Solution-processable 2D materials (2DMs) are gaining attention for applications in logic, memory, and sensing devices. This review surveys recent advancements in memristors, transistors, and sensors using 2DMs, focusing on their charge transport mechanisms and integration into silicon CMOS platforms. We highlight key challenges posed by the material’s nanosheet morphology and defect dynamics and discuss future potential for monolithic 3D integration with CMOS technology.
A low-cost L-band patch antenna featuring frequency-dependent radiation patterns is presented. The antenna operates within the 1.20-1.38 GHz frequency range. Through optimization of a parasitic pixel layer, the radiating beams can be precisely controlled to exhibit distinct characteristics within the frequency band. Specifically, the designed antenna has a -30° directive beam, a wide-beam, and a +30° directive beam at 1.24, 1.28, and 1.34 GHz, respectively. This versatility enables selection of different radiation beams to achieve desired coverage ranges. The antenna with diverse radiation patterns holds significant promise for applications in wireless communication devices, observation systems, and satellite technology.
An optically transparent and lightweight stacked filtering patch antenna for conformal and flexible applications is presented. The antenna consists of two layers of patches utilizing optically transparent fluorinated ethylene propylene (FEP) film and polyethylene foam that are stacked for bandwidth enhancement while maintaining a high level of conformability. The antenna is designed for L-band applications and tested for the flat case as well as conformed to a cylinder with a radius of 200 mm, 160 mm, 80 mm, and 40 mm. The antenna has a bandwidth of 16.1% (1.152–1.355 GHz) and the gain varies from 7.4 dBi to 3.6 dBi for different cases of conforming to a cylinder.
Multilayer flexible and conformal antennas are demonstrated using semi-elliptical-shaped corrugated mesh patterns using copper-clad polyimide film. The antenna consists of corrugated strips with varying corrugation sizes that are joined together to form an uneven-spaced mesh pattern. Two layers of mesh patterns are stacked to provide increased bandwidth. The antenna can easily be conformed to surfaces along the horizontal, vertical, and diagonal directions. An L-band antenna is optimized and tested for the flat case as well as conformed to cylinders with a radius of 200 mm, 160 mm, 80 mm, 40 mm, and 20 mm.
In the field of neuroscience, understanding the complex interactions within the intricate neuron-motor system depends crucially on the use of high-density, physiological multiple electrode arrays (MEAs). In the neuron-motor system, the transmission of biological signals primarily occurs through electrical and chemical signaling. Taking neurons for instance, when a neuron receives external stimuli, it generates an electrical signal known as the action potential. This action potential propagates along the neuron’s axon and is transmitted to other neurons via synapses. At the synapse, chemical signals (neurotransmitters) are released, allowing the electrical signal to traverse the synaptic gap and influence the next neuron. MEAs can provide unparalleled insights into neural signal patterns when interfacing with the nerve systems through their excellent spatiotemporal resolution. However, the inherent differences in mechanical and chemical properties between these artificial devices and biological tissues can lead to serious complications after chronic implantation, such as body rejection, infection, tissue damage, or device malfunction. A promising strategy to enhance MEAs’ biocompatibility involves minimizing their thickness, which aligns their bending stiffness with that of surrounding tissues, thereby minimizing damage over time. However, this solution has its limits; the resulting ultrathin devices, typically based on plastic films, lack the necessary stretchability, restricting their use to organs that neither stretch nor grow.
Researcher/Author:
Zhi Jiang, Ming Zhu, and Xiaodong Chen
Published in:
Accounts of Chemical Research (ACS Publications), 18 July 2024
In realizing scent digitalization for real-world scenarios, robust and high-performance scent-sensing techniques lay the foundation, which is much more challenging than existing image or sound digitalization techniques. Current scent sensing predominantly utilizes single sensing techniques that only detect a dominant aspect of scent properties, thus limiting their ability to capture the full complexity of scents. In contrast, integrated multimodal scent sensing offers promising avenues for scent digitalization, enabling comprehensive and complementary profiling through multi-perspective analysis of scents. In this perspective, traditional scent-sensing techniques are reassessed in their sensing mechanisms and advantageous sensing capabilities. We hope that the perspective presented will inspire more scent-sensing systems and expand the application scenarios of scent digitalization.
Researcher/Author:
Jianwu, Yifei Luo, Xian Jun Loh and Xiaodong Chen
Published in:
July 2024, Matter, 3 July 2024
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DOI: http://dx.doi.org/10.1016/j.matt.2024.05.040
E-Textile Battery-Less Walking Step Counting System with <23 pW Power, Dual- Function Harvesting from Breathing, and No High-Voltage CMOS Process June 16, 2024
Publication
E-Textile Battery-Less Walking Step Counting System with <23 pW Power, Dual- Function Harvesting from Breathing, and No High-Voltage CMOS Process
An e-textile walking step counting full system (smart T-shirt) is presented. Harvesting from co-designed low-voltage triboelectric nanogenerator (TENG) pushes over-voltage protection/rectification on chip. Conformability and minimal off-chip components are achieved via dual-function harvester/sensor reuse and battery/passive elimination. Always-on power reduction to pWs enables uninterrupted operation while solely powered by breathing harvesting.
Researcher/Author:
Anil Kumar Gundu, Luigi Fassio and Massimo Alioto
Published in: 2024 IEEE Symposium on VLSI Technology and Circuits (VLSI Technology and Circuits),2024/06/16
A 4×1 L-band conformal receiving array with full digital beamforming for four simultaneous polarizations and sidelobe suppression is presented. The array is based on a reconfigurable quad-polarization antenna featuring four primary patches with secondary patches to enhance the bandwidth. The resultant 16 channels are combined into eight channels through hybrid couplers which introduce the required fixed phasing. The eight channels are digitized and processed in an AMD radio frequency system-on-chip (RFSoC). The polarizer for the four polarizations (HP, VP, LHCP, and RHCP) and the beamformer are implemented in the RFSoC as well as suppression of sidelobe levels (SLL). The beamforming performance of the conformal array is demonstrated for several beamsteering cases.
Researcher/Author:
Peizhuo Yang, Gong Chen, Koen Mouthaan
Published in:2024 IEEE Radar Conference (RadarConf24)
Rapid-Response Water-Shrink Films with High Output Work Density Based on Polyethylene Oxide and 𝜶-Cyclodextrin for Autonomous Wound Closure June 5, 2024
Publication
Rapid-Response Water-Shrink Films with High Output Work Density Based on Polyethylene Oxide and 𝜶-Cyclodextrin for Autonomous Wound Closure
Conventional wound closure methods, including sutures and tissue adhesives, present significant challenges for self-care treatment, particularly in the context of bleeding wounds. Existing stimuli-responsive contractile materials designed for autonomous wound closure frequently lack sufficient output work density to generate the force needed to bring the wound edges into proximity or necessitate stimuli that are not compatible with the human body. Here, semi-transparent, flexible, and water-responsive shrinkable films, composed of poly(ethylene oxide) and α-cyclodextrin, are reported. These films exhibit remarkable stability under ambient conditions and demonstrate significant contraction (≈50%) within 6 s upon exposure to water, generating substantial contractile stress (up to 6 MPa) and output work density (≈1028 kJ m−3), which is 100 times larger than that of conventional hydrogel and 25 times larger than that of skeletal muscles. Remarkably, upon hydration, these films are capable of lifting objects 10 000 times their own weight. Leveraging this technology, water-shrink tapes, which, upon contact with water, effectively constrict human skin and autonomously close bleeding wounds in animal models within 10 seconds, are developed further. This work offers a novel approach to skin wound management, showing significant potential for emergency and self-care scenarios.
A foldable dual linear polarized antenna with gamma match at L band is presented. Two crossed dipoles are fed by two feed networks with gamma match to achieve the two polarizations. Since the gamma match uses the ground in the center of the radiator, it is relatively easy to extend the conventional single polarization to dual polarization. The feed networks are printed on two sides of a rigid PTFE substrate, while the radiators are printed on one side of flexible copper cladded polyimide substrate. Taking advantage of feed network’s planar configuration and the use of flexible substrate, the dualpolarized antenna can be folded with low profile. Thus the proposed dual polarized dipole antenna is a good candidate for L-band space applications where the antenna must be stowable and deployable.
Researcher/Author:
Gong Chen, Fujiang Lin, and Koen Mouthaan
Published in: 2024 IEEE International Workshop on Antenna Technology (iWAT)
A method is presented to estimate the shape of a deformed uniform linear array (ULA) using two received signals. The two signals can be noiseless ir contaminated with noise, which is of practical importance when deformation must be estimated using signals from a distance away from the array. Two sources with known angle of arrival (AOA) are used to estimate the distance and the angle of the deformed element with respect to the non-deformed element. The proposed estimation technique is applied to a deformed array with eight elements, and parametric studies of estimation performance are provided.
Researcher/Author:
Jiahao Wang and Koen Mouthaan
Published in: 2024 IEEE International Workshop on Antenna Technology (iWAT)
A low-profile, lightweight, and optically semi-transparent multilayer antenna based on stacked patches for conformal applications is presented. The antenna employs multiple layers of patches utilizing the polytetrafluoroethylene film and polyethylene foam for bandwidth enhancement and high level of bending. The antenna is designed for the L-band and tested for the flat case as well as conformed to a cylinder with radius of 200 mm, 160 mm, 80 mm, and 40 mm. The proposed antenna has a bandwidth of 1.172–1.328 GHz (12.5%), and the gain varies from 8.14 dBi to 5.08 dBi for different cases of conforming to a cylinder.
Researcher/Author:
Mohammad Ameen and Koen Mouthaan
Published in: 2024 IEEE International Workshop on Antenna Technology (iWAT)
Lightweight flexible antennas based on singlelayer and multilayer corrugated copper clad polyimide films are presented. The single-layer corrugated patch antenna (SLCPA) comprises a patch radiator with semicircular-shaped corrugations. In the multilayer corrugated patch antenna (MLCPA) an additional corrugated patch is added to the SLCPA to increase the bandwidth while maintaining good conforming properties. Both antennas are designed for the L band and tested for the flat case as well as conformed to a cylinder with radius of 160 mm, 80 mm, 40 mm, and 20 mm. The MLCPA has a bandwidth of 1.198–1.33 GHz (10.42%), and the gain varies from 5.78 dBi to 8.67 dBi for different cases of conforming to a cylinder.
Researcher/Author:
Mohammad Ameen and Koen Mouthaan
Published in: 2024 IEEE International Workshop on Antenna Technology (iWAT)
Radio frequency system-on-chip (RFSoC) has become a promising candidate for replacing traditional analog and digital front-ends in the development of fully digital phased arrays. As the sampling frequency is limited to a few GHz, RFSoC can’t be used for direct sampling at X-band. In this contribution, an X-band phased array receiver system with RFSoC is presented, which includes down-conversion to Lband, in which all the channel imperfections are incorporated in the beamforming algorithm. A rigid-flexible 44 antenna array, consisting of four subarays, is designed and fabricated for demonstration and verification. The proposed method is demonstrated using minimum variance distortionless response (MVDR) beamforming applied in the Xilinx RFSoC ZCU111.
Researcher/Author:
Gong Chen, Peizhuo Yang, Fujiang Liny, and Koen Mouthaan
Published in: 2024 18th European Conference on Antennas and Propagation (EuCAP)
A 4×1 L-band receiving phased array with full digital beamforming for four simultaneous polarizations is presented. The array is based on a reconfigurable quad-polarization antenna consisting of four patches with secondary patches to increase the bandwidth. The resulting 16 channels are combined into eight channels using hybrid couplers that provide a layer of fixed phasing. The eight channels are digitized using a Xilinx radio frequency system-on-chip (RFSoC) and the polarizer for the four polarizations (V, H, LHCP, and RHCP) and the beamformer are implemented in the RFSoC. The beamforming performance for the four simultaneous polarizations is demonstrated.
Researcher/Author:
Peizhuo Yang, Gong Chen, Jiahao Wang and Koen Mouthaan
Published in: 2024 18th European Conference on Antennas and Propagation (EuCAP)
Phased arrays often use a uniform rectangular array (URA) with phasing of the elements. In large phased arrays, deformations may occur due to fabrication tolerances and other influences, which will cause errors in the position of the antenna elements. The impact of such errors on the antenna pattern can be analyzed by sampling the distribution of the deformations and computing the mean radiation pattern (MRP). However, this will be time-consuming when the number of elements is large and it will not give much insight into the impact of the deformations. Here, an analytical expression is presented for the MRP of a deformed URA considering different distributions of the deformation in x, y, and z, including uniform distribution, normal distribution, and triangular distribution. As an example, the analytical expression is compared to Monte Carlo simulations for a 4×4 array and good agreement is observed. The analytical expression is further used to investigate the impact of the deformation on the pattern and the gain of a 4×4 and a 16×16 array with isotropic elements under different distributions.
Researcher/Author:
Jiahao Wang and Koen Mouthaan
Published in: 2024 18th European Conference on Antennas and Propagation (EuCAP)
