{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,19]],"date-time":"2026-03-19T20:09:41Z","timestamp":1773950981465,"version":"3.50.1"},"reference-count":28,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,8]],"date-time":"2021-01-08T00:00:00Z","timestamp":1610064000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This work describes the design, implementation, and validation of a wireless sensor network for predictive maintenance and remote monitoring in metal-rich, electromagnetically harsh environments. Energy is provided wirelessly at 2.45 GHz employing a system of three co-located active antennas designed with a conformal shape such that it can power, on-demand, sensor nodes located in non-line-of-sight (NLOS) and difficult-to-reach positions. This allows for eliminating the periodic battery replacement of the customized sensor nodes, which are designed to be compact, low-power, and robust. A measurement campaign has been conducted in a real scenario, i.e., the engine compartment of a car, assuming the exploitation of the system in the automotive field. Our work demonstrates that a one radio-frequency (RF) source (illuminator) with a maximum effective isotropic radiated power (EIRP) of 27 dBm is capable of transferring the energy of 4.8 mJ required to fully charge the sensor node in less than 170 s, in the worst case of 112-cm distance between illuminator and node (NLOS). We also show how, in the worst case, the transferred power allows the node to operate every 60 s, where operation includes sampling accelerometer data for 1 s, extracting statistical information, transmitting a 20-byte payload, and receiving a 3-byte acknowledgment using the extremely robust Long Range (LoRa) communication technology. The energy requirement for an active cycle is between 1.45 and 1.65 mJ, while sleep mode current consumption is less than 150 nA, allowing for achieving the targeted battery-free operation with duty cycles as high as 1.7%.<\/jats:p>","DOI":"10.3390\/s21020386","type":"journal-article","created":{"date-parts":[[2021,1,10]],"date-time":"2021-01-10T23:03:42Z","timestamp":1610319822000},"page":"386","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["RF-Powered Low-Energy Sensor Nodes for Predictive Maintenance in Electromagnetically Harsh Industrial Environments"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5001-2689","authenticated-orcid":false,"given":"Giacomo","family":"Paolini","sequence":"first","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9801-5769","authenticated-orcid":false,"given":"Marco","family":"Guermandi","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5340-2781","authenticated-orcid":false,"given":"Diego","family":"Masotti","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"},{"name":"ARCES\u2014Advanced Research Center on Electronic Systems \u201cErcole De Castro\u201d, University of Bologna, 40125 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0479-0930","authenticated-orcid":false,"given":"Mazen","family":"Shanawani","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"},{"name":"ARCES\u2014Advanced Research Center on Electronic Systems \u201cErcole De Castro\u201d, University of Bologna, 40125 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5870-0355","authenticated-orcid":false,"given":"Francesca","family":"Benassi","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luca","family":"Benini","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"},{"name":"D-ITET\u2014Department of Information Technology and Electrical Engineering, ETH Z\u00fcrich, 8092 Z\u00fcrich, Switzerland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alessandra","family":"Costanzo","sequence":"additional","affiliation":[{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 40136 Bologna, Italy"},{"name":"ARCES\u2014Advanced Research Center on Electronic Systems \u201cErcole De Castro\u201d, University of Bologna, 40125 Bologna, Italy"},{"name":"DEI\u2014Department of Electrical, Electronic and Information Engineering \u201cGuglielmo Marconi\u201d, University of Bologna, 47521 Cesena, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1900","DOI":"10.1109\/JSEN.2008.2006452","article-title":"New Automotive Sensors\u2014A Review","volume":"8","author":"Fleming","year":"2008","journal-title":"IEEE Sens. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"2092","DOI":"10.1109\/JIOT.2017.2754981","article-title":"Development of an Indoor Photovoltaic Energy Harvesting Module for Autonomous Sensors in Building Air Quality Applications","volume":"4","author":"Yue","year":"2017","journal-title":"IEEE Internet Things J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1871","DOI":"10.1109\/TIE.2013.2267694","article-title":"Extended Wireless Monitoring Through Intelligent Hybrid Energy Supply","volume":"61","author":"Magno","year":"2014","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Magno, M., Kneub\u00fchler, D., Mayer, P., and Benini, L. (2018, January 20\u201322). Micro Kinetic Energy Harvesting for Autonomous Wearable Devices. Proceedings of the 2018 International Symposium on Power Electronics, Electrical Drives, Automation and Motion, Amalfi, Italy.","DOI":"10.1109\/SPEEDAM.2018.8445342"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Magno, M., Sigrist, L., Gomez, A., Cavigelli, L., Libri, A., Popovici, E., and Benini, L. (2019). SmarTEG: An Autonomous Wireless Sensor Node for High Accuracy Accelerometer-Based Monitoring. Sensors, 19.","DOI":"10.3390\/s19122747"},{"key":"ref_6","first-page":"3530","article-title":"A Novel Thermoelectric Energy Harvester for Wireless Sensor Network Application","volume":"66","author":"Verma","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Ma, Y., Ji, Q., Chen, S., and Song, G. (2017). An experimental study of ultra-low power wireless sensor-based autonomous energy harvesting system. J. Renew. Sustain. Energy, 9.","DOI":"10.1063\/1.4997274"},{"key":"ref_8","unstructured":"Hayashi, H., and Ueda, T. (2012, January 20\u201323). Requirements and considerations of energy harvesting for industrial wireless transmitter. Proceedings of the SICE Annual Conference, Akita, Japan."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Viehweger, C., Keutel, T., and Kanoun, O. (2014, January 11\u201314). Energy harvesting for wireless sensor nodes in factory environments. Proceedings of the IEEE 11th International Multi-Conference on Systems, Signals & Devices, Barcelona, Spain.","DOI":"10.1109\/SSD.2014.6808913"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1649","DOI":"10.1109\/JPROC.2014.2357031","article-title":"Ambient RF Energy-Harvesting Technologies for Self-Sustainable Standalone Wireless Sensor Platforms","volume":"102","author":"Kim","year":"2014","journal-title":"Proc. IEEE"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Berger, A., H\u00f6rmann, L.B., Leitner, C., Oswald, S.B., Priller, P., and Springer, A. (2015, January 13\u201315). Sustainable energy harvesting for robust wireless sensor networks in industrial applications. Proceedings of the IEEE Sensors Applications Symposium, Zadar, Croatia.","DOI":"10.1109\/SAS.2015.7133585"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"509","DOI":"10.1109\/TIE.2018.2807414","article-title":"Early Fault Detection of Machine Tools Based on Deep Learning and Dynamic Identification","volume":"66","author":"Luo","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"6337","DOI":"10.1109\/TIE.2014.2311395","article-title":"A 1-kW Contactless Energy Transfer System Based on a Rotary Transformer for Sealing Rollers","volume":"61","author":"Trevisan","year":"2014","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"4130","DOI":"10.1109\/TIE.2018.2860529","article-title":"Modeling and Design of Contactless Sliprings for Rotary Applications","volume":"66","author":"He","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Gong, C.-S.A., Li, S.-W., and Shiue, M.-T. (2019). A Bootstrapped Comparator-Switched Active Rectifying Circuit for Wirelessly Powered Integrated Miniaturized Energy Sensing Systems. Sensors, 19.","DOI":"10.3390\/s19214714"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Popovic, Z. (2013, January 15\u201316). Far-field wireless power delivery and power management for low-power sensors. Proceedings of the IEEE Wireless Power Transfer, Perugia, Italy.","DOI":"10.1109\/WPT.2013.6556867"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Zannas, K., Matbouly, H.E., Duroc, Y., and Tedjini, S. (2019, January 2\u20137). Flipping a Coin, Heads or Tails. Flipping an RFID Tag on Metal, ETSI or FCC Bands. Proceedings of the IEEE MTT-S International Microwave Symposium, Boston, MA, USA.","DOI":"10.1109\/MWSYM.2019.8700808"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1109\/JSAC.2018.2872615","article-title":"Fundamentals of Wireless Information and Power Transfer: From RF Energy Harvester Models to Signal and System Designs","volume":"37","author":"Clerckx","year":"2019","journal-title":"IEEE J. Sel. Areas Commun."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"4013","DOI":"10.1109\/TIE.2018.2831196","article-title":"Simultaneous Wireless Power and Bidirectional Information Transmission With a Single-Coil, Dual-Resonant Structure","volume":"66","author":"Ji","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Br\u00e1s, L., Oliveira, M., de Carvalho, N.B., and Pinho, P. (2010, January 15\u201317). Low power location protocol based on ZigBee Wireless Sensor Networks. Proceedings of the 2010 International Conference on Indoor Positioning and Indoor Navigation, Zurich, Switzerland.","DOI":"10.1109\/IPIN.2010.5647869"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Paolini, G., Shanawani, M., Costanzo, A., Benassi, F., and Masotti, D. (2020, January 4\u20136). RF Energy On-Demand for Automotive Applications. Proceedings of the IEEE\/MTT-S International Microwave Symposium, Los Angeles, CA, USA.","DOI":"10.1109\/IMS30576.2020.9224078"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"949","DOI":"10.1109\/TAP.1983.1143162","article-title":"Analysis and optimized design of single feed circularly polarized microstrip antennas","volume":"31","author":"Sharma","year":"1983","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"4511","DOI":"10.1109\/TMTT.2015.2494003","article-title":"A 2.45-GHz Energy-Autonomous Wireless Power Relay Node","volume":"63","author":"Costanzo","year":"2015","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"994","DOI":"10.1109\/TMTT.2014.2304703","article-title":"A Load-Modulated Rectifier for RF Micropower Harvesting With Start-Up Strategies","volume":"62","author":"Masotti","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Tang, X., Wang, X., Cattley, R., Gu, F., and Ball, A.D. (2018). Energy Harvesting Technologies for Achieving Self-Powered Wireless Sensor Networks in Machine Condition Monitoring: A Review. Sensors, 18.","DOI":"10.3390\/s18124113"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1397","DOI":"10.1109\/JPROC.2013.2244053","article-title":"Low-Power Far-Field Wireless Powering for Wireless Sensors","volume":"101","author":"Popovic","year":"2013","journal-title":"Proc. IEEE"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Sung, G.-M., Chung, C.-K., Lai, Y.-J., and Syu, J.-Y. (2019). Small-Area Radiofrequency-Energy-Harvesting Integrated Circuits for Powering Wireless Sensor Networks. Sensors, 19.","DOI":"10.3390\/s19081754"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"La Rosa, R., Livreri, P., Trigona, C., Di Donato, L., and Sorbello, G. (2019). Strategies and techniques for powering wireless sensor nodes through energy harvesting and wireless power transfer. Sensors, 19.","DOI":"10.3390\/s19122660"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/2\/386\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:08:21Z","timestamp":1760159301000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/2\/386"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,1,8]]},"references-count":28,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2021,1]]}},"alternative-id":["s21020386"],"URL":"https:\/\/doi.org\/10.3390\/s21020386","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,1,8]]}}}