Yuanjin Zheng

• Ph.D.
• Professor at Nanyang Technological University

Handwriting identification is widely accepted as scientific evidence. However, its authenticity is questioned because it depends on the appraiser's professional skills and susceptibility to deliberate false identification by expert witnesses. Consequently, there is an urgent need for an effective handwriting identification system (HWIS) that reduce...

Proximity‐touch intention recognition is critical for embodied intelligence, enabling precise environmental perception and effective human–agent interactions. However, the material properties of conventional sensor architectures are not sufficiently sensitive and have poor spatial resolution and inadequate pressure detection capabilities. These nec...

Electronics continue to drive technological innovation and diversified applications. To ensure efficiency and effectiveness across various interactive contexts, the ability to adjust operating functions or parameters according to environmental shifts or user requirements is highly desirable. However, due to the inherent limitations of nonadaptive d...

Intelligent robots, equipped with perception, cognition, and learning capabilities, are transforming the manner by which complex tasks are approached, enhancing autonomy, efficiency, and adaptability. By contrast, conventional robotics typically struggle with precision and reliability in tasks such as grasping and recognition owing to their limited...

The application of flexible mechanical biosensors in biological systems is revolutionizing health monitoring and medical practices, particularly in the field of critical care medicine. The rapid development in this field enables the real-time, efficient detection of various mechanical signals within the human body and offers unique advantages, such...

Embodied intelligent tactile systems represent a groundbreaking paradigm for autonomous agents, facilitating dynamic perception and adaptation in unstructured environments. Traditional von Neumann architectures suffer from inefficiencies due to the separation of sensing and memory units, where mechanical relaxation is often overlooked as non‐inform...

Topological crystals provide a transformative platform for chip-scale signal processing, offering exceptional robustness, precise wave manipulation, and ultra-compact integration. However, their extension to phononics, particularly for controlling surface acoustic wave (SAW), has thus far been limited to lower-order topological states. This restric...

Partial discharge (PD) detection is crucial for maintaining insulation systems of high-voltage equipment. Enhancing diagnostic credibility and expanding additional system functionalities can be achieved by correlating signals detected from multiple measurement techniques. In this article, a noncontacting electromagnetic-acoustic (EMA) measurement t...

Snapshot hyperspectral imaging (SHI) is increasing demand for various applications in dynamic scenes. Current mainstream solutions rely on machine learning with open‐source datasets to acquire fixed compression encoder and reconstruction decoder, which limits their generalizability across diverse real‐world scenarios. Herein, these challenges are a...

Miniaturized and lightweight see‐through near‐eye displays are desirable for wearable computing applications. With the recent rapid advances in ultra‐thin metasurface optics, the compactness and weight of near‐eye displays can be improved without compromising the performance of the real‐virtual scene. In this paper, a proof‐of‐concept solution, usi...

The miniaturization and real time imaging capability have always been the desired properties of photoacoustic imaging (PAI) system, which unlocked vast potential for personalized healthcare and diagnostics. While the imaging quality and resolution in such systems are inferior due to physics and system volume constraints, which limited its wide depl...

Acoustic resolution photoacoustic microscopy (AR-PAM) is a novel medical imaging modality, which can be used for both structural and functional imaging in deep bio-tissue. However, the imaging resolution is degraded and structural details are lost since its dependency on acoustic focusing, which significantly constrains its scope of applications in...

Digitally programmable metasurfaces are of potential use in next-generation mobile communications due to their ability to perform wireless data transmission without digital-to-analogue conversion or frequency mixing. However, communication networks based on programmable metasurfaces currently suffer from relatively low data transmission rates and l...

This work proposes the Poisson equation formulation of the Retinex model for image enhancements using a low-power graph hardware accelerator performing finite difference updates on a lattice graph processing element (PE) array. By encapsulating the underlying algorithm in a graph hardware structure, a highly localized dataflow that takes advantage...

This brief presents a 357-706 MHz dual-mode lowpass filter featuring an oscillator-based calibration method to address bandwidth deviations caused by process variations and component mismatches, eliminating the need for a highfrequency reference signal. Compared to conventional replicabased approaches, the proposed dual-mode oscillator calibration...

This article presents a dual-core, dual-mode digitalcontrolled oscillator (DCO) featuring a novel transformer-based resonator that minimizes parasitics in the switch connection lines and enhances the design flexibility of the resonator. Fabricated using 65-nm CMOS technology, the DCO occupies a die area of 0.76 mm2. Powered by a 1.2-V supply, it co...

Various data-driven computation-in-memory (CIM) architectures have been proposed to reduce inference energy. However, most data-driven CIM architectures require specific conditions to achieve energy savings (e.g., zero skip requires a ReLU activation function). This paper proposes a convolutional window-inspired similarity-aware CIM that saves ener...

A cryogenic low-voltage, broadband low-noise amplifier(LNA) has been designed for qubit state readout systems. The proposed LNA utilizes passive components for noise cancellation. A tri-coupled transformer is utilized to simultaneously achieve broadband input impedance matching and noise matching. Additionally, it incorporates capacitive feedback a...

An innovative hybrid physical model for gallium nitride high-electron-mobility transistors (GaN HEMTs) that leverages an artificial neural network (ANN) approach is proposed. This model utilizes ANN to formulate surface potentials, correlating them with the device’s RF and dc behaviors in accordance with the advanced SPICE model for GaN HEMTs (ASM-...

Expanding the metal–semiconductor–metal (MSM) structure to encompass a broader range of passive networks is crucial for enhancing the understanding of carrier transport theory and broadening its application scope. Here, a mechanism to modulate the Schottky barrier using mechanical friction is proposed to generate electricity. The findings reveal th...

In this article, a novel compact near-equidistant multimode resonator that integrates skyrmionic metamaterial (SM) with a substrate integrated waveguide (SIW) cavity is proposed. This planar SM-SIW cavity resonator can generate various microwave skyrmion modes, effectively demonstrating the feasibility of the cavity excitation and integration desig...

Fast and accurate recognition of partial discharge (PD) patterns is essential to prevent insulation failure-related outages of industrial equipment. The ultrahigh-frequency (UHF) methods have been widely used for PD diagnosis due to their good versatility and noncontact capabilities. However, in harsh environments with significant noise and electro...

Robotic skins that integrate artificial tactile sensing elements can substantially complement the perception dimension of social robots, presenting an indispensable part in human‐robot interaction (HRI). However, existing design frameworks compromise between versatility and sustainability due to the restricted range of characteristics available for...

The contact-free sensing nature of Wi-Fi has been leveraged to achieve privacy breaches such as keystroke inference (KI). However, the use of channel state information (CSI) in existing attacks is highly questionable due to its signal instability and hardness to acquire. Moreover, such Wi-Fi-based attacks are confined to only one victim because...

Developing intelligent methods for partial discharge (PD) diagnosis, capable of handling various types of insulation defects in switchgear, has garnered significant attention in recent years. Certain PD signals exhibit similar characteristics, often leading to their confusion with noisy signals during data acquisition. To mitigate noise interferenc...

Optical encryption is pivotal in information security, offering parallel processing, speed, and robust security. The simplicity and compatibility of speckle‐based cryptosystems have garnered considerable attention. Yet, the predictable statistical distribution of speckle optical fields’ characteristics can invite statistical attacks, undermining th...

In this paper, a novel planar microwave multimode cavity resonator incorporating plasmonic metamaterial structure (PMS) and half-mode substrate integrated waveguide (HMSIW) cavity is proposed for microfluidic glucose monitoring. The composite PMS-HMSIW cavity resonator (CPHCR) is designed by integrating subwavelength slotted PMS into an annular HMS...

Continuous, long-term monitoring of hazardous, noxious, explosive, and flammable gases in industrial environments using electronic nose (E-nose) systems faces the significant challenge of reduced gas identification accuracy due to time-varying drift in gas sensors. To address this issue, we propose a novel unsupervised attention-based multi-source...

High‐precise, crosstalk‐free tactile perception offers an intuitive way for informative human‐machine interactions. However, the differentiation and labeling of touch position and strength require substantial computational space due to the cumbersome post‐processing of parallel data. Herein, a programmable and robust electronic skin (PR e‐skin) wit...

Tactile intent recognition systems, which are highly desired to satisfy human's needs and humanized services, shall be accurately understanding and identifying human's intent. They generally utilize time‐driven sensor arrays to achieve high spatiotemporal resolution, however, which encounter inevitable challenges of low scalability, huge data volum...

A 4–6GHz cryogenic radio frequency digital-to-analog converter (RF-DAC) is presented for quantum computing application in this brief. The RF-DAC is implemented with a switched-capacitance topology for its characteristic of being insensitive to cryogenic temperature. A cross-connection switched capacitor array is also integrated into the RF-DAC to e...

Touch control intention recognition is an important direction for the future development of human–machine interactions (HMIs). However, the implementation of parallel‐sensing functional modules generally requires a combination of different logical blocks and control circuits, which results in regional redundancy, redundant data, and low efficiency....

A wearable dual-band and dual-circularly polarized (DBDCP) antenna using a dodecagonal truncate pyramid-shaped artificial magnetic conductor (AMC) reflector for gain enhancement is proposed in this paper. Firstly, a compact deformed quadruple inverted-F antenna (QIFA) with meander-line-shaped radiation patches has been developed as the radiator. Th...

As time goes by, the rails of high-speed trains are subject to long-term extrusion and natural factors, and defects will gradually appear. Therefore, early detection of these defects is extremely important for the maintenance or replacement of rails. In this paper, a set of rail internal crack detection system is proposed and developed, which can b...

Developing an accurate partial discharge (PD) monitoring system for switchgear has attracted significant attention in recent times. Detecting and distinguishing PDs with a portable PD detector is challenging due to the inherent noise interference and the similarity among different PD signals in field conditions. In this study, we propose an innovat...

Partial discharge (PD) detection is critical for diagnosing and maintaining insulation systems of high-voltage equipment. In this paper, a novel broadband three-directional (3-D) omnidirectional magnetic induction-based sensor module is proposed for non-contacting PD detection of high-voltage equipment in the Industrial Internet of Things (IIoT) ap...

This work presents an algorithm hardware co-design implementing a digital neuronal population dynamics simulator intended for the trajectory error correction task within a simultaneous localization and mapping workflow. A custom discretized procedural algorithm approximating a neuronal population dynamics-based inference operation is developed for...

This article presents a novel energy super-regenerative (ESR) wake-up receiver (WuRX) which remarkably reduces the power consumption of baseband circuits through directly detecting the RF signal’s energy and accumulating it at an exponential rate. To improve the sensitivity, a noise power cancellation technique implemented through a pseudo-differen...

Partial discharge is a prevalent sign of insulation aging and defects in high-voltage power equipment. Extended partial discharge can lead to ongoing physical and chemical reactions, resulting in accelerated insulation damage and eventual equipment failure. To early detect partial discharge, this paper proposes a novel wideband high-frequency coil...

This article presents a cryogenic transmon qubit state controller integrated circuit (IC) working at a temperature of 3.5 K for superconducting quantum computing (QC) applications. The qubit state controller IC comprises a polar-modulation-based XY -path driver and a current-steering digital-to-analog converter (DAC)-based Z -path driver. To ge...

To achieve accurate detection and recognition of partial discharge (PD) in switchgear, developing an intelligent PD diagnosis system has garnered significant attention in recent years. Due to inevitable noise interference and high similarity of different PD signals, detecting and identifying PDs using a portable PD detector poses significant challe...

Among many $k$ -winners-take-all ( $k$ WTA) models, the dual-neural network (DNN- $k$ WTA) model is with significantly less number of connections. However, for analog realization, noise is inevitable and affects the operational correctness of the $k$ WTA process. Most existing results focus on the effect of additive noise. This brief studies...

Accurate calculation of joint acceleration online is critical for detecting robot collisions when used in inverse dynamics to calculate joint torques. The conventional method for calculating joint acceleration is to employ the twice differentiation based on encoder data, which suffers from the problem of causing joint acceleration with excessive no...

This article proposes a novel reconfigurable multimode microwave sensor integrating with resonance-and transmission-sensing capabilities for real-time noninvasive glucose monitoring. The sensor is initiated by utilizing a dynamic controllable spoof surface plasmon polariton (SSPP) transmission line (TL) and a multimode array resonator based on spoo...

Efficient and flexible interactions require precisely converting human intentions into computer-recognizable signals, which is critical to the breakthrough development of metaverse. Interactive electronics face common dilemmas, which realize high-precision and stable touch detection but are rigid, bulky, and thick or achieve high flexibility to wea...

Quantitative and multiparametric blood analysis is of great clinical importance in cardiovascular disease diagnosis. Although there are various methods to extract blood information, they often require invasive procedures, lack continuity, involve bulky instruments, or have complicated testing procedures. Flexible sensors can realize on-skin assessm...

Intuitive, efficient, and unconstrained interactions require human–machine interfaces (HMIs) to accurately recognize users' manipulation intents. Susceptibility to interference and conditional usage mode of HMIs will lead to poor experiences that limit their great interaction potential. Herein, a programmable and ultrasensitive haptic interface ena...

In the past few decades, feedforward neural networks have gained much attraction in their hardware implementations. However, when we realize a neural network in analog circuits, the circuit-based model is sensitive to hardware nonidealities. The nonidealities, such as random offset voltage drifts and thermal noise, may lead to variation in hidden n...

Rail foot corrosion is an important issue for electrified railway system. It usually initiates at the bottom of rail foot edges covered by a rail clip and is hardly accessible to conventional online inspection systems. To address this problem, this study combines air-coupled ultrasonic transducer (AUT) and laser-induced ultrasonic guided wave to de...

Acoustic resolution photoacoustic microscopy (AR-PAM) is a promising medical imaging modality that can be employed for deep bio-tissue imaging. However, its relatively low imaging resolution has greatly hindered its wide applications. Previous model-based or learning-based PAM enhancement algorithms either require design of complex handcrafted prio...

A novel resonant tri-coil transducer is proposed to induce thermoacoustic (TA) signals for detecting rail internal defects. It consists of a ferrite plate-backed tri-coil and its associated circuits, a shielding layer, and a three-dimensional printed enclosure for supporting and securing. General TA detection theory is illustrated to understand how...

Unlike conventional topological materials that carry topological states at their boundaries, higher-order topological materials are able to support topological states at boundaries of boundaries, such as corners and hinges. While band topology has been recently extended into thermal diffusion for thermal metamaterials, its realization is limited to...

Most of current commercial near‐eye 3D displays use traditional stereoscopic approach to generate the 3D information. A well‐known issue for this type of technology is the vergence and accommodation conflict, which leads to visual confusion and fatigue for the viewer. To address this problem, a proof‐of‐concept solution based on retinal projection...

A novel compact multiple-input multiple-output (MIMO) antenna is proposed with wideband gain enhancement. It consists of two identical antenna elements spacing about half wavelength. First, a 1-to-2 Y-shaped power divider with wideband anti-phase outputs is designed to feed two modified Vivaldi radiators. The currents on the two radiating surfaces...

Among various multi-wave imaging methods, the photoacoustic imaging (PAI) has attracted more attention because it can achieve higher resolution and contrast through combining advantages of light excitation and ultrasound detection. However, due to low restricted laser fluence, large scattering and attenuation in tissue, and low energy conversion ef...

Partial discharge (PD) of overhead lines is an indication of imminent dielectric breakdown and a cause of insulation degradation. Efficient PD detection is the significant foundation of electrical system maintenance. This paper proposes a transformer-based multilevel filtering (TBMF) framework for PD detection. It creates the multilevel filtering m...

Ultra-high frequency (UHF) partial discharge (PD) detection is essential for routine maintenance of gas-insulated switchgear (GIS). Realizing low-noise detection with cost-effectiveness and ease of installation is promising but challenging. This paper presents a novel broadband noise-shaping network (BNSN) integrated with a printed monopole antenna...

An innovative artificial magnetic conductor (AMC)-backed quad-band antenna is proposed with gain enhancement, high out-of-band (OoB) rejection, forward radiation improvement, and backward radiation reduction for intelligent Internet of Vehicle (IIoV)-based sensing and communication. It includes a quad-band microstrip radiator and a tetracyclic nest...

Accurately and quickly identifying the gas composition and estimating the concentration are critical for ensuring industrial gas safety. However, conventional gas discrimination and concentration estimation models are unable to directly employ the raw dynamic response signal of the sensor array to accurately identify gases and estimate their concen...

This brief presents a brief overview of cryogenic CMOS circuits for large-scale quantum computing, especially the cryogenic RF circuits from the functional blocks to system-level ASICs. To start with, the cryogenic CMOS device characteristics of the process nodes ranging from 180nm to 5nm are examined and compared. The cryogenic RF blocks including...

The brain spatula has been an essential neurosurgical instrument since the early 20th century, when medical advancements enabled surgeons to operate deep intracranially for the first time. Monitoring the brain retraction pressure, especially at an early stage of the intradural procedure, is useful in preventing brain damage or postoperative cerebra...

Conventional electromagnetic (EM) sensing techniques such as radar and LiDAR are widely used for remote sensing, vehicle applications, weather monitoring, and clinical monitoring. Acoustic techniques such as sonar and ultrasound sensors are also used for consumer applications, such as ranging and in vivo medical/healthcare applications. It has be...

Highlights Carbon-based gradient resistance element structure is proposed for the construction of multifunctional touch sensor, which will promote wide detection and recognition range of multiple mechanical stimulations. Multifunctional touch sensor with gradient resistance element and two electrodes is demonstrated to eliminate signals crosstalk a...

The human body detects tactile stimuli through a combination of pressure force and temperature signals via various cutaneous receptors. The development of a multifunctional artificial tactile perception system has potential benefits for future robotic technologies, human-machine interfaces, artificial intelligence, and health monitoring devices. Ho...

Information retrieval from visually random optical speckle patterns is desired in many scenarios yet considered challenging. It requires accurate understanding or mapping of the multiple scattering process, or reliable capability to reverse or compensate for the scattering-induced phase distortions. In whatever situation, effective resolving and di...

In this study, a 0.8-V- $V_{in}$ 200-mA- $I_{o}$ capless low-dropout voltage regulator (LDO) is developed for a wireless respiration monitoring system. The biaxially driven power transistor (BDP) technique is proposed in the LDO, with a current driven stimulation on the bulk and a voltage on the gate terminal. With the BDP technique, an adaptivel...

Faced with COVID-19 and the trend of aging, it is demanding to develop an online health metrics sensing solution for sustainable healthcare. An edge radio platform owning the function of integrated sensing and communications is promising to address the challenge. Radar demonstrates the capability for noncontact healthcare with high sensitivity and...