EYDFA–single pump FOPA configuration shows that much better gain flatness is obtained for the proposed hybrid amplifier. The obtained high and flat gain, along with the low noise figure, justifies the feasibility of the proposed amplifier for applications in broadband long-haul DWDM systems.