{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T11:05:38Z","timestamp":1778065538454,"version":"3.51.4"},"reference-count":124,"publisher":"MDPI AG","issue":"19","license":[{"start":{"date-parts":[[2024,9,30]],"date-time":"2024-09-30T00:00:00Z","timestamp":1727654400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Priorities Research Program (NPRP)","award":["NPRP13S-0122-200135"],"award-info":[{"award-number":["NPRP13S-0122-200135"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper briefly overviews and discusses the existing techniques using antennas for passive sensing, starting from the antenna operating principle and antenna structural design to different antenna-based sensing mechanisms. The effects of different electrical properties of the material used to design an antenna, such as conductivity, loss tangent, and resistivity, are discussed to illustrate the fundamental sensing mechanisms. Furthermore, the key parameters, such as operating frequency and antenna impedance, along with the factors affecting the sensing performance, are discussed. Overall, passive sensing using an antenna is mainly achieved by altering the reflected wave characteristics in terms of center frequency, return loss, phase, and received\/reflected signal strength. The advantages and drawbacks of each technique are also discussed briefly. Given the increasing relevance, millimeter-wave antenna sensors and resonator sensors are also discussed with their applications and recent advancements. This paper primarily focuses on microstrip-based radiating structures and insights for further sensing performance improvement using passive antennas, which are outlined in this study. In addition, suggestions are made for the current scientific and technical challenges, and future directions are discussed.<\/jats:p>","DOI":"10.3390\/s24196355","type":"journal-article","created":{"date-parts":[[2024,9,30]],"date-time":"2024-09-30T11:32:05Z","timestamp":1727695925000},"page":"6355","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":29,"title":["A Review of Microstrip Patch Antenna-Based Passive Sensors"],"prefix":"10.3390","volume":"24","author":[{"given":"Zain Ul","family":"Islam","sequence":"first","affiliation":[{"name":"College of Science and Engineering, Hamad Bin Khalifa University, Doha 34110, Qatar"}]},{"given":"Amine","family":"Bermak","sequence":"additional","affiliation":[{"name":"College of Science and Engineering, Hamad Bin Khalifa University, Doha 34110, Qatar"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9359-4869","authenticated-orcid":false,"given":"Bo","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Science and Engineering, Hamad Bin Khalifa University, Doha 34110, Qatar"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"McGrath, M.J., and Scanaill, C.N. (2013). Sensor Technologies: Healthcare, Wellness, and Environmental Applications, Springer Nature.","DOI":"10.1007\/978-1-4302-6014-1"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Huang, H. (2016). Antenna sensors in passive wireless sensing systems. Handb. Antenna Technol., 2795\u20132838.","DOI":"10.1007\/978-981-4560-44-3_86"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Tan, Q. (2020). Processing and manufacturing technology of special sensors. Precis. Mach., 401\u2013434.","DOI":"10.1007\/978-981-13-0381-4_23"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"177064","DOI":"10.1109\/ACCESS.2020.3027383","article-title":"Antenna design using modern additive manufacturing technology: A review","volume":"8","author":"Helena","year":"2020","journal-title":"IEEE Access"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"18022","DOI":"10.1109\/JSEN.2023.3292360","article-title":"Flexible Langasite-Based Surface Acoustic Wave Strain Sensor for High-Temperature Operation","volume":"23","author":"Li","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"8811","DOI":"10.1109\/TIE.2019.2891447","article-title":"A -12.3 dBm UHF passive RFID sense tag for grid thermal monitoring","volume":"66","author":"Wang","year":"2019","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"11867","DOI":"10.1109\/JSEN.2019.2936993","article-title":"Near-Field Microwave Loop Array Sensor for Breast Tumor Detection","volume":"19","author":"Aldhaeebi","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1109\/JERM.2020.3026588","article-title":"Implantable antennas for bio-medical applications","volume":"5","author":"Malik","year":"2020","journal-title":"IEEE J. Electromagn. RF Microwaves Med. Biol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"14035","DOI":"10.1109\/JSEN.2021.3068957","article-title":"An Implantable Antenna Sensor for Medical Applications","volume":"21","author":"Wang","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1109\/TBCAS.2022.3148725","article-title":"A Passive Smart Face Mask for Wireless Cough Monitoring: A Harmonic Detection Scheme With Clutter Rejection","volume":"16","author":"Zhu","year":"2022","journal-title":"IEEE Trans. Biomed. Circuits Syst."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Eldamak, A., and Fear, E. (2018). Conformal and Disposable Antenna-Based Sensor for Non-Invasive Sweat Monitoring. Sensors, 18.","DOI":"10.3390\/s18124088"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"22679","DOI":"10.1109\/JSEN.2021.3107462","article-title":"An Electromagnetic Band Gap-Based Complementary Split Ring Resonator Loaded Patch Antenna for Glucose Level Measurement","volume":"21","author":"Raj","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"544","DOI":"10.1109\/JSEN.2022.3223948","article-title":"Flexible Antenna Sensor in Thumb Spica Splint for Noninvasive Monitoring of Fluctuating Blood Glucose Levels","volume":"23","author":"Sindhuja","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TIM.2022.3214289","article-title":"Young\u2019s double slit method-based higher order mode surface plasmon microwave antenna sensor: Modeling, measurements, and application","volume":"71","author":"Kandwal","year":"2022","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"99058","DOI":"10.1109\/ACCESS.2023.3313939","article-title":"Microwave Biomedical Sensors with Stable Response: Basic Idea and Preliminary Numerical Assessments for Blood Glucose Monitoring","volume":"11","author":"Costanzo","year":"2023","journal-title":"IEEE Access"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"700","DOI":"10.1109\/OJAP.2022.3183750","article-title":"A compact slot-loaded antipodal vivaldi antenna for a microwave imaging system to monitor liver microwave thermal ablation","volume":"3","author":"Wang","year":"2022","journal-title":"IEEE Open J. Antennas Propag."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Lee, K., Hassan, A., Lee, C., and Bae, J. (2017). Microstrip Patch Sensor for Salinity Determination. Sensors, 17.","DOI":"10.3390\/s17122941"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"23751","DOI":"10.1109\/JSEN.2021.3112777","article-title":"Determination of Salinity and Sugar Concentration by Means of a Circular-Ring Monopole Textile Antenna-Based Sensor","volume":"21","author":"Gharbi","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"31","DOI":"10.2528\/PIERL22062901","article-title":"WB Antenna as a Sensor for the Analysis of Dissolved Particles and Water Quality","volume":"106","author":"Logeswaran","year":"2022","journal-title":"Prog. Electromagn. Res. Lett."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1385","DOI":"10.1109\/LMWT.2023.3286911","article-title":"Molecularly Imprinted Polymer Based Antenna Sensor for Methanol Vapor Sensing","volume":"33","author":"Hossain","year":"2023","journal-title":"IEEE Microw. Wirel. Technol. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"4846","DOI":"10.1109\/TMTT.2020.3006286","article-title":"Compact, Flexible Harmonic Transponder Sensor With Multiplexed Sensing Capabilities for Rapid, Contactless Microfluidic Diagnosis","volume":"68","author":"Zhu","year":"2020","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"6571","DOI":"10.1109\/JSEN.2019.2913143","article-title":"A molecularly imprinted polymer-graphene sensor antenna hybrid for ultra sensitive chemical detection","volume":"19","author":"Adams","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"12495","DOI":"10.1109\/JSEN.2020.3000778","article-title":"A Compact, Passive Frequency-Hopping Harmonic Sensor Based on a Microfluidic Reconfigurable Dual-Band Antenna","volume":"20","author":"Zhu","year":"2020","journal-title":"IEEE Sens. J."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1109\/JRFID.2020.3004351","article-title":"A Zero-Power Ubiquitous Wireless Liquid-Level Sensor Based on Microfluidic-Integrated Microstrip Antenna","volume":"4","author":"Zhu","year":"2020","journal-title":"IEEE J. Radio Freq. Identif."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"120176","DOI":"10.1109\/ACCESS.2021.3108906","article-title":"A Comprehensive Review of Portable Microwave Sensors for Grains and Mineral Materials Moisture Content Monitoring","volume":"9","author":"Javanbakht","year":"2021","journal-title":"IEEE Access"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/LSENS.2021.3115397","article-title":"Portable Microwave Sensor Based on Frequency-Selective Surface for Grain Moisture Content Monitoring","volume":"5","author":"Javanbakht","year":"2021","journal-title":"IEEE Sens. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/LSENS.2017.2779497","article-title":"RSSI evaluation model for quantitative power-oriented sensing using an omnidirectional antenna sensor","volume":"2","author":"Zeng","year":"2017","journal-title":"IEEE Sens. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Islam, M., Ashraf, F., Alam, T., Misran, N., and Mat, K. (2018). A Compact Ultrawideband Antenna Based on Hexagonal Split-Ring Resonator for pH Sensor Application. Sensors, 18.","DOI":"10.3390\/s18092959"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"13900","DOI":"10.1109\/JSEN.2023.3276426","article-title":"High Sensitivity SIW-CSRR Temperature Sensor Based on Microwave Scattering","volume":"23","author":"Zhang","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"5312","DOI":"10.1109\/JSEN.2015.2437884","article-title":"Microstrip patch antenna temperature sensor","volume":"15","author":"Sanders","year":"2015","journal-title":"IEEE Sens. J."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Yan, D., Yang, Y., Hong, Y., Liang, T., Yao, Z., Chen, X., and Xiong, J. (2018). Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor. Sensors, 18.","DOI":"10.3390\/s18020532"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"18733","DOI":"10.1109\/JSEN.2021.3089320","article-title":"Microwave Sensor for Detection of Ice Accretion on Base Station Antenna Radome","volume":"21","author":"Tariq","year":"2021","journal-title":"IEEE Sens. J."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Chung, K.L., Li, W., Xie, S., Song, C., and Zhang, C. (2019, January 19\u201322). A Loop Sensing Antenna for Corrosion Detection of FRP-Strengthened Steel Structure. Proceedings of the IEEE International Conference on Microwave and Millimeter Wave Technology (ICMMT), Guangzhou, China.","DOI":"10.1109\/ICMMT45702.2019.8992488"},{"key":"ref_34","first-page":"1","article-title":"Detection of Setting Time During Cement Hydration Using Multielectromagnetic Parameters of Patch Antenna Sensor","volume":"72","author":"Yi","year":"2023","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"027001","DOI":"10.1088\/0964-1726\/21\/2\/027001","article-title":"Passive wireless structural health monitoring sensor made with a flexible planar dipole antenna","volume":"21","author":"Jang","year":"2012","journal-title":"Smart Mater. Struct."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Kumar, L.A., and Maheswari, Y.U. (2023). Electromagnetic Interference and Electromagnetic Compatibility: Principles, Design, Simulation, and Applications, CRC Press.","DOI":"10.1201\/9781003362951"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Zhang, Y., and Rasmussen, K. (2020, January 18\u201321). Detection of Electromagnetic Interference Attacks on Sensor Systems. Proceedings of the 2020 IEEE Symposium on Security and Privacy (SP), Francisco, CA, USA.","DOI":"10.1109\/SP40000.2020.00001"},{"key":"ref_38","unstructured":"Skolnik, M.I. (2001). Introduction to Radar Systems, McGraw-Hill."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Cassidy, N.J., and Jol, H. (2009). Ground penetrating radar data processing, modelling and analysis. Ground Penetrating Radar Theory Appl., 141\u2013176.","DOI":"10.1016\/B978-0-444-53348-7.00005-3"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1167","DOI":"10.1049\/el:19950801","article-title":"Circular patch antenna sensor for moisture content measurement on dielectric material","volume":"31","author":"Gagnadre","year":"1995","journal-title":"Electron. Lett."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Siden, J., Zeng, X., Unander, T., Koptyug, A., and Nilsson, H.E. (2007, January 28\u201331). Remote Moisture Sensing utilizing Ordinary RFID Tags. Proceedings of the 2017 IEEE Sensors, Atlanta, GA, USA.","DOI":"10.1109\/ICSENS.2007.4388398"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Bhattacharyya, R., Floerkemeier, C., and Sarma, S. (2009, January 27\u201328). Towards tag antenna based sensing-An RFID displacement sensor. Proceedings of the 2009 IEEE International Conference on RFID, Orlando, FL, USA.","DOI":"10.1109\/RFID.2009.4911195"},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Bhattacharyya, R., Floerkemeier, C., Sarma, S., and Deavours, D. (2011, January 15\u201316). RFID tag antenna based temperature sensing in the frequency domain. Proceedings of the 2011 IEEE International Conference on RFID, Sitges, Spain.","DOI":"10.1109\/RFID.2011.5764639"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1109\/LAWP.2012.2199956","article-title":"A compact polyimide-based UWB antenna for flexible electronics","volume":"11","author":"Khaleel","year":"2012","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_45","unstructured":"Balanis, C.A. (2016). Antenna Theory: Analysis and Design, John Wiley & Sons. [4th ed.]."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"e23172","DOI":"10.1002\/mmce.23172","article-title":"Conformal metal crack detection sensor based on flexible graphene film antenna","volume":"32","author":"Tong","year":"2022","journal-title":"Int. J. RF Microw. Comput.-Aided Eng."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Sayem, S.M., and Esselle, K.P. (2021, January 19\u201322). A Robust, Flexible and Frequency Reconfigurable Antenna with Flexible Superstrate and Substrate. Proceedings of the International Symposium on Antennas and Propagation (ISAP), Taipei, Taiwan.","DOI":"10.23919\/ISAP47258.2021.9614601"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"27242","DOI":"10.1109\/JSEN.2023.3315695","article-title":"Design and Testing of Miniaturized Dual-Band Microstrip Antenna Sensor for Wireless Monitoring of High Temperatures","volume":"23","author":"Dong","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Al-Alem, Y., Sifat, S.M., Antar, Y.M., and Kishk, A.A. (2023). Millimeter-wave planar antenna array augmented with a low-cost 3D printed dielectric polarizer for sensing and internet of things (IoT) applications. Sci. Rep., 13.","DOI":"10.1038\/s41598-023-35707-2"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"3454","DOI":"10.1109\/JSEN.2018.2810132","article-title":"Effects of Soil Characteristics on Passive Wireless Sensor Interrogation","volume":"18","author":"Frolik","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1038\/s41746-020-0270-2","article-title":"Sweat monitoring beneath garments using passive, wireless resonant sensors interfaced with laser-ablated microfluidics","volume":"3","author":"Carr","year":"2020","journal-title":"NPJ Digit. Med."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Halmshaw, R., and Halmshaw, R. (1995). Basic properties of ionizing radiations. Ind. Radiol. Theory Pract., 9\u201332.","DOI":"10.1007\/978-94-011-0551-4_3"},{"key":"ref_53","unstructured":"Balanis, C.A. (2012). Advanced Engineering Electromagnetics, Wiley. [2nd ed.]."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"111837","DOI":"10.1016\/j.optmat.2021.111837","article-title":"Terahertz spectroscopic study of optical and dielectric properties of typical electrical insulation materials","volume":"123","author":"Nsengiyumva","year":"2022","journal-title":"Opt. Mater."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Lee, D.K., Kang, J.H., Lee, J.S., Kim, H.S., Kim, C., Hun Kim, J., Lee, T., Son, J.H., Park, Q.H., and Seo, M. (2015). Highly sensitive and selective sugar detection by terahertz nano-antennas. Sci. Rep., 5.","DOI":"10.1038\/srep15459"},{"key":"ref_56","unstructured":"Born, M., and Wolf, E. (2013). Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, Elsevier."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"2065","DOI":"10.1023\/A:1006792706134","article-title":"Modelling of drop size distribution of rain from rain rate and attenuation measurements at millimeter and optical wavelengths","volume":"21","author":"Bhattacharyya","year":"2000","journal-title":"Int. J. Infrared Millim. Waves"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"10027","DOI":"10.1109\/JSEN.2019.2921148","article-title":"Highly Sensitive Air-Filled Substrate Integrated Waveguide Resonator Integrated Wireless Passive Slot-Antenna for Confined Environmental Detection","volume":"19","author":"Kou","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_59","first-page":"e01816","article-title":"A review of dust-induced electromagnetic waves scattering theories and models for 5G and beyond wireless communication systems","volume":"21","author":"Alozie","year":"2023","journal-title":"Sci. Afr."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1109\/MAP.2009.5162049","article-title":"Definition and Misuse of Return Loss [Report of the Transactions Editor-in-Chief]","volume":"51","author":"Bird","year":"2009","journal-title":"IEEE Antennas Propag. Mag."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1109\/LMWC.2012.2212240","article-title":"Improved Expressions for Calculating the Impedance of Differential Feed Rectangular Microstrip Patch Antennas","volume":"22","author":"Tong","year":"2012","journal-title":"IEEE Microw. Wirel. Components Lett."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"24706","DOI":"10.1109\/ACCESS.2018.2830653","article-title":"A Review of Mutual Coupling in MIMO Systems","volume":"6","author":"Chen","year":"2018","journal-title":"IEEE Access"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"3105","DOI":"10.1109\/TAP.2007.908575","article-title":"Proximity Effects of Metallic Environments on High Frequency RFID Reader Antenna: Study and Applications","volume":"55","author":"Qing","year":"2007","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_64","unstructured":"DeJean, G.R., and Mercer, S. (2009). Antenna environment impacts efficiency and radiation pattern. High Freq. Electron., 18\u201327. Available online: https:\/\/www.highfrequencyelectronics.com\/Aug09\/HFE0809_Mercer.pdf."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"7192491","DOI":"10.1155\/2017\/7192491","article-title":"Statistical antenna proximity effect modeling with uncertainty impedance ellipses","volume":"2017","author":"Carro","year":"2017","journal-title":"Int. J. Antennas Propag."},{"key":"ref_66","unstructured":"Pozar, D.M. (2011). Microwave Engineering, John Wiley & Sons."},{"key":"ref_67","unstructured":"(2024, May 23). Basics of Measuring the Dielectric Properties of Materials: Application Note. Available online: https:\/\/www.keysight.com\/zz\/en\/assets\/7018-01284\/application-notes\/5989-2589.pdf."},{"key":"ref_68","unstructured":"(2024, May 23). Material Comparison. Available online: https:\/\/www.optiprint.ch\/de\/."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"919","DOI":"10.1109\/TAP.2009.2014574","article-title":"A textile antenna for off-body communication integrated into protective clothing for firefighters","volume":"57","author":"Hertleer","year":"2009","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_70","doi-asserted-by":"crossref","unstructured":"Ullah, M.A., Islam, M.T., Alam, T., and Ashraf, F.B. (2018). Paper-Based Flexible Antenna for Wearable Telemedicine Applications at 2.4 GHz ISM Band. Sensors, 18.","DOI":"10.3390\/s18124214"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1109\/LAWP.2018.2881303","article-title":"Millimeter-wave liquid crystal polymer based conformal antenna array for 5G applications","volume":"18","author":"Jilani","year":"2018","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"103","DOI":"10.2528\/PIERB22030704","article-title":"High temperature antennas: A review","volume":"95","author":"Younes","year":"2022","journal-title":"Prog. Electromagn. Res. B"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"104463","DOI":"10.1109\/ACCESS.2023.3316149","article-title":"Advances in Antenna-Based Techniques for Detection and Monitoring of Critical Chronic Diseases: A Comprehensive Review","volume":"11","author":"Chishti","year":"2023","journal-title":"IEEE Access"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"8314","DOI":"10.1109\/JSEN.2017.2765893","article-title":"A stacked dual-frequency microstrip patch antenna for simultaneous shear and pressure displacement sensing","volume":"17","author":"Huang","year":"2017","journal-title":"IEEE Sens. J."},{"key":"ref_75","unstructured":"(2024, May 23). Scattering Parameters. Available online: https:\/\/www.antenna-theory.com\/definitions\/sparameters.php."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TIM.2021.3065432","article-title":"Nondestructive Phase Variation-Based Chipless Sensing Methodology for Metal Crack Monitoring","volume":"70","author":"Norouzi","year":"2021","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"7796","DOI":"10.1109\/JSEN.2024.3357542","article-title":"A Phase Shift-Based and Quadrant-Distinguishable Passive Microstrip Antenna Sensor for Metal Crack Detection","volume":"24","author":"Tang","year":"2024","journal-title":"IEEE Sens. J."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"6121907","DOI":"10.1155\/2020\/6121907","article-title":"Design of a Novel Passive Wireless Integrated SAW-Based Antenna Sensor for Structural Health Monitoring","volume":"2020","author":"Dai","year":"2020","journal-title":"J. Sens."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"8004010","DOI":"10.1109\/TIM.2021.3132994","article-title":"A Phase Variation-Based Smart Structure for Crack Detection on Metals Using Cold Spray Additive Manufacturing","volume":"72","author":"Norouzi","year":"2023","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_80","doi-asserted-by":"crossref","unstructured":"Ali Khan, M.U., Raad, R., Tubbal, F., Theoharis, P.I., Liu, S., and Foroughi, J. (2021). Bending analysis of polymer-based flexible antennas for wearable, general IoT applications: A review. Polymers, 13.","DOI":"10.3390\/polym13030357"},{"key":"ref_81","doi-asserted-by":"crossref","unstructured":"Khan, M.U.A., Raad, R., Tubbal, F., and Ioannis Theoharis, P. (2021). The impact of bending on radiation characteristics of polymer-based flexible antennas for general IoT applications. Appl. Sci., 11.","DOI":"10.3390\/app11199044"},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"406","DOI":"10.13164\/re.2017.0406","article-title":"Non-invasive microwave sensors for biomedical applications: New design perspectives","volume":"26","author":"Costanzo","year":"2017","journal-title":"Radioengineering"},{"key":"ref_83","unstructured":"Rappaport, T.S. (1996). Wireless Communications: Principles and Practice, Prentice Hall PTR. [2nd ed.]."},{"key":"ref_84","doi-asserted-by":"crossref","unstructured":"Ye, Z., Ren, Y., Yang, M., Cheng, M.M.C., and Chen, P.Y. (November, January 29). Food Quality Monitoring Using A Low-Profile Multiplexed Harmonic Sensor. Proceedings of the 2023 IEEE Sensors, Vienna, Austria.","DOI":"10.1109\/SENSORS56945.2023.10324978"},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"3526","DOI":"10.1109\/TCSI.2022.3181543","article-title":"A \u00b10.5 dB, 6 nW RSSI circuit with RF power-to-digital conversion technique for ultra-low power IoT radio applications","volume":"69","author":"Mittal","year":"2022","journal-title":"IEEE Trans. Circuits Syst. I Regul. Pap."},{"key":"ref_86","unstructured":"(2024, May 23). RSSI Feature of the Si443x ISM Transceiver. Available online: https:\/\/community.silabs.com\/s\/article\/rssi-feature-of-the-si443x-ism-transceiver?language=en_US."},{"key":"ref_87","doi-asserted-by":"crossref","unstructured":"Iqbal, A., Smida, A., Saraereh, O.A., Alsafasfeh, Q.H., Mallat, N.K., and Lee, B.M. (2019). Cylindrical dielectric resonator antenna-based sensors for liquid chemical detection. Sensors, 19.","DOI":"10.3390\/s19051200"},{"key":"ref_88","doi-asserted-by":"crossref","unstructured":"Hasan, M.N., Tamanna, S., Singh, P., Nadeem, M.D., and Rudramuni, M. (2019, January 7\u20138). Cylindrical dielectric resonator antenna sensor for non-invasive glucose sensing application. Proceedings of the 2019 6th International Conference on Signal Processing and Integrated Networks (SPIN), Noida, India.","DOI":"10.1109\/SPIN.2019.8711633"},{"key":"ref_89","first-page":"101603","article-title":"High gain circularly polarized graphene inspired dielectric resonator antenna for 6G IOT THz optical communication and optical refractive index Biosensing applications","volume":"49","author":"Srivastava","year":"2024","journal-title":"Eng. Sci. Technol. Int. J."},{"key":"ref_90","doi-asserted-by":"crossref","unstructured":"Sheen, D.M., McMakin, D.L., and Hall, T.E. (2007). Detection of explosives by millimeter-wave imaging. Counterterrorist Detection Techniques of Explosives, Elsevier.","DOI":"10.1016\/B978-044452204-7\/50028-6"},{"key":"ref_91","doi-asserted-by":"crossref","first-page":"845","DOI":"10.1109\/TMTT.2011.2178427","article-title":"Millimeter-wave technology for automotive radar sensors in the 77 GHz frequency band","volume":"60","author":"Hasch","year":"2012","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_92","doi-asserted-by":"crossref","first-page":"771","DOI":"10.1109\/LAWP.2009.2026917","article-title":"Novel antenna concept for compact millimeter-wave automotive radar sensors","volume":"8","author":"Beer","year":"2009","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_93","doi-asserted-by":"crossref","first-page":"2372","DOI":"10.1109\/JPROC.2012.2184729","article-title":"Antenna concepts for millimeter-wave automotive radar sensors","volume":"100","author":"Menzel","year":"2012","journal-title":"Proc. IEEE"},{"key":"ref_94","doi-asserted-by":"crossref","first-page":"1707","DOI":"10.1109\/TMTT.2017.2677910","article-title":"Miniaturized millimeter-wave radar sensor for high-accuracy applications","volume":"65","author":"Pauli","year":"2017","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_95","doi-asserted-by":"crossref","unstructured":"Sato, H., Sawaya, K., Mizuno, K., Uemura, J., Takeda, M., Takahashi, J., Yamada, K., Morichika, K., Hasegawa, T., and Hirai, H. (2010, January 5\u20139). Passive millimeter-wave imaging for security and safety applications. Proceedings of the Terahertz Physics, Devices, and Systems IV: Advanced Applications in Industry and Defense, Orlando, FL, USA,.","DOI":"10.1117\/12.849491"},{"key":"ref_96","unstructured":"Nanzer, J.A. (2012). Microwave and Millimeter-Wave Remote Sensing for Security Applications, Artech House."},{"key":"ref_97","doi-asserted-by":"crossref","unstructured":"Du Preez, J., and Sinha, S. (2016). Millimeter-Wave Antennas: Configurations and Applications, Springer.","DOI":"10.1007\/978-3-319-35068-4"},{"key":"ref_98","doi-asserted-by":"crossref","unstructured":"Chittimoju, G., and Yalavarthi, U.D. (2021, January 25\u201326). A comprehensive review on millimeter waves applications and antennas. Proceedings of the Journal of Physics: Conference Series, Coimbatore, India.","DOI":"10.1088\/1742-6596\/1804\/1\/012205"},{"key":"ref_99","doi-asserted-by":"crossref","unstructured":"Chung, M.A., Lin, C.W., and Lo, W.J. (2022). Near Field Sensing Applications with Tunable Beam Millimeter Wave Antenna Sensors in an All-in-One Chip Design. Electronics, 11.","DOI":"10.3390\/electronics11142231"},{"key":"ref_100","doi-asserted-by":"crossref","unstructured":"Papotto, G., Parisi, A., Finocchiaro, A., Nocera, C., Cavarra, A., Castorina, A., and Palmisano, G. (2024). CMOS IC Solutions for the 77 GHz Radar Sensor in Automotive Applications. Electronics, 13.","DOI":"10.3390\/electronics13112104"},{"key":"ref_101","doi-asserted-by":"crossref","unstructured":"Soumya, A., Krishna Mohan, C., and Cenkeramaddi, L.R. (2023). Recent Advances in mmWave-Radar-Based Sensing, Its Applications, and Machine Learning Techniques: A Review. Sensors, 23.","DOI":"10.3390\/s23218901"},{"key":"ref_102","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.1109\/JSEN.2013.2295312","article-title":"High-sensitivity metamaterial-inspired sensor for microfluidic dielectric characterization","volume":"14","author":"Ebrahimi","year":"2013","journal-title":"IEEE Sens. J."},{"key":"ref_103","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1007\/s11664-019-07761-y","article-title":"Dual-band microwave sensor for investigation of liquid impurity concentration using a metamaterial complementary split-ring resonator","volume":"49","author":"Khanna","year":"2020","journal-title":"J. Electron. Mater."},{"key":"ref_104","doi-asserted-by":"crossref","first-page":"1100","DOI":"10.1109\/LAWP.2014.2329309","article-title":"Multiband high-gain printed Yagi array using square spiral ring metamaterial structures for S-band applications","volume":"13","author":"Khan","year":"2014","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_105","doi-asserted-by":"crossref","unstructured":"Jilani, M.T., Wen, W.P., Cheong, L.Y., and Ur Rehman, M.Z. (2016). A microwave ring-resonator sensor for non-invasive assessment of meat aging. Sensors, 16.","DOI":"10.3390\/s16010052"},{"key":"ref_106","doi-asserted-by":"crossref","first-page":"13134","DOI":"10.3390\/s140713134","article-title":"An aligned-gap and centered-gap rectangular multiple split ring resonator for dielectric sensing applications","volume":"14","author":"Rusni","year":"2014","journal-title":"Sensors"},{"key":"ref_107","doi-asserted-by":"crossref","first-page":"2010","DOI":"10.1109\/TMTT.2015.2418768","article-title":"Single-compound complementary split-ring resonator for simultaneously measuring the permittivity and thickness of dual-layer dielectric materials","volume":"63","author":"Lee","year":"2015","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_108","doi-asserted-by":"crossref","first-page":"107805","DOI":"10.1016\/j.measurement.2020.107805","article-title":"Dual-sensing and dual-frequency microwave SRR sensor for liquid samples permittivity detection","volume":"160","author":"Kiani","year":"2020","journal-title":"Measurement"},{"key":"ref_109","doi-asserted-by":"crossref","unstructured":"Mohd Bahar, A.A., Zakaria, Z., Md. Arshad, M., Isa, A., Dasril, Y., and Alahnomi, R.A. (2019). Real time microwave biochemical sensor based on circular SIW approach for aqueous dielectric detection. Sci. Rep., 9.","DOI":"10.1038\/s41598-019-41702-3"},{"key":"ref_110","doi-asserted-by":"crossref","first-page":"11880","DOI":"10.1109\/JSEN.2019.2938184","article-title":"Open complementary split-ring resonator sensor for dropping-based liquid dielectric characterization","volume":"19","author":"Lee","year":"2019","journal-title":"IEEE Sens. J."},{"key":"ref_111","doi-asserted-by":"crossref","first-page":"689","DOI":"10.1109\/TMTT.2014.2299514","article-title":"Improved split-ring resonator for microfluidic sensing","volume":"62","author":"Rowe","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_112","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.sna.2012.10.027","article-title":"Metamaterial-based microfluidic sensor for dielectric characterization","volume":"189","author":"Withayachumnankul","year":"2013","journal-title":"Sens. Actuators A Phys."},{"key":"ref_113","doi-asserted-by":"crossref","first-page":"1175","DOI":"10.1109\/TMTT.2019.2953580","article-title":"3-D printed microfluidic sensor in SIW technology for liquids\u2019 characterization","volume":"68","author":"Rocco","year":"2019","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_114","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1109\/TMTT.2014.2300066","article-title":"Novel microwave microfluidic sensor using a microstrip split-ring resonator","volume":"62","author":"Abduljabar","year":"2014","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_115","doi-asserted-by":"crossref","first-page":"693","DOI":"10.2528\/PIER13060904","article-title":"Novel miniaturized Koch pentagonal fractal antenna for multiband wireless applications","volume":"141","author":"Khan","year":"2013","journal-title":"Prog. Electromagn. Res."},{"key":"ref_116","doi-asserted-by":"crossref","unstructured":"Islam, Z.U., Rahman, M., Muhammad, N., Ahmed, Z., Lodhi, F.K., and Haneef, M. (2016, January 18\u201319). Dual band second order modified Sierpinski monopole reduced size fractal antenna. Proceedings of the 2016 International Conference on Emerging Technologies (ICET), Islamabad, Pakistan.","DOI":"10.1109\/ICET.2016.7813244"},{"key":"ref_117","doi-asserted-by":"crossref","first-page":"917","DOI":"10.1039\/D2MA00863G","article-title":"A highly sensitive and miniaturized wearable antenna based on MXene films for strain sensing","volume":"4","author":"Yin","year":"2023","journal-title":"Mater. Adv."},{"key":"ref_118","doi-asserted-by":"crossref","first-page":"100367","DOI":"10.1016\/j.flatc.2022.100367","article-title":"An MXene based flexible patch antenna for pressure and level sensing applications","volume":"33","author":"Sindhu","year":"2022","journal-title":"FlatChem"},{"key":"ref_119","doi-asserted-by":"crossref","first-page":"1060","DOI":"10.1109\/JSTSP.2021.3098478","article-title":"Wireless power transfer for future networks: Signal processing, machine learning, computing, and sensing","volume":"15","author":"Clerckx","year":"2021","journal-title":"IEEE J. Sel. Top. Signal Process."},{"key":"ref_120","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1109\/MNET.001.2100247","article-title":"Machine-learning-assisted signal detection in ambient backscatter communication networks","volume":"35","author":"Toro","year":"2021","journal-title":"IEEE Netw."},{"key":"ref_121","doi-asserted-by":"crossref","unstructured":"Mahinnezhad, S., Emami, H., Ketabi, M., Al Shboul, A., Belkhamssa, N., Shih, A., and Izquierdo, R. (November, January 31). Fully printed pH sensor based in carbon black\/polyaniline nanocomposite. Proceedings of the 2021 IEEE Sensors, Sydney, Australia.","DOI":"10.1109\/SENSORS47087.2021.9639597"},{"key":"ref_122","doi-asserted-by":"crossref","unstructured":"Cheng, T., Liu, C., and Ding, W. (2019, January 10\u201312). Weak signal detection based on deep learning. Proceedings of the 2019 4th International conference on Multimedia Systems and Signal Processing, Guangzhou, China.","DOI":"10.1145\/3330393.3330409"},{"key":"ref_123","doi-asserted-by":"crossref","first-page":"105009","DOI":"10.1088\/1361-665X\/ab2213","article-title":"Microstrip patch antenna for simultaneous temperature sensing and superstrate characterization","volume":"28","author":"Tchafa","year":"2019","journal-title":"Smart Mater. Struct."},{"key":"ref_124","doi-asserted-by":"crossref","unstructured":"Wang, S., Mei, L., Liu, R., Jiang, W., Yin, Z., Deng, X., and He, T. (2024). Multi-Modal Fusion Sensing: A Comprehensive Review of Millimeter-Wave Radar and Its Integration With Other Modalities. IEEE Commun. Surv. Tutor.","DOI":"10.1109\/COMST.2024.3398004"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/19\/6355\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:08:00Z","timestamp":1760112480000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/19\/6355"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,9,30]]},"references-count":124,"journal-issue":{"issue":"19","published-online":{"date-parts":[[2024,10]]}},"alternative-id":["s24196355"],"URL":"https:\/\/doi.org\/10.3390\/s24196355","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,9,30]]}}}