{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,14]],"date-time":"2025-10-14T00:43:28Z","timestamp":1760402608872,"version":"build-2065373602"},"reference-count":19,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,5,1]],"date-time":"2020-05-01T00:00:00Z","timestamp":1588291200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministerio de Econom\u00eda y Competitividad (MINECO), Spain","award":["TEC2016-78028-C3-2-P"],"award-info":[{"award-number":["TEC2016-78028-C3-2-P"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>This paper presents the design and features of frequency-selective wallpaper\u2014based on periodic and symmetric metallic hexagons\u2014intended to be attached to standard walls for filtering out 5 GHz signals (e.g., IEEE 802.11a systems) without blocking other selected radio communication services (e.g., cellular mobile communication signals). It analyzes the characteristics of the radio channel\u2014as found within standard indoor environments\u2014with both regular walls and walls with the proposed frequency-selective wallpaper, examined using a ray-launching program for single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems. This allows the harvesting of parameters, including channel capacity, power delay profile, and signal-to-interference ratio, for proper comparison between the two environments under study: with and without the presented wallpaper. The achieved results clearly show that the use of the proposed frequency-selective wallpaper in an indoor scenario reduces interference levels by an additional attenuation of up to 20 dB in comparison to an unpapered wall. Additionally, with MIMO systems, radio channel characteristics, such as capacity, are improved due to the increase in the magnitude of all singular values of the channel transfer matrix compared to the unpapered wall case, thereby leading to the existence of more relevant subchannels.<\/jats:p>","DOI":"10.3390\/sym12050695","type":"journal-article","created":{"date-parts":[[2020,5,5]],"date-time":"2020-05-05T06:41:20Z","timestamp":1588660880000},"page":"695","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Frequency-Selective Wallpaper for Indoor Interference Reduction and MIMO Capacity Improvement"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3298-6439","authenticated-orcid":false,"given":"Jos\u00e9-V\u00edctor","family":"Rodr\u00edguez","sequence":"first","affiliation":[{"name":"Departamento de Tecnolog\u00edas de la Informaci\u00f3n y las Comunicaciones, Universidad Polit\u00e9cnica de Cartagena, E30202 Cartagena, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mats","family":"Gustafsson","sequence":"additional","affiliation":[{"name":"Department of Electrical and Information Technology, Lund University, Box 118, SE-221 00 Lund, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6415-7363","authenticated-orcid":false,"given":"Jos\u00e9-Mar\u00eda","family":"Molina-Garc\u00eda-Pardo","sequence":"additional","affiliation":[{"name":"Departamento de Tecnolog\u00edas de la Informaci\u00f3n y las Comunicaciones, Universidad Polit\u00e9cnica de Cartagena, E30202 Cartagena, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1046-3466","authenticated-orcid":false,"given":"Leandro","family":"Juan-Ll\u00e1cer","sequence":"additional","affiliation":[{"name":"Departamento de Tecnolog\u00edas de la Informaci\u00f3n y las Comunicaciones, Universidad Polit\u00e9cnica de Cartagena, E30202 Cartagena, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0118-3406","authenticated-orcid":false,"given":"Ignacio","family":"Rodr\u00edguez-Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Departamento de Ingenier\u00eda de Comunicaciones, ATIC Research Group, Universidad de M\u00e1laga, E29071 M\u00e1laga, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,1]]},"reference":[{"doi-asserted-by":"crossref","unstructured":"Niembro-Martin, A., De Barros, F., Eymin-Petot-Tourtollet, G., Lemaitre-Auger, P., Pistono, E., and Vuong, T.-P. 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