Wireless Transmission Research Articles

Symmetry engineering in 2D bioelectronics facilitating augmented biosensing interfaces

Symmetry lies at the heart of two-dimensional (2D) bioelectronics, determining material properties at the fundamental level. Breaking the symmetry allows emergent functionalities and effects. However, symmetry modulation in 2D bioelectronics and the resultant applications have been largely overlooked. Here, we devise an oxidized architectural MXene, referred to as oxidized MXene (OXene), that couples orbit symmetric breaking with inverse symmetric breaking to entitle the optimized interfacial impedance and Schottky-induced piezoelectric effects. The resulting OXene validates applications ranging from microelectrode arrays, gait analysis, active transistor matrix, and wireless signaling transmission, which enables high-fidelity signal transmission and reconfigurable logic gates. Furthermore, OXene interfaces were investigated in both rodent and porcine myocardium, featuring high-quality and spatiotemporally resolved physiological recordings, while accurate differentiated predictions, enabled via various machine learning pipelines.

Demonstration of 400 Gbit/s/λ wireless transmission for a photonic-assisted SISO integration system at 220 GHz

We experimentally demonstrate a dual-polarized, single-input single-output (SISO) photonic-electronic integrated system, achieving a single-wavelength data rate of 400 Gbit/s at 220 GHz. This system is based on a self-developed IQ mixer, orthomode transducers (OMTs), and a dual-polarized multiplexing antenna (DPMA). The IQ mixer front-end exhibits a conversion loss of over 14 dB within a 30 GHz bandwidth, and cross talk between IQ channels is better than 15 dB for most frequency points. The OMT achieves a polarization isolation of over 30 dB and an insertion loss (IL) of less than 3 dB across the entire WR-4 band (170–260 GHz). The DPMA operates in the WR-4 band, with measured in-band return loss characteristics better than 15 dB. The 50 GBaud DP-16QAM modulation is successfully transmitted over a 20 km SSMF and a 1 m wireless link. Additionally, a 125 Gbit/s real-time transparent fiber-THz-fiber SISO transmission system is demonstrated, marking a significant advancement in the development of large-bandwidth, high-speed 6G photonic-electronic systems.

Machine learning-based models for forecasting radio refractivity over the coastal area of South Africa

Surface refractivity is a crucial parameter that determines the bending of radio signals as they propagate within the troposphere. It is greatly influenced by the atmospheric weather conditions and changes rapidly, especially in the coastal areas. This research utilized 50 years (1974-2023) surface temperature, pressure, and humidity data from six coastal stations in South Africa to forecast radio refractivity in the Mediterranean climate. Five machine learning models: Gated Recurrent Unit (GRU), Light Gradient Boosting Machine (LightGBM), Long-Short Term Memory (LSTM), Prophet, and Random Forest were trained for future prediction of surface refractivity at any coastal area in South Africa. The stations latitude, longitude, altitude, surface refractivity and date were applied as the input parameters to train the models. The models were optimized through the randomized searchCV hyperparameter tuning to improve their efficiency. The LightGBM outperformed other models with RMSE and adjusted determination coefficients of 1.67 and 0.96, respectively. The model is recommended for future prediction of surface refractivity needed for the improvement of point-to-point wireless communication, terrestrial radio and television transmissions, and mobile communication networks in the coastal sub-tropical regions.

Holocaust in Alytus County in 1941

Like other counties in Lithuania, the persecution and extermination of Jews in Alytus county can be divided into two phases. The first (the end of June–mid-July 1941) was dominated by political motives of persecution. Jews were often arrested, imprisoned, and shot to death, as were other former Communists, members of Komsomol, Soviet government officials or supporters. People of non- Jewish nationality (Lithuanians, Russians, Poles) were also persecuted for the same reason. The surviving lists of people detained and wanted by police show that in the first weeks of the Nazi occupation, the majority of people arrested in Alytus county because of pro-Soviet activities were, however, of Lithuanian ethnicity. What is particular about Alytus county is the more intense and wider persecution of Communists and Soviet activists than in other counties in Lithuania. By mid July 1941, 82 people in this category were shot in Alytus county under orders of the German military authority. Specific discriminatory measures applicable only to Jews included marking of the Jews (by making them wear the compulsory Star of David), prohibition to perform their religious rites publicly, provision of smaller food rations, prohibition to buy food products, and seizure of radio transmitters, motorcycles and bicycles. In the first phase, no massive or total Jewish genocide was enforced – women, children and old people were usually not arrested or shot. In the second phase (mid-July–mid-September 1941) the Jewish situation deteriorated. In the centres of rural districts where the numbers in the Jewish communities were large (for example, in Butrimonys), ghettos were set up and all Jews of the area were driven into the ghettos. This was when they started sending the detained groups of Jews to Alytus to be shot. In the middle of August 1941, the number of massacres of Jews increased considerably and by mid-September 1941, almost all of the Jews of Alytus county had been killed (except for the Jews of the Marcinkonys ghetto who were killed in November 1942 and individual Jews who managed to hide before shooting). On the basis of documents dated 1941, at least 6,165 Jews were murdered. Most of those who carried out the massacres were members of Obersturmführer Joachim Hamann’s ‘flying squad’ from Kaunas, local policemen and members of the auxiliary police, the so-called baltaraiščiai (they wore white armbands). More valuable items of Jewish property (golden jewellery, clocks, etc.) were appropriated by various German authorities, some of the property was appropriated by participants in the massacre, and what was left was sold to local inhabitants.

Impact of coil envelope on the coupling coefficient in magnetic induction wireless power transmission systems

Abstract In recent years, research in the field of wireless power transmission by magnetic induction has increased due to the diversity of applications, such as medicine, electronics, and transport, which require this technology. However, despite its maturity to date, this technology has had difficulty gaining acceptance due to the short transmission distance and low coupling coefficient between the transmitting and receiving coils. Generally, these coils need to be protected by an envelope. However, the impact of the nature of the envelope on the coupling coefficient has not studied. This work focuses on the impact of the nature of the coil protection envelope on the coupling coefficient. Three-dimensional flat spiral coils and the protective envelope are modelled and subjected to parametric analysis with variable air gaps and frequencies using ANSYS-Electronics Maxwell 2022 R1 software with the finite element method (FEM). Simulation results show that a coil protected by an insulating envelope has a higher coupling coefficient compared to one protected by a conducting material. It is also shown that the coupling coefficient decreases as the operating frequencies increases. The ohmic losses in coils protected by an insulating envelope are greater than those in coils protected by a conductive material.

Design and implementation of wireless power transfer device

Abstract. Magnetic coupled resonant radio energy transmission (WPT) technology utilizes the coupling of the magnetic fields of the transmitting and receiving coils and wirelessly transmits energy through electromagnetic induction, greatly expanding the applications of power equipment in special environments. The technology uses the magnetic field coupling between the transmitting coil and the receiving coil to realize the wireless transmission of energy through electromagnetic induction. This method breaks the limitation of traditional wire transmission and greatly expands the application potential of power equipment in various special environments. In this paper, an efficient, stable and long-distance wireless charging device is designed and realized. In order to improve transmission efficiency, two-coil configuration with series-series structure is adopted, and its equivalent circuit model is established by circuit theory and Kirchhoff's law. Therefore, a new radio energy transmission device based on single chip microcomputer is designed, including PWM signal generator, level matching circuit, high frequency inverter circuit and other key parts. Expressions for transmission efficiency and output power are derived from equation analysis and power-on experiments performed on a physical device. In addition, the effects of transmission frequency, load impedance and transmission distance on the performance are investigated.

Research on the Technology and Application of Remote Wireless Transmission of Digital Image Signal

Abstract. With the increasing demand for remote real-time high-quality video transmission, especially in the context of large area applications of unmanned aerial vehicle (UAV) and remote location instant live broadcast, traditional wired transmission methods have been surpassed by digital transmission methods due to their superior performance in image quality, transmission distance and delay. Therefore, this study focuses on the application of digital image wireless transmission in remote scenarios such as UAVs, including key digital transmission technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Coded Orthogonal Frequency Division Multiplexing (COFDM), as well as public network link communication technologies such as 4G and 5G, by means of a literature study and a case study. It also analyzes the development of WiFi, Lightbridge and OcuSync graphics transmission systems using DJI brand products as case studies. The analysis shows that digital image wireless transmission, especially COFDM and advanced proprietary systems such as DJI's OcuSync, has significant advantages in terms of transmission distance, interference immunity, encryption techniques, and reusability. However, factors such as building obstruction, frequency interference, and weather conditions can affect the transmission quality. To mitigate these challenges, solutions are proposed, such as auxiliary signal enhancement systems, adaptive frequency hopping and software-defined radio technologies.

60-GHz Millimeter-Wave over Visible Light Communications for Downlink Wireless Networks

Background and Objective: In this paper, we address potential solution for downlink wireless communications by integrating visible light communications (VLC) with the broadband radio frequency (RF) networks operating at 60 GHz-millimeter wave (mmWave) band. For this hybrid design, the outdoor 60 GHz-mmWave based RF link is utilized to ensure backhaul connectivity for VLC indoor system, while the VLC exploiting the lighting infrastructure that essentially used LEDs as optical source to provide low-cost and high-speed data access. Methods: The hybrid 60 GHz-mmWave/VLC system is analyzed by using 16-QAM OFDM signal, and its performance is investigated by evaluating the signal to noise ratio (SNR) and the received signal power distributions, for regular placement of LEDs and random location of receivers within the room. The impact of the transmitter-receiver parameters, and their orientations and directivities are also considered. Results: Numerical results show the efficiency of the proposed system, which can retransmit RF signals at 60 GHz-mmWave band using visible optical carriers in the indoor environment. Conclusion: The results suggest that the hybrid 60 GHz-mmWave/VLC system is able to provide reliable wireless data transmission, making it an attractive solution for downlink indoor communications.

Race and Privacy in Broadcast Police Communications

Radios are essential for the operations of modern police departments, and they function as both a collaborative communication technology and a sociotechnical system. However, little prior research has examined their usage or their connections to individual privacy and the role of race in policing, two growing topics of concern in the US. As a case study, we examine the Chicago Police Department's (CPD's) use of broadcast police communications (BPC) to coordinate the activity of law enforcement officers (LEOs) in the city. From a recently assembled archive of 80,775 hours of BPC associated with CPD operations, we analyze human-generated text transcripts of radio transmissions broadcast 9:00 AM to 5:00 PM on August 10th, 2018 in one majority Black, one majority White, and one majority Hispanic area of the city (24 hours of audio) to explore four research questions: (1) Do BPC reflect reported racial disparities in policing? (2) How and when is gender, race/ethnicity, and age mentioned in BPC? (3) To what extent do BPC include sensitive information, and who is put at most risk by this practice? (4) To what extent can large language models (LLMs) heighten this risk? We explore the vocabulary and speech acts used by police in BPC, comparing mentions of personal characteristics to local demographics, the personal information shared over BPC, and the privacy concerns that it poses. Analysis indicates (a) policing professionals in the city of Chicago exhibit disproportionate attention to Black members of the public regardless of context, (b) sociodemographic characteristics like gender, race/ethnicity, and age are primarily mentioned in BPC about event information, and (c) disproportionate attention introduces disproportionate privacy risks for Black members of the public. This study shows BPC can provide a novel window into disproportionate attention (i.e., via radio communications) by law enforcement officers to specific racial groups, leading to increased privacy vulnerability for those groups, particularly Black males.

Tunable Negative Permittivity and Magnetic Properties of Ag/BLM Ceramic Metacomposites

Abstract Percolation composites with tunable negative permittivity have garnered significant attention due to their potential use in the field of electromagnetic interference shielding, near field amplification, antennas, and sensors. However, studies on the magnetic property at a frequency range of 100 MHz to 1 GHz are relatively scarce. The objective of this study was to examine the magnetic property and adjustable negative permittivity of silver/La-doped barium ferrite(Ag/BLM) ceramic metacomposites. In this study, Ag/BLM ceramic metacomposites with varying Ag content were prepared using a simple impregnation-calcination method. We investigate the permittivity, reactance, and permeability of Ag/BLM ceramic metacomposites at 100 MHz ~ 1GHz. The findings indicate that the percolation threshold for Ag/BLM ceramic metacomposites with x wt% is between 10 wt% and 19 wt%. When Ag content reaches 19 wt%, it creates a conductive network that generates a high number of free electrons. This leads to low-frequency plasma states and results in negative permittivity. Meanwhile, the permeability of Ag/BLM ceramic metacomposites shows the frequency dispersion due to the magnetic resonance and eddy current. Therefore, this study's findings suggest that composites with tunable negative permittivity and permeability may be developed and utilised for microwave absorption, antenna design, and wireless power transmission.

An Optimized Multi-Level Control Method for Wireless Power Transfer System Using the Particle Swarm Optimization Algorithm

A Wireless Power Transfer (WPT) system, known for its contactless power delivery, is extensively used for power supply in spacecraft applications. Achieving efficient and stable power transfer necessitates the integration of DC/DC converters on both the primary and secondary sides of WPT systems for power conversion and control. Traditional efficiency optimization methods primarily focus on impedance matching within the wireless power resonance network, often neglecting the overall efficiency optimization of multi-stage DC-DC and WPT systems. This oversight results in suboptimal overall system efficiency despite optimal efficiency in the wireless transmission segment. Additionally, the time-varying nature of mutual inductance and load parameters during power transmission in WPT systems presents challenges for maximum efficiency tracking and power control. This paper introduces a multi-level coordinated control efficiency optimization method for WPT systems utilizing the particle swarm optimization (PSO) algorithm. This method takes into account the transmission losses across all power conversion units within the WPT system, establishing a mathematical model for the joint optimization of overall system transmission efficiency and power. The PSO algorithm is then employed to solve this optimization model using estimated mutual inductance and load values. By adjusting the DC/DC converters on both sides, the method ensures optimal overall system efficiency and consistent power transmission. Experimental results indicate that under varying load and mutual inductance conditions, a Series–Series (SS) compensated WPT system using this method achieves a 200 W power output with maximum efficiency tracking, a power output error of 0.63%, and an average transmission efficiency of 86.2%. This demonstrates superior power transmission stability and higher efficiency compared to traditional impedance matching methods.

Multi-resonance-cavity hydrophone for underwater acoustic data transmission

Transmitting data from the seabed platform to relay buoys using wireless transmission techniques is becoming the main approach for seabed platform data retrieval, and data transmission via underwater acoustic waves offers certain advantages compared to that via underwater optical or electromagnetic waves. Hydrophones play a crucial role in underwater acoustic transmission, and low-cost, miniaturized, high-sensitive hydrophones based on resonance cavity meet the demands of seabed platform data retrieval scenarios. This paper proposes a multi-resonance-cavity hydrophone for underwater acoustic data transmission. The acoustic resonance characteristics of the cavity is studied through theoretical analysis and simulations. An eight-layer spherical cavity hydrophone is designed and fabricated, and the acoustic sensing characteristics and performances of the hydrophone are simulated and tested. Finally, underwater acoustic data receiving tests using the proposed hydrophone are conducted in a lake, demonstrating the hydrophone’s ability to accurately receive acoustic data at the baud rate of 145.45 bps with no error.

Computational Complexity for Simplified Universal Filtered Multi-Carrier (UFMC) Wireless Transmitter

Computational Complexity for Simplified Universal Filtered Multi-Carrier (UFMC) Wireless Transmitter

A Wearable Electrochemical Sensor Based on Single-Atom Pt Anchored on Activated NiCo-LDH/Ti3C2Tx for Real-Time Monitoring of Glucose.

Wearable, noninvasive sweat sensors enable real-time monitoring of metabolites in human health management. However, the commercial enzyme-based and currently nonenzymatic glucose sensor represents sluggish glucose oxidation kinetics and a narrow sensing range. Rational design of sensitive materials is significant yet faces a huge challenge. Herein, we construct a single-atom Pt supported on NiCo-LDH/Ti3C2Tx heterostructures (Pt1-NiCo-LDH/Ti3C2Tx) as the nonenzymatic electrochemical glucose sensor sensitive materials for selective detection of glucose level in human sweat. The obtained Pt1-NiCo-LDH/Ti3C2Tx with improved structural stability and enhanced charge transfer efficiency shows a low oxidation peak potential of 0.49 V, high sensitivity of 506.6 μA mM-1 cm-2, a low detection limit of 0.035 μM, and long-term stability toward the glucose detection. The wearable sensor, coupled with a wireless transmission module and a signal processing chip, is used for real-time perspiration glucose monitoring during outdoor exercise. The result is comparable to that of high-performance liquid chromatography (HPLC). This research provides a new paradigm for designing a wearable nonenzymatic electrochemical glucose sensor, enabling noninvasive real-time monitoring of glucose concentrations in human sweat.

Structure optimization of transmission coil of wireless power transmission system for rail transit vehicles

Abstract To solve the transmission efficiency problem of traditional wireless energy systems applied to rail transit vehicles. In this paper, the key components of a wireless power transmission system, such as the transmission efficiency of the transmission coil and the poor anti-deviation ability of the coil, are studied. Firstly, this paper analyzes the traditional planar circular and square coil shapes, analyzes the magnetic field characteristics of the traditional transmission coil structures by ANSYS Maxwell simulation software, and obtains the advantages and disadvantages of different coil structures. According to the analysis structure, the coil structure is optimized and improved, and the coil structure form of the combined coil is put forward. Through the comparative analysis of finite element simulation software, it is attested that combined coil structure has a significant improvement in transmission efficiency and anti-deviation ability.

A fully integrated wireless microfluidic immunosensing system for portable monitoring of Staphylococcus aureus

The advanced devices that function fully without the need for external accessories are regarded as a pinnacle goal in the design and construction of modern ones. Staphylococcus aureus (S. aureus), a prominent human pathogen, is responsible for causing a wide variety of infections and chronic diseases. Herein, we present the first instance of a fully integrated wireless microfluidic immunosensing system (FIWMIS) capable of conducting point-of-care S. aureus monitoring in real samples of S. aureus-spiked commercial purified drinking water and S. aureus-spiked watermelon juice. The development of the proposed FIWMIS became a reality by conquering significant engineering hurdles in seamlessly integrating a microfluidic unit for liquid sample transport without the need of an external pump, an immunosensing unit for S. aureus monitoring, and an electronic control unit for signal conversion and wireless transmission. Such full integration culminated in a FIWMIS that upholds its pump-free, wireless, and low-cost characteristics for portable monitoring of S. aureus.

Real-time monitoring of aero-engine vibration signals by wireless communication technology

Abstract The conventional way to monitor the vibration signals of aircraft engines is to use wired communication sensors to transmit and collect the signals on a fixed platform on the ground. The signal acquisition equipment of wired communication technology has various drawbacks, resulting in the inability to collect vibration signals when the object under test is in real operating conditions. Based on previous studies, this research team uses a 2.4G wireless transmission scheme to realize short-distance wireless transmission of aero-engine vibration signals, and a 4G cellular communication scheme to realize long-distance wireless transmission of aero-engine vibration signals. The acquired signals are displayed and monitored using the tool developed in LabVIEW2022. The designed tool is successfully applied in the engineering practice of engine maintenance, realizing the remote real-time monitoring of the engine operation status, shortening the monitoring cycle of the equipment from hourly to real-time level, and greatly facilitating the technical support work of engineers and technicians.

Adaptive Transmission of Cognitive Radio- and Segmented zeRIS-Aided Symbiotic Radio

Adaptive Transmission of Cognitive Radio- and Segmented zeRIS-Aided Symbiotic Radio

Automated Attendance System with GPS-Integrated with Enhanced Navigation Tracking

With the rise of automation and smart technologies in educational institutions, efficient and reliable attendancetracking methods have become increasingly essential. Traditional attendance systems, which often involve manual or barcode scanning methods, are time-consuming and prone to inaccuracies. This research paper presents an innovative approach to student attendance tracking, utilising GPS-integrated barcode identification with wireless data transmission. The proposed system is designed to improve attendance accuracy and streamline student identification without the need for students to physically interact with scanning devices. By integrating GPS and barcode systems into the door panel, this attendance solution detects student presence in classrooms, records attendance, and transmits data in real time.

Wireless Data Transmission through Concrete Structures

Chloride ion presence in the concrete pore solution is an important factor in the initiation of rebar corrosion. Therefore, elevated chloride concentration in the pore solution needs to be detected as early as possible. For this early detection to be achieved, it is ideal to deploy sensors inside the concrete structure itself. This allows real time sampling of the pore solution which is closest to the rebar. To achieve this one needs to have a system based on wireless communication which allow the sensors to communicate within the structure. This would avoid wired communications methods, which impart fragility and implementation difficulties. This literature review paper endeavours to look at the various types of radiation which can be harnessed to penetrate through the opaque concrete structure. Potential data transmission methods utilising Radio Frequency Radiation, Ultrasonic Radiation, X-Ray Radiation and Neutron Beam Radiation physics were reviewed and evaluated against a set of parameters. The paper scores each radiation type against System Size, Power Supply Requirements, Transmission Range, Complexity of Circuits and Safety issues. Through these scores, each transmission technology was graded on its potential to act as the basis on which to build a micrometre sized intra-concrete data transmission system. The paper shows that ultrasonic radiation is the most promising radiation technology for use in this application.