Search Results (920)

The proliferation of IoT using heterogeneous wireless technologies within the unlicensed spectrum has intensified cross-technology interference (CTI) in wireless local area networks (WLANs). As WLANs increasingly adopt time-triggered transmission methods to support real-time services, this interference affects throughput, packet loss, and latency. This paper presents a CTI-aware rate adaptation framework designed to mitigate interference in WLANs without direct coordination with heterogeneous wireless devices. The framework includes a CTI identification model and CTI-aware rate selection algorithms. Leveraging short-time Fourier transform, the identification model captures the time–frequency–power characteristics of CTI signals, enabling the estimation of the average power of various heterogeneous wireless technologies employed by interfering devices. The rate selection algorithms predict CTI occurrence times and adjust the transmission rate accordingly, enhancing the performance of existing explicit and implicit interference mitigation methods. Experimental results demonstrated that the lightweight CTI identification model accurately estimated the average power of each type with an error margin of ±1.414 dBm, achieving this in under 1 ms on the target hardware. Additionally, applying the proposed framework to explicit interference mitigation enhanced goodput by 20.67%, reduced packet error rate by 2.38%, and decreased the probability of packets exceeding 1 ms latency by 0.932% compared to conventional methods. Full article

This paper proposes a terminal matching network (TMN) technology, which can realize wideband matching of microwave rectifiers in a wide input power range. At the same time, it is proposed to realize ultra-wideband microwave rectifiers by connecting two TMN branches of different frequencies in parallel. In order to verify this theory, two rectifiers using single TMN and dual TMN branches are designed and realized based on high-power GaN Schottky barrier diodes (SBDs). The single TMN GaN rectifier achieves a peak efficiency of 72.3% and a conversion efficiency of more than 70% in the frequency range of 1.8–2.7 GHz at 1 W of input power, while being more than 50% efficient in the input power range of 16–35 dBm. Benefitting from the power combination of different frequency TMNs, the dual TMNs GaN rectifier achieves 75.8% peak efficiency and over 70% conversion efficiency at 1.1–3.1 GHz frequency and 1 W input power with a relative bandwidth over 95.2% and maintains high efficiency of over 50% in the input power range of 15–35 dBm. The advantages of the ultra-wideband, wide input power range, high power, and high efficiency make the GaN rectifier with TMNs expected to play an important role in microwave power transmission (MPT). Full article

The efficiency of organic solar cells (OSCs) is influenced by various factors, among which environmental temperature plays a significant role. Previous studies have shown that the thermal stability of these cells can be enhanced by incorporating a third component into their structure. Ternary organic solar cells, particularly, have shown promising results in improving thermal stability. A well-designed electron transport layer (ETL) can significantly bolster thermal stability by facilitating efficient charge transport and reducing charge recombination. In this study, we investigated the effect of temperature, ranging from 300 K to 400 K, on the efficiency of inverted ternary structures by using a one-dimension optoelectronic model on “Oghma-Nano 8.0.034” software. The structures examined include (S1) “FTO/SnO₂/PM6:D18:L8-BO/PEDOT: PSS/Ag”, (S2): “FTO/C₆₀/PM6:D18:L8-BO/PEDOT: PSS/Ag”, and (S3): “FTO/PC₆₀BM/PM6:D18:L8-BO/PEDOT: PSS/Ag”. Simulations using three different ETLs—SnO₂, C₆₀, and PC₆₀BM—at 340 K (66.85 °C) resulted in a main effect on open circuit voltage (V_oc) and fill factor (FF) values, in addition to an important J_sc value in terms of thermally stable devices. However, these structures retained 92% of their initial ~20% efficiency observed at 300 K, demonstrating significant thermal stability under high power conversion efficiency (PCE) conditions. Full article

This paper proposes and designs a silicon-based negative capacitance field effect transistor (NCFET) to replace conventional MOSFETs as the rectifying device in RF-DC circuits, aiming to enhance the rectification efficiency under low-power density conditions. By combining theoretical analysis with device simulations, the impacts of the ferroelectric material anisotropy, ferroelectric layer thickness, and active region doping concentration on the device performance were systematically optimized. The proposed NCFET structure is tailored for microwave wireless power transmission applications. Based on the optimized NCFET, a half-wave rectifier circuit employing a novel diode connection configuration was constructed and verified through transient simulations. The results show that at a microwave frequency of 2.45 GHz, the designed NCFET rectifier achieves rectification efficiencies of 16.1% and 29.75% at input power densities of −10 dBm and −6 dBm, respectively, which are 7.15 and 2.3 times higher than those of conventional silicon-based MOS devices. Furthermore, it significantly outperforms CMOS rectifiers reported in the literature. This study demonstrates the superior rectification performance of the proposed NCFET under low-power density conditions, offering an efficient device solution for microwave wireless power transmission systems. Full article

An analytical method is introduced to assess the susceptibility of radio altimeter (RA) receivers to adjacent-band fifth-generation (5G) signal interference and to quantify its impact on RA performance. The power-series method is employed to analyze the intermediate frequency (IF) signal gain compression effect of 5G signal interference on RA receivers. A behavioral-level simulation model of the RA receiver’s radio frequency (RF) front-end is constructed based on the advanced design system (ADS), and a 5G signal injection simulation is performed. The simulation results indicate that 5G signals can induce nonlinear effects in the RF front-end circuit of the RA, leading to IF signal gain compression, thereby affecting the subsequent signal processing of RA receivers. The interference effect on the RA receiver is influenced by factors such as the power and frequency of the 5G interference signal. To investigate this, an interference injection test was conducted on a specific RA receiver to validate the aforementioned interference mechanisms. The test results indicate that when the average power of the injected 5G signal at a frequency of 4000 MHz reaches −16 dBm, the IF signal power is significantly reduced. As the power of the 5G signal increases, this nonlinear effect becomes more pronounced. Furthermore, the height error ratio significantly increases, with consistent trends observed across different test frequencies. The interference threshold for the RA is lower when the signal frequency is closer to the RA operational signal frequency. Our research results demonstrate the efficacy of this method, providing a reference basis for studies on interference mechanisms and the evaluation of interference effects related to RA receivers within the electromagnetic environment of 5G signals. Full article

The 5G frequency band is extremely close to the operating frequency band of radio altimeters (RAs), so an in-depth study of the possible interference of 5G’s key parameters on RAs is especially necessary to ensure aviation safety. In this paper, the interference magnitude of 5G waveforms on an altimeter was measured by simulating the Adjacent Channel Leakage Power Ratio (ACLR) values for different sub-carrier spacing (SCS) and channel bandwidth configurations. Furthermore, interference injection experiments on simulated 5G signals and the interference thresholds of a frequency-modulated continuous wave (FMCW) altimeter were compared to experiments on the effects of the different configurations of 5G SCSs, channel bandwidths, and center frequency points. The interference thresholds of this FMCW altimeter were found to be in the range of 1 dBm to 6 dBm and −4 dBm to 0 dBm under the interference of 5G signals at the center frequency points of 3.7 GHz and 3.9 GHz. These results provided a certain reference for the engineering judgement margin of the interference thresholds. Full article

Bacterial and eukaryotic dihydrofolate reductase (DHFR) enzymes are essential for DNA synthesis and are differentially sensitive to the competitive inhibitors trimethoprim and methotrexate. Unexpectedly, trimethoprim did not reduce Wolbachia abundance, and the wStri DHFR homolog contained amino acid substitutions associated with trimethoprim resistance in E. coli. A phylogenetic tree showed good association of DHFR protein sequences with supergroup A and B assignments. In contrast, DHFR is not encoded by wFol (supergroup E) and wBm (supergroup D) or by genomes of the closely related genera Anaplasma, Ehrlichia, Neorickettsia, and possibly Orientia. In E. coli and humans, DHFR participates in a coupled reactions with the conventional thymidylate synthase (TS) encoded by thyA to produce the dTMP required for DNA synthesis. In contrast, Wolbachia and other Rickettsiales express the unconventional FAD-TS enzyme encoded by thyX, even when folA is present. The exclusive use of FAD-TS suggests that Wolbachia DHFR provides a supplementary rather than an essential function for de novo synthesis of dTMP, possibly reflecting the relative availability of, and competing demands for, FAD and NAD coenzymes in the diverse intracellular environments of its hosts. Whether encoded by thyA or thyX, TS produces dTMP by transferring a methyl group from methylene tetrahydrofolate to dUMP. In the Rickettsiales, serine hydroxymethyltransferase (SMHT), encoded by a conserved glyA gene, regenerates methylene tetrahydrofolate. Unlike thyA, thyX lacks a human counterpart and thus provides a potential target for the treatment of infections caused by pathogenic members of the Rickettsiales. Full article

Wireless sensor networks often rely on battery power, which incurs high costs, considerable volume, and a limited lifespan. Additionally, the communication range of existing passive sensor tags remains short, which challenges their suitability for evolving Internet of Things (IoT) applications. This paper, therefore, presents a long-distance passive RFID sensing tag that integrates multi-source energy harvesting and reflection amplification. Multi-source energy harvesting enhances tag receiving sensitivity and extends the system’s downlink communication distance, while reflection amplification increases tag reflection power and improves the uplink communication distance, thereby significantly expanding the overall communication range. The test results show that the tag achieves a receiving sensitivity of −45 dBm, a reflection gain of 44 dB, and a communication distance of up to 96 m. Full article

This paper uses the non-integer ratio coaxial line impedance transform matching method to design a wideband RF power amplifier. The motivation for the research stems from the limitations of the fixed conversion ratio of traditional impedance converters at RF frequencies and the challenges of low-frequency performance degradation. A fixed conversion ratio and low-frequency performance often limit traditional impedance matching methods. The model enables flexible and efficient wideband impedance matching, covering a wide frequency range of 2–650 MHz. The results show that the power amplifier has an output power of more than 48.5 dBm, a gain of more than 16 dB, and a drain efficiency (DE) of more than 55% in the frequency band range of 2–650 MHz, which is superior to similar designs in terms of low-frequency performance and bandwidth. Full article

Reconfigurable Intelligent Surface (RIS) technology relies on its reconfigurable electromagnetic properties and offers an efficient solution for enhancing signal quality in coal mine communications. RIS technology significantly enhances signal coverage and transmission quality in complex, confined environments. This paper proposes a channel propagation optimization scheme for coal mine RIS communication systems, using the Deep Deterministic Policy Gradient (DDPG) algorithm. By jointly optimizing base station power allocation and RIS phase shift, this paper comparatively analyzes RIS reflection performance under ideal and non-ideal conditions, focusing on its impact on system propagation rates. A comparison of system stability and convergence rates among the DDPG, A3C, and DQN algorithms reveals that, under the DDPG optimization scheme, the average link rate reaches 6.6 bps/Hz with ideal RIS reflection and 4.6 bps/Hz with non-ideal conditions when the base station transmit power is defined as 38 dBm. Furthermore, increasing the number of RIS units from 8 to 32 results in a system link rate improvement from 5 bps/Hz to 6.8 bps/Hz. The research results provide new design ideas for optimizing coal mine RIS communication systems and open up new solutions for the use of artificial intelligence in complex coal mine tunnel environments. Full article

We propose a double-sided layout design method with high reliability for multi-beam phased array transmitter modules based on high-temperature co-fired ceramic technology. Efficient transmission of microwave signals and low-frequency signals is realized by using multi-layer wiring and an inter-layer transition. The proposed Ka-band transmitter module exhibits a gain of ≥26 dB, an output power of ≥21 dBm, and an overall efficiency of the component of ≥40%. The RMS accuracy of phase shift and attenuation is better than 3° and 0.5 dB, respectively. The proposed design method addresses the problems of high integration, lightness, and miniaturization in transmit/receive module design, and shows a good performance of heat dissipation performance and sealing capability. It can be easily expanded to large-scale phased arrays. Full article

The N-methyl-D-aspartate (NMDA) glutamate receptor is a major target of ethanol, and it is implicated in learning and memory formation, and other cognitive functions. Glycine acts as a co-agonist for this receptor. We examined whether Org24598, a selective inhibitor of glycine transporter1 (GlyT1), affects ethanol withdrawal-induced deficits in recognition memory (Novel Object Recognition (NOR) task) and spatial memory (Barnes Maze (BM) task) in rats, and whether the NMDA receptor glycine site participates in this phenomenon. Male Wistar rats were habituated to NOR or BM tasks, and then received binge-like intragastric ethanol administration (5 days, 5 g/kg). After ethanol withdrawal, Org24598 (0.1, 0.3, and 0.6 mg/kg) was administered 30 min before NOR (day 10 of withdrawal) or the reversal learning phase of BM (day 11–13 of withdrawal) task. The expression of GluN1 and GluN2B subunits of NMDA receptors were measured in the perirhinal cortex (PRC) and hippocampus (HIP) after termination of NOR. In the BM task, a glycine antagonist, L-701,324 (5 mg/kg), was administered 30 min before Org24598 to confirm the involvement of the NMDA receptor glycine site in the effects of Org24598. Our study showed that binge-like ethanol administration induced recognition and spatial memory impairments after withdrawal in rats. Additionally, an up-regulation of GluN1 and GluN2B subunits of the NMDA receptor was observed in the HIP and PRC on day 11 of abstinence. Org24598 ameliorated memory loss and normalized the expression of these subunits. L-701,324 reversed the effect of Org24598. Thus, NMDA receptor glycine sites are important in ethanol withdrawal-induced memory impairments. Full article

As data center interconnects surge towards a 1.6 Tbit/s data rate, achieving cost-effective and technically viable solutions present challenges. Intensity-modulation and direct-detection (IM/DD) transmission over O-Band using standard single-mode fiber has emerged as a promising low-cost option. However, understanding the limitations imposed by factors like chromatic dispersion (CD) and fiber non-linearity (FWM) is crucial, particularly in different scenarios, such as operating at 8 × 100 GBaud PAM4 in an LWDM-8 configuration. In this paper, we adopt a statistical approach to assess outage probability and consider practical fluctuations in link parameters. Numerical modeling suggests IM/DD can span distances up to 5 km with transmission power under 0 dBm using this architecture. In addition, we evaluate recently proposed architecture to achieve 800 Gbit/s and 1.6 Tbit/s using an LWDM4 configuration and assess the impact of FWM to understand the role of zero-dispersion wavelength (ZDW) of the fiber. Coherent transmission leverages more powerful signal processing capabilities which extends the transmission range. Yet, reducing coherent transmission complexity is desirable for cost-effective and power-efficient data center applications. By exploring dual wavelength transmission and DP-16 QAM transceivers, akin to IM/DD counterparts, the feasibility of streamlining this architecture is also studied. The analysis indicates that the complexity of the coherent approach can be reduced without significant penalties for distances up to 10 km. Full article

In fiber optic communication systems, the dispersion and nonlinear interaction of optical signals are critical to modeling fiber optic communication, and the regular perturbation (RP) model is a simplified modeling method composed of parallel branches, which has obvious advantages in deep learning backpropagation. In this paper, we propose a simplified single-mode fiber signal transmission model based on the RP model, which significantly improves the fitting accuracy of the model for dispersion and nonlinear interactions at the same complexity by adding trainable parameters to the standard RP model. We explain in the paper that this improvement is applicable to dual-polarization systems and still effective under the conditions of large launch power, without dispersion management, and containing amplified spontaneous emission (ASE) noise. The model uses the standard split-step Fourier method (SSFM) to generate labels and updates parameters through gradient descent method. When transmitting a dual-polarization signal with a launch power of 13 dBm, the modified regular perturbation (MRP) model proposed in the paper can reduce the fitting errors by more than 75% compared to the standard RP model after transmitting through a 120 km standard single-mode fiber. Full article

Percutaneous Coronary Intervention (PCI) is a treatment method that involves reopening narrowed arteries with a balloon catheter that delivers a cylindrical, mesh-shaped implant device to the site of the stenosis. Currently, by applying a coating to a bare metal stent (BMS) surface to improve biocompatibility, the main risks after PCI, such as restenosis and thrombosis, are reduced while maintaining the basic requirements for the mechanical behavior of the stent itself. In this work, for the first time, the development and optimization process of the spatial structure of the Co-Cr stent (L-605) with a graphene-based coating using cold-wall chemical vapor deposition (CW-CVD) to ensure uniform coverage of the implant was attempted. The CW-CVD process allows the coating of 3D structures, minimizing thermal stress on the surrounding equipment and allowing the deposition of coatings on temperature-sensitive materials. It produces uniform and high-purity films with control over the thickness and composition. The reduced heating of the chamber walls minimizes unwanted reactions, leading to fewer impurities in the final coating. The graphene layers obtained using Raman spectroscopy at different parameters of the CW-CVD process were verified, their properties were investigated, and the functional mechanical behavior of the studied graphene-covered stent was confirmed. In vitro, graphene-coated stents promoted rapid endothelial cell repopulation, an advantage over gold-standard drug-eluting stents delaying re-endothelialization. Also, full-range biocompatibility studies on potential allergic, irritation, toxicological, and pyrogenic reactions of new material in vivo on small animal models demonstrated excellent biocompatibility of the graphene-coated stents. Full article