{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T10:47:58Z","timestamp":1781174878981,"version":"3.54.1"},"reference-count":45,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,12,22]],"date-time":"2022-12-22T00:00:00Z","timestamp":1671667200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Framework Agreement between University of Pitesti (Romania) and King Mongkut\u2019s University of Technology North Bangkok (Thailand)","award":["N42A640328"],"award-info":[{"award-number":["N42A640328"]}]},{"name":"International Research Partnership \u201cElectrical Engineering\u2013Thai French Research Center (EE-TFRC)\u201d under the project framework of the Lorraine Universit\u00e9 d\u2019Excellence (LUE) in cooperation between Universit\u00e9 de Lorraine and King Mongkut\u2019s University of Technology North Bangkok","award":["N42A640328"],"award-info":[{"award-number":["N42A640328"]}]},{"DOI":"10.13039\/501100004704","name":"National Research Council of Thailand (NRCT) under Senior Research Scholar Program","doi-asserted-by":"publisher","award":["N42A640328"],"award-info":[{"award-number":["N42A640328"]}],"id":[{"id":"10.13039\/501100004704","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>Metamaterial absorbers are used in the terahertz frequency regime as photo-detectors, as sensing elements, in imaging applications, etc. Narrowband absorbers, on account of their ultra-slender bandwidth within the terahertz frequency spectrum, show a significant shift in the absorption peak when an extrinsic entity relative to the absorber, like refractive index or temperature of the encircling medium, is altered. This property paves the path for the narrowband absorbers to be used as potential sensors to detect any alterations in the encircling medium. In this paper, a novel design of a terahertz metamaterial (MTM) absorber is proposed, which can sense the variations in the refractive index (RI) of the surrounding medium. The effective permeability of the structure is negative, while its permittivity is positive; thus, it is a \u03bc-negative metamaterial. The layout involves a swastika-shaped design made of gold on top of a dielectric gallium arsenide (GaAs) substrate. The proposed absorber achieved a nearly perfect absorption of 99.65% at 2.905 terahertz (THz), resulting in a quality factor (Q-factor) of 145.25. The proposed design has a sensitivity of 2.12 THz\/RIU over a range of varied refractive index from n = 1.00 to n = 1.05 with a step size of 0.005, thereby achieving a Figure of Merit (FoM) of 106. Furthermore, the sensor was found to have a polarization-insensitive characteristic. Considering its high sensitivity (S), the proposed sensor was further tested for gas sensing applications of harmful gases. As a case study, the sensor was used to detect chloroform. The proposed work can be the foundation for developing highly sensitive gas sensors.<\/jats:p>","DOI":"10.3390\/sym15010024","type":"journal-article","created":{"date-parts":[[2022,12,22]],"date-time":"2022-12-22T03:24:30Z","timestamp":1671679470000},"page":"24","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":37,"title":["A New Design of a Terahertz Metamaterial Absorber for Gas Sensing Applications"],"prefix":"10.3390","volume":"15","author":[{"given":"Sagnik","family":"Banerjee","sequence":"first","affiliation":[{"name":"Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, Via Eudossiana 18, 00184 Roma, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Purba","family":"Dutta","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Snehashish","family":"Basu","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7768-1236","authenticated-orcid":false,"given":"Sunil Kumar","family":"Mishra","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0878-7405","authenticated-orcid":false,"given":"Bhargav","family":"Appasani","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarita","family":"Nanda","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2808-2867","authenticated-orcid":false,"given":"Yadgar I.","family":"Abdulkarim","sequence":"additional","affiliation":[{"name":"Medical Physics Department, College of Medicals & Applied Science, Charmo University, Chamchamal 46023, Iraq"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4563-9671","authenticated-orcid":false,"given":"Fahmi F.","family":"Muhammadsharif","sequence":"additional","affiliation":[{"name":"Department of Physics, Faculty of Science and Health, Koya University, Koya 44023, Iraq"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8220-8424","authenticated-orcid":false,"given":"Jian","family":"Dong","sequence":"additional","affiliation":[{"name":"School of Computer Science and Engineering, Central South University, Changsha 410075, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1056-5617","authenticated-orcid":false,"given":"Amitkumar V.","family":"Jha","sequence":"additional","affiliation":[{"name":"School of Electronics Engineering, Kalinga Institute of Industrial Technology, Bhubaneswar 751024, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9311-7598","authenticated-orcid":false,"given":"Nicu","family":"Bizon","sequence":"additional","affiliation":[{"name":"Faculty of Electronics, Communication and Computers, University of Pitesti, 110040 Pitesti, Romania"},{"name":"ICSI Energy, National Research and Development Institute for Cryogenic and Isotopic Technologies, 240050 Ramnicu Valcea, Romania"},{"name":"Doctoral School, Polytechnic University of Bucharest, 313 Splaiul Independentei, 060042 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1453-4236","authenticated-orcid":false,"given":"Phatiphat","family":"Thounthong","sequence":"additional","affiliation":[{"name":"Renewable Energy Research Centre (RERC), Department of Teacher Training in Electrical Engineering, Faculty of Technical Education, King Mongkut\u2019s University of Technology North Bangkok, 1518 Pracharat 1 Road, Wongsawang, Bangsue, Bangkok 10800, Thailand"},{"name":"Group of Research in Electrical Engineering of Nancy (GREEN), University of Lorraine-GREEN, F-54000 Nancy, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"157403","DOI":"10.1103\/PhysRevLett.97.157403","article-title":"Tunneling of electromagnetic energy through subwavelength channels and bends using epsilon-near-zero materials","volume":"97","author":"Silveirinha","year":"2006","journal-title":"Phys. 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