Rectification Efficiency Research Articles

A 2.4 GHz High-Efficiency Rectifier Circuit for Ambient Low Electromagnetic Power Harvesting.

A novel 2.4 GHz high-efficiency rectifier circuit suitable for working under very-low-input electromagnetic (EM) power conditions (-20 to -10 dBm) is proposed for typical indoor power harvesting. The circuit features a SMS7630 Schottky diode in a series with a voltage booster circuit at the front end and a direct-current (DC)-pass filter at the back end. The voltage booster circuit consists of an asymmetric coupled transmission line (CTL) and a high-impedance microstrip line (of 100 Ω instead of 50 Ω) to significantly increase the potential at the diode's input, thereby enabling the diode to operate effectively even in very-low-power environments. The experimental measurements show that the microwave direct-current (MW-DC) conversion efficiency of the rectifier circuit reaches 31.1% at a -20 dBm input power and 62.4% at a -10 dBm input power, representing a 7.4% improvement compared to that of the state of the art. Furthermore, the rectifier circuit successfully shifts the input power level corresponding to the peak rectification efficiency from 0 dBm down to -10 dBm. This design is a promising candidate for powering low-energy wireless sensors in typical indoor environments (e.g., the home or office) with low EM energy density.

Quantum Rectification Based on Room Temperature Multidirectional Nonlinearity in Bi2Te3.

Recent interest in quantum nonlinearity has spurred the development of rectifiers for harvesting energy from ambient radiofrequency waves. However, these rectifiers face efficiency and bandwidth limitations at room temperature. We address these challenges by exploring Bi2Te3, a time-reversal symmetric topological quantum material. Bi2Te3 exhibits robust room temperature second-order voltage generation in both the longitudinal and transverse directions. We harness these coexisting nonlinearities to design a multidirectional quantum rectifier that can simultaneously extract energy from various components of an input signal. We demonstrate the efficacy of Bi2Te3-based rectifiers across a broad frequency range, spanning from existing Wi-Fi bands (2.45 GHz) to frequencies relevant to next-generation 5G technology (27.4 GHz). Our Bi2Te3-based rectifier surpasses previous limitations by achieving a high rectification efficiency and operational frequency, alongside a low operational threshold and broadband functionality. These findings enable practical topological quantum rectifiers for high-frequency electronics and energy conversion, advancing wireless energy harvesting for next-generation communication.

A Novel 10-Watt-Level High-Power Microwave Rectifier with an Inverse Class-F Harmonic Network for Microwave Power Transmission

A novel 10-Watt-Level high-power microwave rectifier with an inverse Class-F harmonic network for microwave power transmission (MPT) is presented in this paper. The high-power microwave rectifier circuit comprises four sub-rectifier circuits, a 1 × 4 power divider, and a parallel-series dc synthesis network. The simple inverse Class-F harmonic control network serves dual roles: harmonic control and impedance matching. The 1 × 4 power divider increases the RF input power fourfold, reaching 40 dBm (10 W). The parallel-series dc synthesis network enhances the resistance to load variation. The high-power rectifier circuit is simulated, fabricated, and measured. The measurement results demonstrate that the rectifier circuit can reach a maximum RF input power of 10 W at 2.45 GHz, with a maximum rectifier efficiency of 61.1% and an output dc voltage of 23.9 V, which has a large application potential in MPT.

Array of resonant-type spin-torque diodes as a broadband rectifier: Numerical studies

In this paper, we propose a new approach for constructing broadband rectifiers from resonant-type in-plane spin-torque diodes (STDs). The intrinsic bandwidth of such STDs constrained by the ferromagnetic resonance linewidth of the corresponding magnetic tunnel junction’s is relatively narrow, which is a significant limitation. To address this issue, we propose the implementation of an array of these STDs, each with a distinct resonance frequency. By ensuring that the frequency difference between adjacent STDs is smaller than their individual bandwidths, we achieve a device capable of rectifying signals over a much wider frequency range. To verify the effectiveness of our approach, we have performed analytical calculations based on the Landau–Lifshitz–Gilbert equation with the Slonczewski term, complemented by macrospin modeling and full-scale micromagnetic simulations to account for thermal fluctuations and local magnetization inhomogeneities. Our results demonstrate that an STD array can effectively function as a broadband energy harvester, maintaining near-constant rectification efficiency across a broad frequency range. This research establishes the groundwork for the development of broadband energy harvesters based on STD arrays, with potential applications in various fields requiring efficient energy conversion across a wide frequency spectrum.

Origins of Giant Anisotropic Phonon Heat Transfer in True‐1D van der Waals Material

AbstractThermal rectification devices, which facilitate preferential heat flow in a singular direction, stands as pivotal tools in the realization of solid‐state thermal circuits. 1D atomic chains, exhibit heightened thermal rectification efficiency owing to their exceptional directional heat conduction properties. These will find widespread utility in many applications, encompassing areas such as cooling, energy harvesting, and thermal isolation systems. However, unlike quasi‐1D materials, the intrinsic anisotropic heat transport in true‐1D atomic chains is yet to be systematically studied. Herein, the origins of the anisotropic heat transfer in three representative 1D structures (TaSe3 and BaTiS3 marked as quasi‐1D, MoI3 labeled as true‐1D) is first investigated by integrating a first‐principles density functional theory‐based framework of two‐channel heat conduction model. In contrast to quasi‐1D, MoI3 exhibits a giant anisotropy of lattice thermal conductivity (κL) in chain‐ and cross chain‐directions with a high ratio up to ≈20, which far exceeds the previous report for HfTe5 and ZrTe5. Such unique heat transfer reveals comprehensively by charge‐sharing and transferred charges, p‐‐d orbital hybridization and Young's modulus changes, induces an exceptionally large anisotropy. This study presents a high‐performance implementation of thermal rectification designed to regulate directional heat current, demonstrating its potential applicability in solid‐state thermal circuits.

Numerical and analytical transport of Brownian particles in corrugated deformable channels: Current fluctuations and rectification efficiency

Numerical and analytical transport of Brownian particles in corrugated deformable channels: Current fluctuations and rectification efficiency

Thermal Rectification Modulation of Parallel Multiple Carbon/Boron Nitride Heteronanotubes.

Thermal rectification (TR) efficiency has always been an important concern for thermal rectifiers. However, in practical terms, the amount of heat conduction is equally not negligible. To get high values on both of them, the carbon nanotube arrays with high thermal conductivity and large heat conduction areas were considered, along with carbon/boron nitride heteronanotubes (CBNNTs) with excellent TR property. In our work, multiple CBNNT models are constructed, and the TR ratio under different conditions is investigated using nonequilibrium molecular dynamics, with double CBNNTs (D-CBNNTs) aligned in parallel as the main analytical object. It is shown that weakening the intertube coupling is an available way to enhance the TR ratio, and adjusting the heteronanotube length and spacing can also effectively regulate the TR. In the process of changing the coupling coefficient, we analyzed both phonon changes and atomic vibrations and got a good correspondence, and the BN region is more variable in D-CBNNTs. In addition, the covariation of phonon localization and intertube phonon exchange with the coupling coefficient results in an invariant backward heat flux in the D-CBNNT. Furthermore, by adjusting the carbon proportion and lowering the coupling coefficient in the model, an excellent TR ratio in four CBNNTs was obtained and its heat flux is even larger than the value at a carbon percentage of 50% in larger coupling. We fully utilized the phonon density of states, phonon participation rate, and mean square displacement. Our results demonstrate the possibility of multiple CBNNTs as thermal rectifiers and provide theoretical guidance for heteronanotube arrays to be applied.

Ge quantum well channel P-MOSFET for 2.45 GHz wireless weak energy harvesting

Wireless energy harvesting is an important application of microwave wireless energy transmission system, but due to the weak energy of RF signals in the 2.45 GHz band, its rectification efficiency is not ideal. As one of the core rectifier components of wireless weak energy harvesting system, the performance of MOSFET determines the rectification efficiency of the system, and its optimized design to improve the rectification efficiency is an important direction of current research in the field. In view of this, this paper proposes and designs Ge quantum well channel PMOS for wireless weak energy harvesting at 2.45 GHz, aiming to improve the rectification efficiency of wireless weak energy harvesting systems. Starting from adjusting the structural physical parameters of the MOS tubes, the absolute value of the threshold voltage is reduced in the weak energy density region, which in turn improves the rectification efficiency of the device. Then, the novel diode connection with the introduction of substrate bias effect is compared with the conventional connection using an ADS simulation circuit, and the simulation results show that the leakage current is smaller and the rectification efficiency is higher under the novel connection. On this basis, a Ge quantum well channel PMOS device is proposed. Compared with the Ge surface channel, the hole mobility of the quantum well channel will be greatly improved, and its rectification efficiency can also be improved. The device is connected to the rectifier circuit with a novel connection and simulated using Silvaco's Mixedmode module. The results show that the rectification efficiencies of the Ge quantum well channel MOS reach 13.53 % and 32 % at low input powers of −20.34 dBm and −6.28 dBm, respectively, which are 3.3 and 1.14 times higher than those of the conventional surface channel MOS.

A 2.0–3.0 GHz GaN HEMT-Based High-Efficiency Rectifier Using Class-EFJ Operating Mode

In this paper, a CGH40010F GaN-based wideband RF rectifier with high rectification efficiency is presented. A novel continuous class-EFJ-mode rectifier is constructed by combining a continuous class-J-mode rectifier and class-EF-mode rectifier under specific impedance conditions. This novel continuous class-EFJ-mode rectifier has high rectification efficiency and wide bandwidth at the same time. For validation, a wideband high-efficiency class-EFJ-mode rectifier functioning within the 2.0–3.0 GHz range is designed, fabricated, and measured. The measurements indicate that, with an input power of 40 dBm and a resistance of 72 Ω on the dc load, the implemented rectifier sustains a rectification efficiency exceeding 60% across its entire operational frequency band. Meanwhile, the dimensions of the circuits are only 3 cm × 3.1 cm.

Near-field radiative thermal rectification assisted by Bi2Se3 sheet

The ability to control heat flux at the nanoscale opens up numerous exciting possibilities in modern electronics and the field of information processing. In this research, we propose a design with the focus on achieving efficient thermal rectification at moderate gap and relatively low temperature. This study centers on near-field thermal radiation between temperature dependent indium antimonide (InSb) and silicon carbide (3C-SiC) coated with bismuth selenide (Bi2Se3). Our investigation sheds light on the critical role played by the Bi2Se3 layer in enhancing various key parameters, including the net radiative flux, and thermal rectification efficiency (η). We achieved a substantial improvement in the η of a near-field radiative thermal rectifier (NFRTR) due to the presence of the Bi2Se3 sheet. This enhancement is contingent on factors such as the Fermi energy (Ef) of Bi2Se3, emitter temperature, and the vacuum gap (d). Our study culminated in the identification of an optimal design, achieving an impressive η of 75% at an emitter temperature (TH) of 350 K, with vacuum gap (d) set to 20 nm. Furthermore, increasing TH to 500 K resulted in even more promising outcomes, with the highest η reaching 93%. The need for operating the optimized device at moderate temperatures is to strike a balance between efficiency, safety, cost-effectiveness, and material compatibility. These findings represent a significant step forward in the development of efficient Bi2Se3-based NFRTRs, paving the way for future applications in thermal management, energy conversion systems, and thermal logic gates.

A Method for Improving Radio Frequency Rectification Efficiency in Low-Resistance Loads

Present radio frequency (RF) rectifiers usually suffer from poor power conversion efficiency (PCE) at low-resistance loads, and the currently proposed DC-DC converter cannot solve this problem well. Aiming at this above problem, we propose a novel DC-DC converter for rectifiers, which consists of a Boost–Buck circuit and a Buck circuit cascaded together to maintain high PCE at both high and low load resistance; the converter can also operate over a wide range of input powers. The proposed converter, along with a 2.45 GHz rectifier, was fabricated to verify its performance. With the converter, the load range of the rectifier when the overall PCE is over 50% was extended from 250 Ω–1250 Ω to 5 Ω–3000 Ω. The highest overall PCE reached up to 61% and the overall PCE at a small load of 5 Ω increased from 1.1% to 54%. The proposed converter can be used in wireless power transmission (WPT).

Rectification of heat current in Corbino geometry.

We prove analytically the ballistic thermal rectification effect (BTRE) in the Corbino disk characterized by an annular shape. We derive the thermal rectification efficiency (RE) and show that it can be expressed as the product of two independent functions, the first dependent on the temperatures of the heat baths and the second on the system's geometry. It follows that a perfect BTRE can be reached with the increase of the ratios of the heat baths' temperatures and of the radius of the outer edge to the inner edge of the disk. We also show that, by introducing a potential barrier into the Corbino disk, the RE can be greatly improved. Quite remarkably, by an appropriate choice of parameters, the thermal diode effect can be reversed. Our results are robust under variation of the Corbino geometry, which may provide a flexible route to manipulate the heat flow at the nanoscale.

Design of a transistor‐based broadband high‐efficiency class‐F−1 rectifier

AbstractThis brief proposes an innovational method to design a broadband high‐efficiency transistor‐based rectifier with high rectification efficiency. The theory of the class‐F−1 rectifier with the input second harmonic component is explored. Moreover, the mathematical variations of rectification efficiency and load/source impedances versus several crucial design parameters are established. The variation relationships indicate that the rectification efficiency can roughly maintain constant across a large input second harmonic range, resulting in more available design impedances. Thus, this provides the possibility to design wideband rectifiers. For validation, a broadband high‐efficiency class‐F−1 rectifier (operating in 1.6–2.6 GHz) using a GaN transistor is designed, assembled, and measured. Measurements indicate a rectification efficiency of between 72.1% and 82.4% under the condition of Rdc = 67 Ω and Pin = 40 dBm. The realized rectifier exhibits the largest relative bandwidth compared with transistor‐based rectifiers reported before. The methodology presented in this brief provides a promising approach for broadband high‐efficiency GaN HEMT‐based rectifiers.

Superconducting Diode Effect in a Constricted Nanowire

AbstractDue to isotropic superconducting properties and the lack of breaking of inversion symmetry for conventional s‐wave superconductors, a nonreciprocal superconducting diode effect is absent. Recently, a series of superconducting structures, including superconducting superlattice, and quantum‐material‐based superconducting Josephson junction, have exhibited a superconducting diode effect in terms of polarity‐dependent critical current. However, due to complex structures, these composite systems are not able to construct large‐scale integrated superconducting circuits. Here, it is demonstrated that the minimal superconducting electric component‐superconducting nanowire‐based diode with a nonreciprocal transport effect under a perpendicular magnetic field, in which the superconducting to normal metallic phase transition relies on the polarity and amplitude of the bias current. These nanowire diodes can be reliably operated near at all temperatures below the critical temperature, and the rectification efficiency at 2 K can be more than 24%. Moreover, the superconducting nanowire diode is able to rectify both square wave and sine wave signals. Combining the superconducting nanowire‐based diodes and transistors, superconducting nanowires hold the possibility to construct novel low‐dissipation superconducting integrated circuits.

Research on internal flow characteristics of the planar conical tube for valveless piezoelectric micropump

Abstract As the most commonly used driving and executing components in microfluidic systems, valveless piezoelectric micropumps have broad application prospects in numerous fields. The steady and unsteady characteristics of planar conical tubes for valveless piezoelectric micropumps were simulated using CFX software at different pressure amplitudes and driving frequencies. The aim was to obtain the factors affecting the flow performance of the valveless piezoelectric micropump. The results show that the numbers of Remax in both diffusion and contraction directions of the planar conical tube increase with increasing pressure. When the number of Wo is lower, the number of Remax under a steady state is approximately equal to that under an unsteady state, and the maximum relative deviation is only 0.25%. The greater the Wo number, the smaller the velocity on the minimum flow section, and the more significant the velocity change. The rectification efficiency η of the valveless piezoelectric micropump and the efficiency λ of the planar conical tube both increase with increasing pressure under steady conditions, and the maximum values can be reached at 11.2% and 1.56, respectively.

High breakdown voltage of 1.3 kV and low turn-on voltage of 0.48 V β-Ga2O3 heterojunction barrier Schottky diode with tungsten Schottky contact

β-Ga2O3 power diodes were expected to possess low turn-on voltage (V on), low reverse leakage (J R), and high blocking capability for low power losses. In this work, a low V on (0.48 V) β-Ga2O3 heterojunction barrier Schottky diode (HJBS) with tungsten Schottky contact was achieved. Benefitting from the lateral depletion of p+-NiO to suppress J R originating from the low Schottky barrier, the blocking capability of β-Ga2O3 HJBS was enhanced. The spacing width of p+-NiO was systematically studied to reveal its modulation effect on forward and reverse characteristics. This work provides a promising strategy for improving rectifier efficiency of β-Ga2O3 diodes.

Numerical analysis of MIM nano-rectenna with metasurface for infrared energy harvesting

A novel approach for infrared (IR) energy harvesting through the integration of a resonating metasurface with a metal-insulator-metal (MIM) nano-rectenna is presented. The absorption of IR radiation at 28.3 THz is significantly enhanced through the localization of surface plasmons with the integration of a periodic metasurface on the top of the log spiral MIM rectenna. Additionally, a ground plane is introduced on the backside of the structure to further enhance absorption characteristics. Extensive characterization analysis of the antenna's absorbed E-fields for incident 28.3 THz radiation is conducted with and without the integrated metasurface using full-wave numerical simulation. Also, the rectification properties (I/V, resistivity, and responsivity) are studied with variations in metal (Au, Al, Ag, and Cu) and five different insulators (Al2O3, Cu2O, Ta2O5, TiO2, and ZnO) types. The results demonstrate that the presence of the metasurface enhances the absorbed IR E-field by the rectenna to levels of 80–90%. Furthermore, exceptional harvesting performance, including E-field, current density, resistivity, and rectification efficiency (responsivity), is achieved with the asymmetric Au-ZnO-Cu and Au-ZnO-Ag MIM and metasurface rectenna structures. The proposed design strategies can lead to the development of highly efficient IR energy harvesters in the future.

Novel Ge-Based Plasma TFET with High Rectification Efficiency for 2.45 GHz Microwave Wireless Weak Energy Transmission.

The enhancement of rectification efficiency in 2.45 GHz microwave wireless weak energy transmission systems is centred on rectifier device selection. The overall rectification efficiency of traditional rectifier devices is low in weak energy density situations, failing to fulfil the commercial requirements of this region. The subthreshold swing of the emerging device TFET exceeds 60 mV/dec, which has the advantages of a large open-state current and a small off-state current in the corresponding region of the weak energy density. In view of this, this paper designs a double-gate plasma rectifier TFET with an embedded n+ heavily doped layer on the basis of a PNPN-structured TFET, where the device is simulated with the MixedMode module of Silvaco TCAD 2018, the rectification efficiency at -10 dBm is 44.12%, which is 10.61% higher than that of the PNPN-TFET, and the efficiency in the weak energy density region is generally 10% or more than that of commercial HSMS devices, showing obvious rectification advantages.

Optimal Power Allocation of Receiving Antenna for Rectification Efficiency Improvement in Wireless Power Transfer System

Optimal Power Allocation of Receiving Antenna for Rectification Efficiency Improvement in Wireless Power Transfer System

Edelstein Effect Induced Superconducting Diode Effect in Inversion Symmetry Breaking MoTe2 Josephson Junctions

AbstractSuperconducting diode effect (SDE) with nonreciprocal supercurrent transport has attracted intense attention recently, not only for its intriguing physics, but also for its great application potential in superconducting circuits. It is revealed in this work that planar Josephson junctions (JJs) based on type‐II Weyl semimetal (WSM) MoTe2 can exhibit a prominent SDE due to the emergence of asymmetric Josephson effect (AJE) in perpendicular magnetic fields. The AJE manifests itself in a very large asymmetry in the critical supercurrents with respect to the current direction. The sign of this asymmetry can also be effectively modulated by the external magnetic field. Considering the special noncentrosymmetric crystal symmetry of MoTe2, this AJE is understood in terms of the Edelstein effect, which induces a nontrivial phase shift in the current phase relation of the junctions. Besides these, it is further demonstrated that the rectification of supercurrent in such MoTe2 JJs with the rectification efficiency up to 50.4%, unveiling the great application potential of WSMs in superconducting electronics.