In microwave power transmission systems, the performance of the rectifier plays a crucial role in determining the overall system efficiency. To improve the rated input power capability and rectification efficiency, a homojunction GaN Schottky barrier diode (GaN SBD) and the corresponding rectifier circuit were designed and fabricated. The proposed rectifier operates at 10.0 GHz and achieves a maximum input power of 700 mW with a rectification efficiency of up to $\text{8 5 \%}$.

Load frequency control (LFC) plays a key role in improving power system stability and economic security. This is becoming quite challenging with high renewable power penetration into the power grid, as renewable power is typically random and intermittent energy, which gives rise to a huge impact on power quality. This article proposes a robust distributed economic model predictive control (RDEMPC) to incorporate distributed economic optimization and robust control for achieving the frequency regulation task. The local robust controller consists of a nominal distributed model predictive control (DMPC) and an ancillary feedback law. The ancillary term is designed to effectively cope with the wind disturbance, based on the difference between the actual state and the nominal state. The economic indexes, especially the maintenance cost from the wind-power generation, have been incorporated into the RDEMPC design. The stability of the robust distributed economic model predictive controller can be guaranteed by finding a Lyapunov function for each generation area that decreases with time. Simulation on the multiarea hybrid power system demonstrates the effectiveness of the RDEMPC in both improving the economic performance and reducing the wind speed disturbance.

This study presents a heterogeneous integration micro-assembly process and circuit board packaging solution for GaN Schottky Barrier Diode (SBD) rectifiers, and innovatively constructs a hierarchical reinforcement learning strategy for optimizing SBD RF parameters. By establishing an optimization framework with the goal of efficiency in the load-input power two-dimensional space, a dual-layer optimization mechanism is employed: the high-level strategy dynamically selects optimization regions and parameter combinations, while the low-level strategy implements specific parameter adjustments. This approach effectively addresses the challenges of device parameter modeling and circuit design. Experimental data shows that the efficiency error for the SBD1 rectifier remains stable within 2%, and the average error for SBD2 is reduced to 1.5%. This method enables efficient and accurate optimization of RF parameters, providing a reliable technical pathway for the engineering application of Wireless Power Transmission systems.

This paper proposes a diode loss calculation method that considers the diode mounting effect, aiming to optimize the design of diodes and rectifiers in the field of wireless power transfer (WPT). Compared to traditional loss calculation methods, the proposed approach not only incorporates the intrinsic characteristics of the diode but also thoroughly analyzes the impact of mounting on parasitic parameters and power loss. To validate the effectiveness of the method, a class-F rectifier circuit operating at 5.8 GHz is designed. Under the conditions of 10W input power and 139 Omega load, the loss rate of the diode is calculated as 16.553% based on the method proposed in this paper, which aligns well with the software simulation results. Furthermore, the calculated diode loss is used as the heat source power for thermal analysis. The results indicate that the maximum temperature of the GaN diode reaches 244 degrees C, while other areas maintain temperatures around 66 degrees C. The local hot spot temperature is high but still within the allowable range. This research provides significant theoretical support and practical guidance for optimizing high-frequency performance and thermal management in rectifier circuit design.

This paper presents an advanced radio frequency (RF)–direct current (DC) power conversion architecture based on a multistage Cockcroft–Walton topology. The proposed design achieves an enhanced voltage conversion ratio while maintaining superior RF-DC conversion efficiency under low input power conditions. To address the inherent limitations of cascading Cockcroft–Walton topologies with class-F load networks, a novel ground plane isolation technique was developed, which utilizes the reverse-side metallization of the circuit board. A 5.8 GHz two-stage Cockcroft–Walton voltage multiplier rectifier was fabricated and characterized. Measurement results demonstrate that the circuit achieves a maximum output voltage of 7.4 V and a peak conversion efficiency of 70.5% with an input power of only 30 mW, while maintaining stable performance across varying load conditions. A comparison with a two-stage Dickson rectifier reveals that the Cockcroft–Walton rectifier exhibits superior output voltage and conversion efficiency. The proposed architecture delivers significant improvements in power conversion efficiency and voltage multiplication capability compared to conventional designs, establishing a new benchmark for low-power wireless energy harvesting applications.

A novel co-designing strategy is presented for an integrated rectifying metantenna, which combines rectification, absorption and electromagnetic signal reception functionalities for simultaneous wireless information and power transfer (SWIPT). The metasurface is constructed using periodic patch units arranged in front of a compact microstrip antenna. This arrangement effectively stimulates transverse electric (TE) and transverse magnetic (TM) surface waves, which ensures not only high gain but also optimal antenna matching. Furthermore, the metasurface incorporates rectifier diodes distributed partially, significantly enhancing energy conversion efficiency. The proposed rectifying metantenna operates at 5.8 GHz (an ISM band) and achieves a maximum energy conversion efficiency of 54.6% when subjected to an input power of 0 dBm. This accomplishment is particularly noteworthy when the metantenna is integrated into devices for data communication. The proposed rectifying metantenna boasts a range of merits including high integration and multifunctionality. These inherent attributes position it as a promising candidate for advanced IoT wireless communication systems, facilitating the generation of rectified DC power while receiving RF signals without the need for power splitter and time-switching used in conventional SWIPT systems.

Injection-locking technology is a primary way to solve the frequency instability and uncontrollable problems of a magnetron; however, conventional injection-locking theory ignores the free-running frequency fluctuation of a magnetron, which usually exists in vacuum sources. Herein, the injection locking of a magnetron, considering its free-running frequency fluctuation, is systematically studied based on statistics and probability theory. First, the output frequency of an injected magnetron with a specific hypothetical single free-running frequency is demonstrated. Then, the fluctuation of the unstable instantaneous frequency of a free-running magnetron could be statistically taken as a random variable, in which each element could be one specific single free-running frequency with a certain probability. By using the theorem of conditional probability and joint distribution, the probability density function of the output frequency of the injected magnetron can be derived. Analysis based on the derived equations indicates that the injection-locking bandwidth (BWL) is less than that calculated from Adler’s condition if the fluctuation of the free-running magnetron’s frequency is considered; moreover, BWL decreases with increasing free-running frequency bandwidth, while the peak frequency pulling bandwidth (BWP) increases. The experimental results show that BWL decreases from 5.8 to 4.8 MHz as the 3 dB bandwidth of the free-running magnetron spectrum increases from 0.38 to 1.05 MHz. Simultaneously, BWP increases from 6.8 to 10.8 MHz, which is consistent with the theoretical prediction. In general, this study illustrates the vital importance of the free-running frequency condition on the injection-locking results of a magnetron and develops the injection-locking theory.

This paper put forward a hybrid energy harvester for collecting RF and solar energy in quad-band (GSM-900/1800, ISM-2400 and WiMAX-3500). By introducing diverse parasitic structures, good impedance matching with unidirectional radiation is achieved in the multi-band. Below the solar antenna, a low-power rectifier circuit is employed to achieve broadband rectification. Under the input power of 0 dBm, and maximum RF-DC conversion efficiency of 56.94% is realized. Accordingly, the hybrid energy harvester collects RF and solar energy individually or simultaneously, and then converts it into DC for power supply. With a light intensity of 1500 lux, the solar cell obtains 1.732 mW, and the rectenna can harvest additional 0.37–0.405 mW power. The proposed RF–Solar energy harvester has the advantages of multi-frequency operation, high gain, and high energy harvesting conversion efficiency.

Considering the widespread application of magnetic sensors in the Internet of Things (IoT), a Hall sensor readout interface circuit with low offset voltage and low-temperature drift characteristics based on a 180 nm CMOS process is designed in this work. In response to the temperature drift characteristic of the Hall sensor sensitivity, a temperature sensing circuit that is combined with the table lookup method to adjust the gain of the Programmable Gain Amplifier (PGA) is designed, which effectively reduces the Temperature Coefficient (TC) of the Hall sensor. On this basis, the offset voltage of the Hall sensor is greatly eliminated by the use of Correlated Double Sampling (CDS) technology in the main signal channel. The simulation results show that the TC of the Hall sensor is decreased from 966.4 ppm/degrees C to 58.1 ppm/degrees C in the temperature range of -40 degrees C similar to 125 degrees C. The chip measurement results of the main signal channel show that the offset voltage of the Hall sensor is reduced from about 25 mV to about 4 mV and the nonlinear error of the Hall sensor is 0.50%, which occupies an active area of 0.69 mm(2).

Abstract Background The ectoparasite Psoroptes ovis var. cuniculi causes substantial economic losses to the global rabbit industry. Currently, microscopy for identifying Psoroptes mite in skin scrapings, as the “diagnosis gold standard,” remains a challenge owing to its poor sensitivity in detecting low-level and/or early stage mite infestations. Additionally, Psoroptes infestations rapidly trigger cutaneous inflammation, thus the mites might produce some molecules to deal with the harmful effects of inflammation for their long-time survival on the host skin, but these molecules are still mostly unknown. Methods To seek a sensitive diagnostic method and illuminate the new antiinflammatory molecules, we characterized a novel cystatin of P. ovis var. cuniculi (PsoCys) using bioinformatics and molecular biology methods. Results The results showed that PsoCys comprised the classical features of the type II cystatin superfamily including an N-terminal glycine residue, a central QXVXG motif, and a C-terminal LW motif. In mixed stages of mites, the transcription level of PsoCys was significantly higher in “fed” mites than in “starved” mites (P < 0.001), and among the different life-cycle stages of “fed” mites, the expression of PsoCys was higher in adult males than in larva, nymph, and adult females (P < 0.001). The established indirect ELISA based on recombinant PsoCys (rPsoCys-iELISA) presented 95.4% sensitivity and 95.7% specificity. The area under the receiver operating characteristic curve (AUC) for this method was 0.991, indicating its excellent diagnostic performance. Moreover, rPsoCys-iELISA had advantages over microscopy for detecting low-level and/or early stage mite infestations (90% versus 40% in artificial infestation cases at 3 weeks post-infestation; 61.9% versus 22.6% in clinical cases). In addition, rPsoCys could inhibit the activity of papain and cathepsin B in vitro, and significantly suppressed mRNA levels of toll-like receptors (TLR 1, 2, 4, and 6) and downstream molecules (NF-κB, p38, MyD88, IL-10, and IFN-γ) in LPS-stimulated rabbit PBMCs, indicating its anti-inflammatory property. Conclusions Our findings indicated that PsoCys was a novel type II cystatin of Psoroptes mites, and it served as a potential serological diagnostic antigen for detecting low-level and/or early stage mite infestations, as well as a novel anti-inflammatory molecule of Psoroptes mites. Graphical abstract

This paper presents a high-resolution 18-bit SAR ADC with a high 10-bit capacitor DAC and a low 8-bit resistor DAC. The total required number of the unit capacitors is decreased to 512. Foreground digital calibration based on capacitive recombination is introduced to improve linearity. Preamplifiers and output offset storage(OOS) enhance the noise and offset performance of the comparator. As a result, the design under 180 nm process achieves a signal-to-noise and distortion ratio(SNDR) of 105.5dB and a spurious-free dynamic range (SFDR) of 116.3dB under 1 MS/s sampling rate with a single channel. The effective number of bits (ENOB) can reach 17.23 bits with a Nyquist-rate input while consuming 46 mW from a 5 V supply. The resultant Schreier and Walden figures of merit (FoM) are 178.92 dB and 295.34 fJ/conversion-step, respectively. The proposed SAR ADC occupies an actual area of 3850 m by 2810 m.

Rectifiers performance affects the overall efficiency of microwave wireless power transfer systems. The performance of the rectifier device (usually used Schottky diode) determines the upper limit of the rectifier. In order to improve the efficiency and input power of the rectifier, we designed and prepared thin barrier AlGaN/GaN heterojunction rectifier devices. The device achieved 80% conversion efficiency and operates at 5.8 GHz with maximum input power of 28.5 dBm.

This brief presents a fast transient LDO with high power supply rejection ratio (PSRR) over 100-kHz based on adaptive biasing, dynamic biasing technique and a current mode feed-forward amplifier (CMFFA). The dynamic biasing improves the load transient response and the adaptive biasing benefits the loop stability. The CMFFA introduces a left-half-plane zero to compensate for the non-dominant pole without large current consumption. Moreover, a impedance adaptive circuit is also used in this design: it ensures the DC gain and pushes a non-dominant pole to high frequency. Through these methods, the proposed LDO is stable over full load range, from 0mA to 150mA, it achieves fast transient response and high PSRR with a low quiescent current. The LDO is fabricated in a 0.6- mu m CMOS technology. The output voltage can be regulated from 1.8V to 3.3V and the load capacitance is 1 mu F. For a 150mA load step and a 3.3V output voltage, the maximum undershoot voltage is 38.6mV. At maximum load condition, a 41dB PSRR is achieved at 100-kHz and the loop gain bandwidth product is 1.9MHz. The DC gain is around 70dB over the full load range. The measured load regulation and line regulation are 0.06mV/mA and 1mV/V, respectively. The LDO has a minimum quiescent current of 9.6 mu A without load. Finally, the proposed LDO achieves a FOM1 of 16.47ps and a FOM2 of 123.52 mu V.

Based on the low turn-on voltage of GePb-based semiconductor materials, a Schottky diode for low-power microwave power transmission and energy harvesting is present in this paper, and the conversion efficiency of the rectifying circuit based on the SPICE model of this device is significantly improved under low input power, which will provide technological support for the development of the space solar power station, wireless sensor network and other technologies.

This article introduces a bipolar junction transistor (BJT)-based CMOS temperature-to-digital converter (TDC) that demonstrates an accuracy of +/- 1.45 degrees C (3 sigma ) within a temperature range of -55(degrees)C to 125(degrees)C, achieved without the need for calibration. This result is attributed to the implementation of a second-order curvature compensation technique, which utilizes a switched-capacitor integral circuit within the bandgap reference circuit. This approach effectively mitigates higher order reference voltage errors, enhancing overall precision. In addition, this article incorporates dynamic element matching (DEM) and autozeroing techniques, applied in successive amplification stages, to minimize errors originating from current mirror mismatches and operational amplifier offset voltages, respectively. The described BJT-based sensor features a 13-bit successive-approximation-register analog-to-digital converter (SAR ADC), comprising a 5-bit capacitive array and an 8-bit resistor-capacitor hybrid array, designed to monitor and digitally record temperature data. The proposed design operates within a supply voltage range of 2.7-5.5 V and is realized using a 0.6- mu m BJT process, ultimately achieving a resolution of 29.7 mK.

This paper proves that a 2.45 GHz band continuous-wave magnetron has the non-linear response characteristic to the frequency of anode voltage ripple. We deduce the output voltage and frequency expression of a free oscillating magnetron under the influence of high-frequency anode voltage ripple. The output reveals that a magnetron can realize frequency shifting of high-frequency ripple. Sidebands will appear on the both sides of the central frequency of free oscillating magnetron. The frequency difference between sideband and the center is the ripple frequency. Finally, an experimental system is accomplished to testify the theoretical derivation. This research is promised to apply to the simultaneous information and power transfer system based on magnetron.

Objective Plastic optical fibers (POFs) have been widely used in Fiber to the Home (FTTH), automobile optical local area networks (LANs) and fiber-optic sensor fields owing to their large bandwidths, low prices, and easy coupling. POFs exhibit a low loss window in the red band around 650 nm; thus, it is considerably important to use optical waveguide amplifiers to compensate for the propagation loss at a wavelength of 650 nm. Furthermore, optical waveguide amplifiers can be integrated with optical switches, arrayed waveguide gratings, and optical sensors in photonic integrated circuits (PICs) to compensate for optical losses. Research on waveguide amplifiers has often utilized semiconductor lasers as pump sources to excite the intrinsic absorption bands of rare-earth ions. Consequently, the optical power density at the input side of the waveguide can reach approximately 106 W/cm(2) with pumping power of 300 mW at a cross-section of 6 mu m x 5 mu m for the waveguide, which leads to thermal damage in the waveguides and the up-conversion of rare-earth ions. Lanthanide ion complexes with organic ligands exhibit a continuous large absorption band in the blue-violet band, which is suitable for blue-violet light-emitting diode (LED) pumping. The energy absorbed by organic ligands can be effectively utilized to realize the radiative transition of rare-earth ions through intramolecular energy transfer. In addition, the LED pumping method can help improve the thermal stability of waveguides, which is expected to play an important role in optical integrated systems on chips. Methods The absorption spectra of organic ligands, EuCl3 and Eu(DBM)(3)Phen-doped polymethyl methacrylate (PMMA) films, are measured. The fluorescence emission and fluorescence lifetime of the Eu(DBM)(3)Phen-doped PMMA film are characterized. Using an aluminum mask combined with inductively coupled plasma (ICP) etching and one-step photolithography, a ridge waveguide and an evanescent field waveguide are fabricated, respectively. Further, the film-forming properties of the doped film and the morphology of the waveguides are characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The optical field distribution of the signal laser in the waveguides is also simulated. Moreover, using a vertical top pumping mode with a 405 nm LED, the optical gains of the fabricated waveguides are measured at 653 nm. Results and Discussions The organic ligand dibenzoylmethane (DBM) exhibits a broad absorption band ranging from 285 nm to 450 nm; six narrow lines between 379 nm and 591 nm, belonging to the intrinsic absorption of Eu3+ ions from the ground states F-7(0) and F-7(1) to the excited states (5)G(2), L-5(6), D-5(3), D-5(2), D-5(1), and D-5(0), are observed for EuCl3. In the Eu(DBM)(3)Phen complex-doped PMMA film, the broad absorption of the organic ligands is significantly stronger than the intrinsic absorption of the Eu3+ ions (Fig. 1). A schematic of the intramolecular energy transfer and intrinsic absorption and emission of Eu3+ ions is presented (Fig. 2), based on the absorption and fluorescence emission of the doped film; the measured fluorescence lifetime of the D-5(0) level of Eu3+ ions in the PMMA host is 403 p.s (Fig. 3). A ridge waveguide with a cross-section of 12 mu m x 5 mu m can limit 93% of the signal laser and 95% of the pump light in the core layer. In the evanescent field waveguide with a cross-section of 4 mu m x 5 mu m, the limitations in the core layer are 87% and 92% for the signal and pump light, respectively, owing to the smaller refractive index difference (Fig. 6). When pumping with the 405 nm LED, the relative gain in the ridge waveguide with a length of 1. 5 cm increases from approximately 0.2 dB/cm to 1.9 dB/cm at 653 nm, as the pump power increases from 225 mW to 420 mW. For the evanescent field waveguide, a maximum gain of 1.5 dB/cm is obtained on a 2.0 cm-long waveguide under the excitation of the 420 mW 405 nm LED (Fig. 8); this demonstrates the possibility of the practical application of the evanescent-wave coupling method in PICs. Conclusions In this study, the europium complex Eu(DBM)(3)Phen is doped into a PMMA polymer as an active material to fabricate two types of polymer waveguide amplifiers-a ridge waveguide and an evanescent field waveguide-using an aluminum mask combined with ICP etching and one-step photolithography, respectively. Under the excitation of a 405 nm blue-violet LED, relative gains of 1. 9 dB/cm and 1. 5 dB/cm are obtained at 653 nm, respectively, for these waveguides. The UV absorption and fluorescence emission of the Eu(DBM)(3)Phen-doped PMMA film are also characterized. The results show that the intramolecular energy transfer of organic ligands can realize the transition of Eu3+ ions from the D-5(0) energy level to the F-7(3) energy level under LED pumping. The relatively long fluorescence lifetime of the D-5(0) level of Eu3+ ions can facilitate high gains in optical amplifier systems.

Emerging neural reconstruction techniques based on tomography (e.g., NeRF, NeAT, and NeRP) have started showing unique capabilities in medical imaging. In this work, we present a novel Polychromatic neural representation (Polyner) to tackle the challenging problem of CT imaging when metallic implants exist within the human body. CT metal artifacts arise from the drastic variation of metal's attenuation coefficients at various energy levels of the X-ray spectrum, leading to a nonlinear metal effect in CT measurements. Recovering CT images from metal-affected measurements hence poses a complicated nonlinear inverse problem where empirical models adopted in previous metal artifact reduction (MAR) approaches lead to signal loss and strongly aliased reconstructions. Polyner instead models the MAR problem from a nonlinear inverse problem perspective. Specifically, we first derive a polychromatic forward model to accurately simulate the nonlinear CT acquisition process. Then, we incorporate our forward model into the implicit neural representation to accomplish reconstruction. Lastly, we adopt a regularizer to preserve the physical properties of the CT images across different energy levels while effectively constraining the solution space. Our Polyner is an unsupervised method and does not require any external training data. Experimenting with multiple datasets shows that our Polyner achieves comparable or better performance than supervised methods on in-domain datasets while demonstrating significant performance improvements on out-of-domain datasets. To the best of our knowledge, our Polyner is the first unsupervised MAR method that outperforms its supervised counterparts. The code for this work is available at: https://github.com/iwuqing/Polyner.

为了提高具有多径效应的无线功率传输中接收系统效率,提出并设计了一款工作在5.7～5.9 GHz频段的4×4小型化L槽能量收集超表面.该超表面与传统的整流天线相比,具有广入射角度和极化不敏感特性.研究分析了不同入射角下超表面的能量收集效率,仿真表明超表面在5.8 GHz、入射角为0°时具有99.3％的吸波效率,91.3％的收集效率.实验过程中入射角在0°～40°的范围内保持50％以上的收集效率.超表面阵列尺寸为8.64 cmX8.64 cmX0.762 cm.

为了降低微波无线能传输系统(MWPT)整流电路模块的能量损耗,使用AlGaN/GaN异质结肖特基二极管(SBD)可以有效地降低整流损耗.本文设计了一种高性能多通道SBD结构,其具有四个周期性重复AlGaN/GaN的异质结构.为了提高器件的反向特性,使用T型阳极和对不同的AlGaN势垒层采用不同掺杂浓度的方式.这种独特的多通道器件结构正向特性有了显著提升,导通电阻降低了 74％,达到了 2Ω·mm,导通电压降低了 57％,达到了 0.31 V.由于T型阳极和独特的Si掺杂方式,该结构的击穿电压达到了 300 V.