IEEE Journal on Flexible Electronics最新文献

{"title":"On-Body Force Sensing Using a Soft E-Textile Matrix: Development, Modeling, and Evaluation","authors":"Alireza Golgouneh;Lucy E. Dunne","doi":"10.1109/JFLEX.2025.3585873","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3585873","url":null,"abstract":"Accurate force estimation on the human body is inherently challenging due to variations in body geometry, surface curvature, and soft tissue deformation, which introduce complexities in sensor response. In this article, we present the development and evaluation of a low-profile, textile-based, and biocompatible flexible sensor matrix composed of 72 sensing cells (<inline-formula> <tex-math>$6times 12$ </tex-math></inline-formula> configurations) with a spatial fine resolution of 1 cm², designed for wearable applications requiring precise on-body force measurement. The goal of this article is to improve force-estimation accuracy for applications such as medical monitoring, rehabilitation, and human-computer interaction. This study contributes a fully soft e-textile matrix together with a matching data-driven modeling framework. We investigated multiple modeling techniques, including exponential and polynomial regression, as well as neural-network architectures such as sequential multilayer perceptron (MLP) and long short-term memory (LSTM) networks. The LSTM model outperformed others by capturing hysteresis effects and improving force-estimation accuracy. The sensor matrix was first validated using balance weights on flat surfaces, achieving a root mean square error (RMSE) of 0.02 N. It was, then, evaluated on soft, curved mannequin surfaces representing varying geometries—low (torso), medium (thigh), and high (forearm) curvatures—resulting in a minimum RMSE of 0.056 N, a maximum error of 0.14 N, and an average RMSE of 0.09 N. These results demonstrate the matrix’s accuracy and robustness for on-body force sensing on deformable, nonuniform surfaces.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 9","pages":"373-384"},"PeriodicalIF":0.0,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphysics Testing and Numerical Modeling of Fully 3-D/Inkjet-Printed Microstrip Line Under 12500 Cycles of Bending for 5G/mm-Wave Flexible Hybrid Electronics Packaging","authors":"Yi Zhou;Kexin Hu;Manos M. Tentzeris;Suresh K. Sitaraman","doi":"10.1109/JFLEX.2025.3585058","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3585058","url":null,"abstract":"Additive manufacturing is increasingly used in the fabrication of flexible electronics. A critical component of flexible electronics packages for 5G/mm-wave applications, the interconnect needs to demonstrate low loss and adequate mechanical reliability while surviving a large number of bending cycles to fulfill its intended functionality under flexible conditions. In this study, a proof-of-concept inkjet-printed microstrip line on a 3-D-printed polypropylene (PP) substrate is designed and fabricated, with metallization thicknesses of three, six, and nine layers. Initial tests reveal excellent insertion loss values at flat conditions, with thick samples showing lower insertion losses. In monotonic mandrel bending tests, the insertion loss is observed to increase with the strain but remain below 0.130 dB/mm even for the smallest bending radius of 1 in. Electrical numerical models developed in CST Studio Suite are used to analyze the impact of various factors on the observed insertion loss, with results showing minimal contribution from the shape change and more significant contribution from changes in conductivity and surface roughness, which effectively explains discrepancies between simulations and empirical observations. Mechanical-loading-induced geometry modifications and property changes in the printed silver nanoparticle (AgNP) layer are also quantified using mechanical finite-element analysis (FEA) simulations, scanning electron microscopy (SEM), profilometer surface scan, and four-point probe resistance measurements, which provide further mechanistic insights that help improve electrical models to capture empirical observations. Cyclic mandrel bending tests up to 12500 cycles are conducted and results show that six-layer samples offer the best balance between electrical performance and mechanical reliability for 5G and mm-wave applications. Numerical models in CST Studio Suite suggest that while local cracks and microstructure changes due to cyclic bending could not be fully represented by the decrease in conductivity alone, the increase in macroscopic surface roughness serves as a representative equivalent. This study contributes to the understanding of additively fabricated flexible electronics components by providing important empirical data under bending conditions and valuable mechanistic insights that help improve predictive models.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 7","pages":"278-292"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid System in Foil Containing Secure Identification and Temperature Sensing Units","authors":"Alexander Scholz;Shawon Alam;Wacime Hadrich;André Schröder;Tim Wolfer;Martin Friedrich;Thomas Kister;Makara Lay;Sophie Sauva;Ulrike Passlack;Manuel Campana;Liane Koker;Axel Sikora;Tobias Kraus;Jasmin Aghassi-Hagmann","doi":"10.1109/JFLEX.2025.3581864","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3581864","url":null,"abstract":"Flexible hybrid electronics allow for seamless integration of sensing functionalities within materials, nonconformal surfaces, and products, and thus can enable novel value chains. Next to new functionalities, product authenticity plays a crucial role in complex global supply chains. This holds especially true, when products are deployed in critical environments, such as the industrial or automotive sector, where product failure can be fatal. In this work, we present a secure hybrid system, which contains a custom-designed, thinned application-specific integrated circuit (ASIC) in foil, as well as two printed temperature sensing elements that are seamlessly embedded in an industrial process fabricated automotive coolant hose and an inkjet-printed unique identifier in the form of a physically unclonable function (PUF) to derive the system’s authenticity. We show the results of the standalone hose-integrated temperature sensors, the bulk ASIC verification results prior to thinning and foil integration, and the fully assembled integrated hybrid system. The thinned ASIC in foil communication interfaces, its circuit building blocks, and the integrated printed components were successfully commissioned. We show the obtained temperature response and the unique identification by generating the challenge-response pairs (CRPs) of the PUF over 1000 repetitions. The security circuit shows only 0.0084% of flipped bits at <inline-formula> <tex-math>$T = {25}~^{circ } $ </tex-math></inline-formula>C, which makes it well-suited to be used as PUF.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 6","pages":"242-250"},"PeriodicalIF":0.0,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11045752","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IEEE Journal on Flexible Electronics Publication Information","authors":"","doi":"10.1109/JFLEX.2025.3573865","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3573865","url":null,"abstract":"","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 4","pages":"C2-C2"},"PeriodicalIF":0.0,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11045265","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interconnecting Mechanically Different Components Using Magnetically Aligned Anisotropic Conductive Epoxy for Flexible and Stretchable Electronics Integration","authors":"Riadh Al-Haidari;Udara Somarathna;Behnam Garakani;Detlef-M. Smilgies;Mohammed Alhendi;Zhi Dou;El Mehdi Abarra;Mark Schadt;Mark Poliks;Andrew Stemmermann;Daniel Balder;Ekaterina Dvoretskaya;Christopher Tabor;Nancy Stoffel","doi":"10.1109/JFLEX.2025.3580695","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3580695","url":null,"abstract":"The use of magnetically aligned anisotropic conductive epoxy (MA-ACE) as a versatile interconnection technology for flexible and stretchable electronics is explored. The MA-ACE leverages magnetically induced self-assembly of vertically conductive columns within a polymer matrix. Additionally, it offers low curing temperatures and pressure-less assembly while providing strong adhesion to a wide range of materials. Moreover, it integrates well with traditional surface mount technology (SMT) lines. The MA-ACE was used to interconnect microelectronic components with different mechanical properties: 1) printed polymerized liquid metal networks (Poly-LMNs) to surface mount device (SMD), electronic textiles (E-textiles), and copper-clad laminates; 2) E-textiles to SMDs; 3) E-textiles to other E-textiles; and 4) screen-printed flexible silver to SMDs at variable pitch sizes on either polyethylene terephthalate (PET) or polyimide (PI) substrates. The performance of the MA-ACE interconnects was assessed under mechanical stress conditions, including tensile tests, shear tests, fatigue cycling, and exposure to various temperature and humidity conditions. The MA-ACE was found to be highly compliant, successfully bonding different materials while maintaining electrical continuity and mechanical reliability. The results showed that the MA-ACE exhibited a high yield of 86%–100%, strong adhesion to all surfaces, low contact resistance (~50–150 m<inline-formula> <tex-math>$Omega $ </tex-math></inline-formula> per connection), and high x–y isolation (<inline-formula> <tex-math>$gt 10^{11}~Omega $ </tex-math></inline-formula>). While the MA-ACE was mechanically robust under stress across all interconnection configurations, other components, including E-textiles, Poly-LMNs, and printed flexible silver traces, demonstrated failures such as leakage and delamination.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 7","pages":"262-277"},"PeriodicalIF":0.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Assessment of Flexible Uniplanar SSPP-Based Endfire MIMO Antenna for B5G Radio Stripe Network Applications","authors":"Abhishek Maganbhai Sonagara;Mohit Mishra;Rakhesh Singh Kshetrimayum;Emil Björnson;Zhi Ning Chen","doi":"10.1109/JFLEX.2025.3578588","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3578588","url":null,"abstract":"An effective way to implement a cell-free massive multiple-input multiple-output (CF-mMIMO) network is the radio stripe network (RSN) concept, in which all access points (APs), which have antennas and other signal processing units needed to serve user equipments (UEs), share a common stripe that can be easily deployed over existing infrastructures. This article proposes an MIMO antenna for the first time that satisfies all the requirements for the RSN applications, such as a flexible and an ultrathin profile, a very low volume, and an endfire beam with a downward tilt to cover all UEs present below the deployed radio stripes. A spoof surface plasmon polariton (SSPP)-based structure is used over a flexible substrate to achieve a flexible and ultrathin MIMO antenna. The SSPP transmission line (TL) uses U-shaped unit cells. An equivalent circuit (E.C.) model is proposed for the U-shaped SSPP unit cell to analyze the effect of the design parameters of the unit cell on the dispersion curve. A single metal-layered and simple hook-shaped design of an open-ended SSPP TL is used to achieve a 45° downward-tilted endfire radiation beam. E.C. models are proposed to understand the design evolutions of the antenna. A filtering mechanism is employed over the coplanar waveguide (CPW) to the SSPP transition section to filter out unwanted higher frequencies. An SSPP-based director is shared between two orthogonally placed hook-shaped antenna elements to enhance the directivity. The fabricated antenna is placed on flat and curved surfaces made up of wood and brick wall for measurements and validation. The MIMO antenna has a maximum gain of 7.4 dBi with an impedance bandwidth of 42.2%, isolation up to 26.7 dB, and envelope correlation coefficient (ECC) below 0.19. Besides its ultrathin flexible profile and extremely low volume, the proposed MIMO antenna has a tilted beam and wideband operation, making it an excellent choice for beyond fifth-generation (5G) RSN applications.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 7","pages":"252-261"},"PeriodicalIF":0.0,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144909388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrospun Hollow Nanofiber Surfaces as Dielectric Mediums for Highly Sensitive Flexible Capacitive Pressure Sensors in Low-Pressure Regimes","authors":"Shaharyar Siddique;Amit Barua;Rituporn Gogoi;Vipul Sharma","doi":"10.1109/JFLEX.2025.3577111","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3577111","url":null,"abstract":"Flexible capacitive pressure sensors have gained significant attention in flexible electronics, offering extensive material and design options for various active sensing needs. Despite significant advances, achieving high sensitivity at very low pressures (<5>−1</sup> at a pressure of 1 kPa. This performance gain is attributed to the hollow air core of the fibers, which improves dielectric properties by increasing surface area, roughness, deformability, and charge formation. However, the sensor’s sensitivity reduces at higher pressures, ultimately falling below that of conventional single-shell fiber-based sensors due to the reduced influence of the air gaps within the hollow fibers. These findings highlight the potential of hollow fiber architectures for low-pressure-sensing applications while also highlighting opportunities for further optimization.","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 6","pages":"226-233"},"PeriodicalIF":0.0,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11025829","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144740012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IEEE Journal on Flexible Electronics Publication Information","authors":"","doi":"10.1109/JFLEX.2025.3562684","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3562684","url":null,"abstract":"","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 2","pages":"C2-C2"},"PeriodicalIF":0.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10979401","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143883398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guest Editorial: Special Issue of Selected Extended Papers From the IEEE International Conference on Flexible, Printable Sensors and Systems (FLEPS) 2024","authors":"Matti Mantysalo;Gaetano Marrocco;Shweta Agarwale;Gerd Grau;Wei Gao","doi":"10.1109/JFLEX.2025.3556389","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3556389","url":null,"abstract":"","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 1","pages":"2-3"},"PeriodicalIF":0.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10977762","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IEEE Journal on Flexible Electronics Publication Information","authors":"","doi":"10.1109/JFLEX.2025.3560494","DOIUrl":"https://doi.org/10.1109/JFLEX.2025.3560494","url":null,"abstract":"","PeriodicalId":100623,"journal":{"name":"IEEE Journal on Flexible Electronics","volume":"4 1","pages":"C2-C2"},"PeriodicalIF":0.0,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10977761","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143875236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}