{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:20:49Z","timestamp":1760059249690,"version":"build-2065373602"},"reference-count":19,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,5,31]],"date-time":"2025-05-31T00:00:00Z","timestamp":1748649600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>A method for characterizing carbon nanotubes (CNTs) in powder form with different packing densities in the microwave regions is proposed. The CNTs were sandwiched between two dielectric walls in (Polyvinyl Chloride) PVC and put in a waveguide shim. We measured the transmission\/reflection S-parameters of the waveguide using a Vector Network Analysis (VNA), and the impacts of the PVCs on the measured S-parameters were de-embedded by microwave network analysis. Then, the well-known Nicolson\u2013Ross\u2013Weir (NRW) method was processed to determine the complex permittivity and permeability of the CNTs. Furthermore, we pressed the PVC to increase the packing densities of the CNTs. The results of the characterization can be employed to design microwave devices using the CNTs.<\/jats:p>","DOI":"10.3390\/mi16060662","type":"journal-article","created":{"date-parts":[[2025,6,2]],"date-time":"2025-06-02T12:27:09Z","timestamp":1748867229000},"page":"662","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Characterizing Method of Carbon Nanotubes in Powder Form with Different Packing Densities"],"prefix":"10.3390","volume":"16","author":[{"given":"Ruiliang","family":"Li","sequence":"first","affiliation":[{"name":"Qingdao Institute for Marine Technology of Tianjin University, Qingdao 266200, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chuang","family":"Yang","sequence":"additional","affiliation":[{"name":"School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yunlong","family":"Zhang","sequence":"additional","affiliation":[{"name":"Qingdao ZITN Micro-Electronics Company Limited, Qingdao 266114, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4361-8946","authenticated-orcid":false,"given":"Jian","family":"Wang","sequence":"additional","affiliation":[{"name":"Qingdao Institute for Marine Technology of Tianjin University, Qingdao 266200, China"},{"name":"School of Microelectronics, Tianjin University, Tianjin 300072, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1038\/354056a0","article-title":"Helical microtubules of graphitic carbon","volume":"354","author":"Iijima","year":"1991","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"153108","DOI":"10.1063\/1.2193464","article-title":"Experimental determination of microwave attenuation and electrical permittivity of double-walled carbon nanotubes","volume":"88","author":"Dragoman","year":"2006","journal-title":"Appl. Phys. Lett."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"033503","DOI":"10.1063\/5.0232542","article-title":"Advanced optical reinforcement materials based on three-dimensional four-way weaving structure and metasurface technology","volume":"126","author":"Li","year":"2025","journal-title":"Appl. Phys. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"130262","DOI":"10.1016\/j.physleta.2025.130262","article-title":"Ultrathin broadband terahertz metamaterial based on single-layer nested patterned graphene","volume":"534","author":"Li","year":"2025","journal-title":"Phys. Lett. A"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1109\/TMTT.2007.914627","article-title":"Microwave (8\u201350 GHz) Characterization of Multiwalled Carbon Nanotube Papers Using Rectangular Waveguides","volume":"56","author":"Wang","year":"2008","journal-title":"IEEE Trans. Microwave Theory Tech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2719","DOI":"10.1109\/TMTT.2011.2160197","article-title":"Terahertz Characterization of Single-Walled Carbon Nanotube and Graphene On-Substrate Thin Films","volume":"59","author":"Liang","year":"2011","journal-title":"IEEE Trans. Microwave Theory Tech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"4134","DOI":"10.1063\/1.1400100","article-title":"Effect of purification of the electrical conductivity and complex permittivity of multiwall carbon nanotubes","volume":"90","author":"Grimes","year":"2001","journal-title":"J. Appl. Phys."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1109\/LMWC.2008.916776","article-title":"Characterization of Multiwalled Carbon Nanotube (MWCNT) Composites in a Waveguide of Square Cross Section","volume":"18","author":"Challa","year":"2008","journal-title":"Microwave Wireless Compon. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1109\/TEMC.2011.2174788","article-title":"Rigorous Characterization of Carbon Nanotube Complex Permittivity Over a Broadband of RF Frequencies","volume":"54","author":"Decrossas","year":"2012","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"52","DOI":"10.1109\/TEMC.2011.2179119","article-title":"Engineered Carbon-Nanotubes-Based Composite Material for RF Applications","volume":"54","author":"Decrossas","year":"2012","journal-title":"IEEE Trans. Electromagn. Compat."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Ji, Z., Song, Y., Gao, M., Zhang, Q., and Liu, Y. (2024). Multimode Miniature Polarization-Sensitive Metamaterial Absorber with Ultra-Wide Bandwidth in the K Band. Micromachines, 15.","DOI":"10.3390\/mi15121446"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"753","DOI":"10.1002\/mop.32702","article-title":"Determination of unique and stable complex permittivity of granular materials from transmission and reflection measurements","volume":"63","author":"Yang","year":"2020","journal-title":"Microwave Opt. Technol. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"419","DOI":"10.1109\/LMWC.2009.2020045","article-title":"Noniterative Permittivity Extraction of Lossy Liquid Materials From Reflection Asymmetric Amplitude-Only Microwave Measurements","volume":"19","author":"Hasar","year":"2009","journal-title":"Microwave Wireless Compon. Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1109\/TIM.2005.861249","article-title":"Electromagnetic Characterization of Layered Materials via Direct and De-embed Methods","volume":"55","author":"Havrilla","year":"2006","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Collin, R.E. (1991). Field Theory of Guided Waves, IEEE Press. [2nd ed.].","DOI":"10.1109\/9780470544648"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1109\/PROC.1974.9382","article-title":"Automatic Measurement of Complex Dielectric Constant and Permeability at Microwave Frequencies","volume":"62","author":"Weir","year":"1974","journal-title":"Proc. IEEE"},{"key":"ref_17","unstructured":"Pozar, D.M. (2011). Microwave Engineering, Wiley. [4th ed.]."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1971","DOI":"10.1109\/LAWP.2019.2935170","article-title":"A Noniterative and Efficient Technique to Extract Complex Permittivity of Low-Loss Dielectric Materials at Terahertz Frequencies","volume":"18","author":"Yang","year":"2019","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"693","DOI":"10.1109\/LMWC.2019.2933350","article-title":"Direct Extraction of Complex Permittivity and Permeability of Materials on a Known-Substrate From Transmission\/Reflection Measurements","volume":"29","author":"Yang","year":"2019","journal-title":"IEEE Microwave Wireless Compon. Lett."}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/16\/6\/662\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:44:33Z","timestamp":1760031873000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/16\/6\/662"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,5,31]]},"references-count":19,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2025,6]]}},"alternative-id":["mi16060662"],"URL":"https:\/\/doi.org\/10.3390\/mi16060662","relation":{},"ISSN":["2072-666X"],"issn-type":[{"type":"electronic","value":"2072-666X"}],"subject":[],"published":{"date-parts":[[2025,5,31]]}}}