{"id":27882,"date":"2025-10-02T10:31:47","date_gmt":"2025-10-02T08:31:47","guid":{"rendered":"https:\/\/wp.eurestools.eu\/key_achievement\/characterisation-of-indoor-ris-assisted-channels-at-304-ghz-path-gain-and-power-angular-profile-measurements\/"},"modified":"2025-10-02T10:31:47","modified_gmt":"2025-10-02T08:31:47","slug":"characterisation-of-indoor-ris-assisted-channels-at-304-ghz-path-gain-and-power-angular-profile-measurements","status":"publish","type":"key_achievement","link":"https:\/\/wp.eurestools.eu\/de\/key_achievement\/characterisation-of-indoor-ris-assisted-channels-at-304-ghz-path-gain-and-power-angular-profile-measurements\/","title":{"rendered":"Charakterisierung von RIS-gest\u00fctzten Indoor-Kan\u00e4len bei 304 GHz: Path Gain und Power Winkelprofilmessungen"},"content":{"rendered":"","protected":false},"featured_media":0,"template":"","class_list":["post-27882","key_achievement","type-key_achievement","status-publish","hentry"],"acf":{"logo":"https:\/\/smart-networks.europa.eu\/wp-content\/uploads\/2025\/08\/terrameta.png","diagram":"https:\/\/smart-networks.europa.eu\/wp-content\/uploads\/advanced-cf7-upload\/A32025053002.png","top10":"","project_name":"TERRAMETA","ka_number":"3","description":"TERRAMETA conducted the first measurement campaign at 304?GHz, incorporating Reconfigurable Intelligent Surfaces (RISs), aiming to develop realistic channel models at sub-THz frequencies. Three static RISs were designed and fabricated, each comprising 100a\u2014100 unit cells with half-wavelength spacing, that emulate 1-, 2-, and 3-bit phase quantisation through control of the geometrical patterns of the unit cell.\nTwo setups were implemented. The first measured end-to-end path gain in a Tx-RIS-Rx configuration. We showed that increasing phase quantisation enhances RIS gain, with the 3-bit RIS achieving the strongest link in Non Line of Sight (NLoS) indoor scenarios and outperforming natural reflections from walls and floors; this confirmed the role of RISs in coverage extension at sub-THz bands. The measurements spanned far-field to near-field distances, and it was demonstrated that the Rayleigh distance does not delimit RIS effectiveness, instead, RIS gain starts to deviate at around one-tenth of the Rayleigh distance due to near-field propagation effects, validating that the far-field approximation can be applied for RIS designs even in deep near-field conditions.\nThe second setup analysed the Power Angular Profile (PAP). It was showcased that across the RISs, higher phase resolution yielded greater spatial diversity: more refined beamforming contributed additional distinguishable multipath components due to the increased path gain.\nOverall, our results provide the first empirical dataset for understanding RIS-assisted propagation at sub-THz frequencies, quantifying the impact of phase quantisation, near-field effects, and angular characteristics of the cascaded channel.","references":"TERRAMETA Deliverable D5.1, \"Channel models, channel estimation and beam management with THz metasurface-based transceivers (interim),\" June 2024. \nG. C. Alexandropoulos, L. H. W. Loeser, P. Gavriilidis, S. Matos, B. K. Jung, V. Elesina, A. Clemente, R. D'Errico, L. M. Pessoa, and T. Ka\u00bcrner, \"Characterization of indoor RIS-assisted channels at 304 GHz: Experimental measurements, challenges, and future directions,\" IEEE Vehicular Technology Magazine, under revision, 2025. [Online: https:\/\/arxiv.org\/abs\/2412.07359] \nB. K. Jung, J. M. Eckhardt, V. V. Elesina, and T. Ka\u00bcrner, \"Double directional channel measurements at 300 GHz in indoor environments enhanced by reconfigurable intelligent surfaces,\"\u009d in Proc. Eur. Conf. Antennas Propag., Stockholm, Sweden, 2025.","category":"CAT-2: Experimentation (Infrastructure \/ Tool Creation, Performance Evaluation)","sub_categories":"","call":"Call 1"},"_links":{"self":[{"href":"https:\/\/wp.eurestools.eu\/de\/wp-json\/wp\/v2\/key_achievement\/27882","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.eurestools.eu\/de\/wp-json\/wp\/v2\/key_achievement"}],"about":[{"href":"https:\/\/wp.eurestools.eu\/de\/wp-json\/wp\/v2\/types\/key_achievement"}],"wp:attachment":[{"href":"https:\/\/wp.eurestools.eu\/de\/wp-json\/wp\/v2\/media?parent=27882"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}